An antioxidant rare earth alloy modifier and a preparation method thereof

Abstract

This invention discloses an antioxidant rare earth alloy modifier and its preparation method. The rare earth alloy modifier has a fine-grained surface and columnar crystals inside. The thickness of the fine-grained surface region is 0.1~2mm, and the grain size is 100nm~1000μm. The width of the columnar crystals inside is ≥1mm, and the area of ​​the columnar crystal region accounts for 90%~99.5%. The proportion of longitudinal grain boundaries inside the rare earth alloy modifier is ≥95%, and the orientation deviation of the longitudinal grain boundaries is ≤25°, of which the proportion of small-angle grain boundaries below 15° is 10%~90%. By constructing a composite crystal structure of fine-grained surface and columnar crystals inside, oxygen permeation is hindered and the oxygen diffusion barrier is increased, significantly improving the intrinsic antioxidant performance of the rare earth alloy modifier. This solves the technical problems of existing technologies, such as the lack of durability of physical isolation protection, high cost of composition optimization, and difficulty in fundamentally inhibiting oxygen permeation.

Description

Technical Field

[0001] This invention relates to the field of rare earth alloy materials, and in particular to an antioxidant rare earth alloy modifier and its preparation method. Background Technology

[0002] Rare earth elements, due to their unique electronic structure, are hailed as "vitamins of modern industry" and play a vital role in the field of materials science. Adding rare earth elements to metallic materials can induce significant lattice distortion, resulting in a strong solid solution strengthening effect. Simultaneously, rare earth elements have high chemical reactivity, preferentially reacting with harmful impurities such as oxygen and sulfur in the melt, thus playing a role in melt deoxidation, purification, and inclusion modification. Furthermore, rare earth elements can also serve as microalloying elements to refine the solidification structure of materials, thereby comprehensively improving the mechanical and performance properties of the materials.

[0003] However, due to their high chemical activity and poor oxidation resistance, rare earth master alloys are prone to surface oxidation and even pulverization during storage, transportation, and practical applications. This problem reduces the content of effective rare earth elements and the utilization rate of rare earths in the master alloys, leading to resource waste. Furthermore, oxidation products (rare earth oxides) are introduced into the material preparation process, affecting not only the smoothness and stability of the preparation process but also potentially reducing the uniformity and yield of the final product, thus failing to fully realize the superior effects of rare earth elements. Therefore, effectively improving the oxidation resistance of rare earth master alloys and maximizing the role of rare earth elements has become a pressing problem to be solved in this field.

[0004] Currently, the main technical means to improve the oxidation resistance of rare earth master alloys is through physical isolation, such as coating the alloy surface with an organic film, applying an anti-aging coating, or using sealed vacuum packaging. However, these methods are limited by the density and adhesion of the protective layer, which is prone to peeling or failure during storage and transportation, causing the rare earth alloy to re-expose to air and oxidize, making it difficult to provide a long-lasting and stable protective effect. Some technical solutions attempt to improve oxidation resistance by optimizing the alloy composition or microstructure. For example, by controlling the distribution and structure of different phases in the alloy to improve oxidation resistance, or by adding specific elements to form a dense oxide film. However, these solutions often require the introduction of a large number of alloying elements, significantly increasing the manufacturing cost of the material, and have high requirements for composition control. In addition, some technical solutions attempt to achieve oxidation resistance through surface treatment or coating, such as chemical surface modification, coating layer preparation, or oxide film treatment. However, these methods are either complex and unsuitable for the preparation of bulk rare earth alloy modifiers, or may introduce foreign inclusions during subsequent use, affecting the purity and performance of the material. In summary, existing technologies primarily achieve oxidation resistance in rare earth alloys through physical isolation or surface coating. However, these methods are limited by the density, adhesion, and durability of the protective layer, making it difficult to fundamentally solve the intrinsic oxidation resistance problem of rare earth alloys. While some technical solutions involving alloy composition optimization or microstructure control have improved oxidation resistance to some extent, they often require the introduction of large amounts of alloying elements, increasing material costs, and fail to systematically address the oxygen penetration and diffusion issues from a crystal structure perspective. Summary of the Invention

[0005] The purpose of this invention is to provide an antioxidant rare earth alloy modifier and its preparation method. By constructing a composite crystal structure of fine surface crystals and columnar internal crystals, oxygen penetration is hindered and the oxygen diffusion barrier is increased, which significantly improves the intrinsic antioxidant performance of the rare earth alloy modifier. This solves the technical problems of physical isolation methods being not durable, high cost of component optimization, and difficulty in fundamentally inhibiting oxygen penetration in the prior art.

[0006] To solve the above-mentioned technical problems, a first aspect of the present invention provides an antioxidant rare earth alloy modifier, wherein the surface of the rare earth alloy modifier is fine-grained and the interior is columnar-shaped. The thickness of the fine-grained region on the surface is 0.1~2mm, and the grain size is 100nm~1000μm; The width of the internal columnar crystals is ≥1mm, and the area of ​​the columnar crystal region accounts for 90%~99.5%; The longitudinal grain boundaries inside the rare earth alloy modifier account for ≥95%, and the orientation deviation of the longitudinal grain boundaries is ≤25°, of which the proportion of small-angle grain boundaries below 15° is 10%~90%.

[0007] Furthermore, the rare earth alloy modifier includes rare earth elements, a base metal, and additional elements; The rare earth elements include at least one of the following: lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, lutetium, scandium, and yttrium; The base metal includes at least one of iron, copper, aluminum, magnesium, titanium, and nickel; The additional elements include at least one of chromium, molybdenum, tungsten, cobalt, manganese, vanadium, niobium, zirconium, zinc, and tin.

[0008] Furthermore, the content of the additional element in the rare earth alloy modifier is 0.05 wt.% to 15 wt.%.

[0009] Furthermore, the rare earth components include at least one of lanthanum, cerium, gadolinium, yttrium, scandium, and erbium; The additional elements include at least one of chromium, vanadium, and niobium.

[0010] Accordingly, a second aspect of the present invention provides a method for preparing an antioxidant rare earth alloy modifier, which includes the following steps: Rare earth alloy crystal rods with columnar crystals on both the surface and inside were prepared by crystal growth method; The rare earth alloy crystal rod is subjected to shot peening treatment to cause plastic deformation of the surface layer of the rare earth alloy crystal rod. The rare earth alloy crystal rods after shot peening are subjected to heat treatment in a protective atmosphere to cause recrystallization of the surface layer of the plastically deformed rare earth alloy crystal rods, forming a fine-grained layer while maintaining columnar crystals inside, thus obtaining an antioxidant rare earth alloy modifier.

[0011] Further, the surface shot peening treatment of the rare earth alloy crystal rod includes: The rare earth alloy crystal rod is subjected to surface shot peening treatment using a shot with a first preset diameter value. The shot velocity is a first preset velocity value, the shot peening angle is a first preset angle value, the shot peening coverage is >100%, and the thickness of the surface layer of the rare earth alloy crystal rod that causes plastic deformation is a first preset thickness value.

[0012] Furthermore, the numerical range of the first preset diameter value is 0.1mm to 4mm; The first preset speed value has a range of 40m / s to 120m / s; The first preset angle value has a range of 60° to 90°; The first preset thickness value has a range of 0.1mm to 2mm.

[0013] Furthermore, the projectile is made of cast steel shot, cast iron shot, or ceramic shot.

[0014] Further, the step of subjecting the shot-peened rare earth alloy crystal rod to protective atmosphere heat treatment includes: Under a preset protective atmosphere, the rare earth alloy crystal rod after shot peening is subjected to recrystallization heat treatment at a first preset temperature value and held at that temperature for a first preset time to obtain an antioxidant rare earth alloy modifier with a fine-grained surface and columnar crystals inside.

[0015] Furthermore, the numerical range of the first preset temperature value is 300℃~1200℃; The first preset duration ranges from 15 min to 120 min; The preset protective atmosphere includes at least one of argon, helium, and nitrogen.

[0016] The above-described technical solutions of the embodiments of the present invention have the following beneficial technical effects: 1. By constructing a composite crystal structure of fine surface grains and internal columnar grains, the intrinsic oxidation resistance of rare earth alloy modifiers is significantly improved by utilizing the high-density grain boundaries of the fine grain layer to block oxygen atoms and the grain boundaries of the columnar grain region along the longitudinal orientation to act as oxygen diffusion barriers. This effectively solves the problem of protection failure caused by the shedding of the protective layer in existing physical isolation methods, and greatly reduces the oxidation loss of materials during storage, transportation and use. 2. By using a crystal growth method to prepare a columnar crystal structure, combined with a process of introducing a plastic deformation layer through surface shot peening and recrystallization heat treatment to form a fine-grained surface layer, the crystal structure of rare earth alloy modifiers can be precisely controlled. This avoids the cost increase caused by adding large amounts of precious alloying elements to improve oxidation resistance, and provides an economical and feasible technical path for preparing high-performance rare earth alloy modifiers. 3. By optimizing the internal grain boundary characteristics of rare earth alloy modifiers, the proportion of longitudinal grain boundaries reaches over 95% and the proportion of small-angle grain boundaries is controlled. While maintaining the excellent mechanical properties of the material, the rapid penetration of oxygen into the material interior along the transverse grain boundaries is effectively suppressed. This reduces the risk of introducing foreign oxide inclusions into the metal melt during the use of rare earth alloy modifiers, thereby ensuring the smoothness of the metal material preparation process and the uniformity of the final product's microstructure. Attached Figure Description

[0017] Figure 1 This is a flowchart of the method for preparing antioxidant rare earth alloy modifiers provided in the embodiments of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0019] The first aspect of this invention provides an antioxidant rare earth alloy modifier, wherein the surface layer of the rare earth alloy modifier is fine-grained and the interior is columnar crystals; the thickness of the fine-grained region on the surface is 0.1~2mm, and the grain size is 100nm~1000μm; the width of the columnar crystals inside is ≥1mm, and the area of ​​the columnar crystal region accounts for 90%~99.5%; the proportion of longitudinal grain boundaries inside the rare earth alloy modifier is ≥95%, the orientation deviation of the longitudinal grain boundaries is ≤25°, and the proportion of small-angle grain boundaries below 15° is 10%~90%.

[0020] The aforementioned rare earth alloy modifiers address the oxidation resistance problem of rare earth alloys from the perspective of intrinsic material properties by constructing a composite crystal structure of fine-grained surface and columnar internal crystals. The penetration and diffusion behavior of oxygen in metallic materials strongly depends on the grain boundary structure: the fine-grained surface layer has a high density of grain boundaries, which effectively adsorb and hinder oxygen atoms from penetrating the material interior, forming the first physical barrier; while the internal columnar crystal structure, due to its fewer grain boundaries and their longitudinal orientation, exhibits a high proportion of longitudinal and small-angle grain boundaries, reducing grain boundary energy and oxygen diffusion rate, and further significantly inhibiting the rate of oxygen diffusion into the grains, thus constructing a second diffusion barrier within the material. This synergistic effect of internal and external grain boundaries fundamentally inhibits oxygen penetration into the material interior, thereby improving the intrinsic oxidation resistance.

[0021] The width of the internal columnar crystals refers to the transverse dimension of the columnar crystal structure within the rare earth alloy modifier on the longitudinal section. It characterizes the coarseness of the columnar crystals, and its value directly affects the number of grain boundaries and the path length for oxygen diffusion along the grain boundaries. The percentage of columnar crystal area refers to the percentage of the area occupied by the columnar crystal structure in the cross-section or longitudinal section of the rare earth alloy modifier relative to the total observed area. It is used to quantitatively describe the area fraction and uniformity of columnar crystal distribution throughout the material. Longitudinal grain boundaries refer to grain boundaries parallel to the crystal growth direction or the axis of the columnar crystals. Their proportion and orientation characteristics determine the diffusion path and resistance magnitude for oxygen penetration into the material along the grain boundaries.

[0022] Regarding parameter settings, this invention defines various characteristics of the composite crystal structure: the thickness of the surface fine-grained region is controlled at 0.1~2mm, ensuring a sufficiently thick dense layer to block oxygen while avoiding excessive thickness that could affect the overall material performance; the grain size is set at 100nm~1000μm, ensuring the fine-grained layer has high-density grain boundaries while maintaining structural stability. The internal columnar crystals have a width ≥1mm and an area ratio of 90%~99.5%, ensuring a highly oriented columnar crystal structure in the main body of the material and minimizing transverse grain boundaries; the longitudinal grain boundaries account for ≥95% and have an orientation deviation ≤25°, ensuring consistent axial height of the grain boundaries and significantly improving the resistance to oxygen diffusion along the grain boundaries; in particular, the setting of 10%~90% for small-angle grain boundaries below 15° utilizes the low energy and small diffusion coefficient of small-angle grain boundaries to further enhance the oxidation resistance of the internal structure. The synergistic design of these parameters enables the material to possess excellent oxygen barrier capabilities at different scales.

[0023] After being stored at room temperature for 15 days, the surface and internal oxygen content of the rare earth alloy modifier can be as low as 45-70 ppm and 20-50 ppm, respectively, far superior to the 100-250 ppm level of similar products. In practical applications, adding this modifier to molten steel for rare earth treatment significantly increases the rare earth yield from 25%-35% to 80%-96%, significantly reduces the average size of inclusions in the steel, and improves the success rate of continuous casting from one heat with poor flow to four to five heats with good flow. Therefore, the composite crystal structure design of this invention not only effectively reduces the oxidation loss of the modifier itself during storage and transportation, but more importantly, it avoids the introduction of foreign rare earth oxide inclusions during use, thus ensuring the smooth operation of the metallurgical process and the uniformity of the final product's microstructure, truly achieving the efficient utilization and stable function of rare earth elements.

[0024] In one embodiment of the present invention, the rare earth alloy modifier includes rare earth elements, a base metal, and additional elements.

[0025] In one embodiment of the present invention, the rare earth element in the rare earth alloy modifier can be selected from at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, lutetium, scandium, and yttrium. Preferably, the rare earth component includes at least one of lanthanum, cerium, gadolinium, yttrium, scandium, and erbium. The above elements cover a wide range from light rare earths to heavy rare earths. Among them, light rare earth elements such as lanthanum and cerium are abundant and relatively inexpensive, making them suitable for large-scale industrial applications; heavy rare earth elements such as yttrium and scandium, although more expensive, have a more significant lattice distortion effect and stronger oxide modification ability. Different rare earth elements have different focuses in the alloy, and can play a role in purifying the melt and refining the microstructure as the main modifier elements, or achieve a synergistic effect through the composite addition of multiple rare earths. Those skilled in the art can flexibly select and combine rare earth elements according to specific application scenarios to meet the differentiated requirements of different metal melt processing for the performance of modifiers.

[0026] The base metal includes at least one of iron, copper, aluminum, magnesium, titanium, and nickel. As a carrier and diluent for rare earth elements, the choice of base metal directly affects the melting point, density, and compatibility of the modifier with the molten metal to be treated. Iron-based rare earth ferroalloys have good affinity with steel materials and are particularly suitable for rare earth treatment in the steel metallurgy field. Copper, aluminum, magnesium, and titanium-based rare earth alloys are more suitable for modifying non-ferrous alloys. Nickel-based rare earth alloys have unique advantages in high-temperature alloys and stainless steel. By rationally selecting the base metal, it can be ensured that the rare earth alloy modifier can quickly melt and uniformly disperse after being added to the melt, maximizing the modifying effect of rare earth elements while avoiding segregation and floating problems caused by excessive density differences or melting point mismatches.

[0027] Optional additional elements include at least one of chromium, molybdenum, tungsten, cobalt, manganese, vanadium, niobium, zirconium, zinc, and tin; preferably, additional elements include at least one of chromium, vanadium, and niobium. The introduction of additional elements can further optimize the overall performance of the modifier. For example, chromium can improve the corrosion resistance of the alloy, molybdenum and tungsten can enhance high-temperature strength, niobium and zirconium are strong carbide-forming elements that help refine grains, and zinc can improve the fluidity of the alloy. The amount and combination of additional elements need to be specifically designed according to the compositional characteristics and performance requirements of the target metallic material. Through micro-alloying, the performance of the modifier can be directionally controlled without significantly increasing costs, thereby better meeting the diverse needs of different metallurgical processes and application scenarios.

[0028] Furthermore, the content of the added elements in the rare earth alloy modifier is 0.05 wt.% to 15 wt.%. This numerical range reflects a precise consideration of the alloy composition design: from the lower limit, 0.05 wt.% is the starting threshold for the added elements to play an effective role. When the addition amount is below this value, the added elements are difficult to form effective solid solution strengthening or microstructure control in the alloy, and the resulting microalloying effect is negligible. They are usually regarded as unavoidable impurities rather than intentionally added alloying elements. From the upper limit, 15 wt.% is the upper limit of the addition of added elements under the premise of ensuring the main characteristics of the rare earth alloy matrix. When the addition amount exceeds this value, the added elements may begin to change the basic phase composition and crystal structure of the alloy, resulting in excessive dilution of the relative content of rare earth elements, thereby weakening the core function of the modifier.

[0029] Accordingly, please refer to Figure 1 The second aspect of this invention provides a method for preparing an antioxidant rare earth alloy modifier, which includes the following steps: Step S100: A rare earth alloy crystal rod with columnar crystals on both the surface and inside is prepared by crystal growth method.

[0030] After preparing the raw materials according to the weight ratio of each component in the antioxidant rare earth alloy material, the base metal, rare earth metal, and auxiliary element raw materials are placed in the induction melting crucible of the crystal growth furnace. The crucible is an alumina crucible, a magnesium oxide crucible, a calcium oxide crucible, a tungsten crucible, a niobium crucible, or a molybdenum crucible. The furnace lid is then closed, and a vacuum is drawn to below 0.6 Pa. Argon gas is introduced at 0.01 MPa to 0.04 MPa, and the furnace is cleaned twice. After cleaning, the melting stage begins. Argon gas is introduced to maintain the vacuum in the crystal growth furnace at 0.01 MPa to 0.04 MPa. The heating system is turned on, and the rare earth alloy modifier raw materials are slowly heated to melt, resulting in a melt surface superheat of 5°C to 50°C. After melting, crystal pulling is performed. The rare earth alloy modifier seed crystal is lowered and preheated for 30 to 60 minutes, then the seed crystal is introduced into the melt for welding. After crystal pulling, necking is performed at 3 mm / m. The seed crystal is rapidly raised at a speed of 10 mm / min to draw out a neck of a certain length and a diameter of 3 mm to 5 mm. After necking, the shoulder-forming stage begins, with the pulling speed reduced to 0.2 mm / min to 8 mm / min, allowing the diameter of the rare earth alloy modifier crystal to gradually increase to 10 mm to 500 mm. When the crystal reaches the target diameter, the shoulder is formed, and the pulling speed and temperature are appropriately increased to stop the crystal diameter from growing, and the crystal enters a stable, constant-diameter growth stage. Subsequently, the constant-diameter stage is entered, where the pulling speed and temperature are continuously adjusted using a PID program to keep the fluctuation of the rare earth alloy modifier crystal diameter within a certain error range. Finally, to avoid leaving a large amount of rare earth alloy modifier melt in the crucible, the pulling speed and temperature are increased before the pulling ends to slowly reduce the crystal diameter until all the melt in the crucible is pulled out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0031] Besides the Czochralski method based on induction melting mentioned above, those skilled in the art can also use other crystal growth techniques capable of directional solidification or single crystal growth to prepare rare earth alloy rods with columnar crystals on both the surface and inside. For example, zone melting (including suspension zone melting and horizontal zone melting) uses a moving heating zone to directionally solidify the molten zone, which can also obtain columnar crystal structures with significant axial orientation. In addition, the Bridgman method, which slowly cools the melt under a temperature gradient to allow crystals to grow directionally along the heat flow direction, is also a common method for preparing columnar or single crystal materials. Any rare earth alloy rod with internal columnar crystal structure characteristics obtained by any of the above crystal growth methods can be used as a substrate for subsequent shot peening and heat treatment processes, thus falling within the protection scope of this invention. Those skilled in the art should understand that the specific process for obtaining a fully columnar crystal structure is not the core innovation of this invention; as long as the specific crystal structure can be achieved, it should be considered an equivalent embodiment of this invention.

[0032] Step S200: The rare earth alloy crystal rod is subjected to shot peening treatment to cause plastic deformation of the surface layer of the rare earth alloy crystal rod.

[0033] Rare earth alloy crystal rods are subjected to shot peening to induce plastic deformation on the surface. High-speed shot continuously impacts the surface of the crystal rod, introducing a layer of intense plastic deformation in the surface region. Within this deformation layer, the grains fragment and store a large amount of deformation energy, while the columnar crystalline structure in the internal region of the crystal rod is preserved intact. This results in a microstructure state where a deformed surface region and an undeformed internal region coexist within a single material.

[0034] Step S300: The rare earth alloy crystal rod after shot peening is subjected to heat treatment in a protective atmosphere to recrystallize the surface of the plastically deformed rare earth alloy crystal rod to form a fine-grained layer, while the interior retains columnar crystals, thus obtaining an antioxidant rare earth alloy modifier.

[0035] Rare earth alloy ingots that have undergone shot peening are then subjected to heat treatment in a protective atmosphere. This process causes recrystallization of the surface layer of the plastically deformed rare earth alloy ingots, forming a fine-grained layer, while the interior retains columnar crystals, resulting in an antioxidant rare earth alloy modifier. Heating the ingots in a protective atmosphere causes the deformed surface region to recrystallize under thermal activation, forming a uniform and fine equiaxed crystal structure. Meanwhile, the undeformed columnar crystal region inside, lacking the driving force for recrystallization, retains its original crystal structure intact. This ultimately yields a composite crystal structure with a fine-grained surface and columnar interior, significantly improving the material's intrinsic oxidation resistance.

[0036] In one specific embodiment of the present invention, the surface shot peening treatment of the rare earth alloy crystal rod in step S200 includes: When performing shot peening on rare earth alloy crystal rods, shot with a diameter of a first preset diameter value is selected. Optionally, the range of the first preset diameter value is 0.1 mm to 4 mm. The selection of this diameter parameter directly determines the magnitude of the contact stress and energy transfer efficiency generated when the shot impacts the surface of the crystal rod, and is a key factor in controlling the thickness and deformation uniformity of the surface plastic deformation layer. By reasonably setting the shot diameter range, it is ensured that the shot has sufficient mass and kinetic energy to introduce a uniform plastic deformation layer on the surface of the crystal rod, while avoiding excessive surface damage or microcracks caused by excessively large shot, thus providing an ideal deformation structure basis for the subsequent recrystallization heat treatment to form a complete fine-grained layer.

[0037] During shot peening, the shot is propelled at a high speed to the surface of the crystal rod at a first preset velocity value and impacts the crystal rod at a first preset angle value. The coordinated control of these two parameters is key to achieving controllable plastic deformation of the surface layer. Optionally, the first preset velocity value ranges from 40 m / s to 120 m / s; the first preset angle value ranges from 60° to 90°. The shot velocity determines the magnitude of the impact kinetic energy, directly affecting the depth and degree of plastic deformation of the layer; the shot peening angle affects the ratio of the normal to tangential components of the shot impact energy, thus influencing the deformation mode and residual stress distribution of the surface material. By controlling the velocity within the range of 40 m / s to 120 m / s and the angle within the range of 60° to 90°, a uniform and sufficiently deep plastic deformation zone can be obtained on the surface of the crystal rod, providing sufficient deformation energy for subsequent recrystallization while ensuring the integrity of the deformation layer and avoiding surface scratches or decreased energy utilization due to excessively small angles.

[0038] In this embodiment, the shot peening coverage is controlled to be greater than 100%, meaning that the surface of the crystal rod is not only completely covered by the craters once, but also undergoes over-peening after achieving 100% coverage. In the field of shot peening strengthening technology, a coverage rate >100% represents the saturation degree of the shot peening treatment, that is, the shot peening time reaches or exceeds a multiple of the time required to achieve complete coverage. By adopting the over-peening process, more plastic deformation energy and a deeper deformation-affected zone can be accumulated on the surface, ensuring that the material undergoes sufficient plastic deformation throughout the entire target depth range. This avoids insufficient local deformation or uneven deformation layer thickness due to uneven coverage, thereby providing a guarantee for the formation of a continuous and uniform fine-grained layer during subsequent heat treatment.

[0039] The thickness of the surface layer of the rare earth alloy crystal rod undergoing plastic deformation is a first preset thickness value; optionally, the first preset thickness value ranges from 0.1 mm to 2 mm. The thickness of this plastically deformed layer directly determines the final thickness of the fine-grained region and is a key process parameter for achieving the composite structure of "surface fine grains + internal columnar grains". By controlling the thickness of the deformed layer within the range of 0.1 mm to 2 mm, a fine-grained structure matching the thickness of the fine-grained region described in claim 1 can be formed after subsequent recrystallization heat treatment. This ensures that the surface layer has a sufficiently thick fine-grained layer to effectively block oxygen penetration while avoiding damage to the internal columnar grain structure due to excessively deep deformed layers, thereby achieving an optimal balance between improving oxidation resistance and preserving the matrix structure.

[0040] Optionally, the shot can be made of cast steel shot, cast iron shot, or ceramic shot. Different materials have their own advantages. Cast steel and cast iron shot have high density and good wear resistance, providing high impact kinetic energy, making them suitable for processes requiring large deformation. Ceramic shot, on the other hand, has higher hardness and a longer service life, and is less prone to breakage and contamination of the crystal rod surface during impact. Regardless of the material chosen, it is essential to ensure that the shot maintains its shape during high-speed impact, preventing the introduction of impurities into the crystal rod surface, thereby guaranteeing the purity of the rare earth alloy modifier and the performance of the final product.

[0041] Specifically, step S300, which involves subjecting the shot-peened rare-earth alloy crystal rod to protective atmosphere heat treatment, includes: Under a preset protective atmosphere, the rare earth alloy crystal rod after shot peening is subjected to recrystallization heat treatment at a first preset temperature value and held at that temperature for a first preset time to obtain an antioxidant rare earth alloy modifier with a fine-grained surface and columnar crystals inside.

[0042] Optionally, the first preset temperature value ranges from 300℃ to 1200℃. This temperature parameter directly determines whether the surface deformation zone can undergo sufficient recrystallization, and is a core controlling factor for the formation of a fine-grained layer. When the heat treatment temperature reaches the recrystallization threshold, the deformation energy stored in the surface deformation zone is released, forming new fine equiaxed grains through grain boundary migration and dislocation reorganization. If the temperature is too low, the recrystallization process cannot be activated, and the deformed structure is preserved; if the temperature is too high, excessive grain growth may occur, resulting in a loss of the fine-grained strengthening effect. By controlling the temperature within the range of 300℃ to 1200℃, adaptive adjustments can be made according to the recrystallization characteristics of the specific alloy system, ensuring complete recrystallization of the surface deformation zone to form a uniform fine-grained structure, while avoiding unnecessary phase transformations or grain coarsening in the internal columnar crystal regions.

[0043] Optionally, the first preset time ranges from 15 min to 120 min. This first preset time works in conjunction with the heat treatment temperature to jointly determine the degree of completion of the recrystallization process and the final grain size. Under the premise of reaching the recrystallization temperature, sufficient holding time is required to allow the recrystallization nucleation and grain growth processes within the deformation zone to fully proceed, forming a stable and uniform fine-grained structure. Too short a holding time may lead to incomplete recrystallization, leaving some deformed structure residue, affecting the integrity and oxidation resistance of the fine-grained layer; too long a holding time may cause excessive grain growth, weakening the oxygen barrier effect of the fine-grained layer. By controlling the holding time within the range of 15 min to 120 min, it is possible to ensure sufficient recrystallization while controlling the grain size within the target range, obtaining a microstructure that matches the grain size of the fine-grained zone.

[0044] Optionally, the preset protective atmosphere includes at least one of argon, helium, and nitrogen. Rare earth alloys have extremely high chemical reactivity and readily react with elements such as oxygen in the air during high-temperature heat treatment, leading to surface oxidation or component contamination, which compromises the purity and subsequent performance of the material. By introducing an inert protective atmosphere, harmful atmospheres in the heat treatment environment can be effectively isolated, ensuring that the surface of the crystal rod does not undergo oxidation during recrystallization, thus maintaining the intrinsic composition and purity of the material. Argon, as a commonly used inert protective gas, has the advantages of high density, good protective effect, and moderate cost; helium has high thermal conductivity and is suitable for scenarios requiring rapid and uniform heating; nitrogen can be used as an economical protective atmosphere in certain alloy systems. By selecting a suitable combination of one or more gases, optimal control of process costs can be achieved while ensuring the heat treatment effect.

[0045] The preparation method described above will be further illustrated below with several examples and comparative examples: Example 1 A method for preparing an antioxidant La-Fe alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: lanthanum and iron were 5 wt.% and 95 wt.%, respectively, with the lanthanum having a purity of 99.9% and the iron having a purity of 99.5%. The lanthanum and iron were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.01 MPa, and the furnace was cleaned twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.01 MPa argon gas. The power was then slowly increased until the iron and lanthanum blocks were completely melted, maintaining a superheat of 5°C on the solution surface. The rare earth alloy modifier seed crystal was then lowered for preheating for 30 minutes before being introduced into the melt for welding. The seed crystal was then rapidly raised at 3 mm / min to create a 20 mm long, 3 mm diameter neck. After necking, the pulling speed was reduced to 0.2 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 500 mm. Then, the pulling speed was increased to 0.4 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare-earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 1 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare-earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0046] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.1 mm, a blasting speed of 40 m / s, a blasting angle of 60°, and a shot peening coverage of 100%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.1 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 300℃ for 15 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 100 nm, the thickness of the fine-grained region was 0.1 mm, the width of the internal longitudinal columnar crystals was 20 mm, and the proportion of small-angle grain boundaries was 90%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 45 ppm, and the oxygen content internally was 20 ppm.

[0047] Example 2 A method for preparing an antioxidant Ce-Fe alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their weight percentages: cerium and iron were 10 wt.% and 90 wt.%, respectively, with the cerium having a purity of 99.9% and the iron having a purity of 99.5%. The cerium and iron were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was cleaned twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.02 MPa argon gas. The power was then slowly increased until the iron and cerium blocks were completely melted, maintaining a superheat of 10°C on the solution surface. The rare earth alloy modifier seed crystal was then lowered for preheating for 40 minutes before being introduced into the melt for welding. The seed crystal was then rapidly raised at a speed of 4 mm / min to create a 20 mm long, 4 mm diameter neck. After necking, the pulling speed was reduced to 1 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 450 mm. Then, the pulling speed was increased to 1.2 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 6 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0048] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.5 mm, a blasting speed of 60 m / s, a blasting angle of 70°, and a shot peening coverage of 120%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.5 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 400℃ for 30 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 100 μm, the thickness of the fine-grained region was 0.5 mm, the width of the internal longitudinal columnar crystals was 15 mm, and the proportion of small-angle grain boundaries was 70%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 50 ppm, and the oxygen content internally was 30 ppm.

[0049] Example 3 A method for preparing an antioxidant Gd-Fe alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: gadolinium metal 15 wt.% and iron metal 85 wt.%, with gadolinium metal having a purity of 99.9% and iron metal having a purity of 99.5%. Place the gadolinium metal and iron metal into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.04 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 5 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the iron and gadolinium blocks are completely melted, maintaining a superheat of 20°C on the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 50 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 5 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 400 mm. The pulling speed is then increased to 2.3 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the pulling speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0050] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 1 mm, a blasting speed of 80 m / s, a blasting angle of 80°, and a shot peening coverage of 130%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a nitrogen-protected heat treatment furnace at a recrystallization temperature of 500℃ for 45 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 150 μm, the thickness of the fine-grained region was 1 mm, the width of the internal longitudinal columnar crystals was 13 mm, and the proportion of small-angle grain boundaries was 65%. After being placed under ambient atmospheric conditions for 15 days, the oxygen content on the surface of the rods was 54 ppm, and the oxygen content internally was 32 ppm.

[0051] Example 4 A method for preparing an antioxidant Y-Fe alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: yttrium and iron are 20 wt.% and 80 wt.%, respectively, with the yttrium having a purity of 99.9% and the iron having a purity of 99.5%. Place the yttrium and iron raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.03 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 5 minutes, introduce 0.03 MPa argon gas, then slowly increase the power until the iron and yttrium blocks are completely melted, maintaining a superheat of 30°C at the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 60 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 3 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 350 mm. The drawing speed is then increased to 3.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Towards the end of the crystal growth stage, the drawing speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0052] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 2 mm, a blasting speed of 90 m / s, a blasting angle of 90°, and a shot peening coverage of 150%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.5 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 600℃ for 60 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 200 μm, the thickness of the fine-grained region was 1.5 mm, the width of the internal longitudinal columnar crystals was 10 mm, and the proportion of small-angle grain boundaries was 40%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 57 ppm, and the oxygen content internally was 35 ppm.

[0053] Example 5 A method for preparing an antioxidant Sc-Fe alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: scandium metal 25 wt.% and iron metal 75 wt.%, with scandium metal purity of 99.9% and iron metal raw material purity of 99.5%. Place the yttrium metal and iron metal raw material into the induction melting crucible of the crystal growth furnace. After evacuating the furnace to a vacuum level below 0.6 Pa, introduce 0.04 MPa argon gas and repeat the furnace cleaning twice. After baking the furnace at low power for 10 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the iron and scandium blocks in the furnace are completely melted, maintaining the superheat of the solution surface at 40°C. Then, lower the rare earth alloy modifier seed crystal for preheating for 40 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 7 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 4 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 300 mm. The pulling speed is then increased to 4.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Towards the end of the crystal growth stage, the pulling speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0054] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 3 mm, a blasting speed of 100 m / s, a blasting angle of 90°, and a shot peening coverage of 170%. This resulted in rare earth alloy modifier rods with plastic deformation within a 2 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 500℃ for 70 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 400 μm, the thickness of the fine-grained region was 2 mm, the width of the internal longitudinal columnar crystals was 8 mm, and the proportion of small-angle grain boundaries was 20%. After being placed under ambient atmospheric conditions for 15 days, the oxygen content on the surface of the rods was 63 ppm, and the oxygen content internally was 40 ppm.

[0055] Example 6 A method for preparing an antioxidant Er-Fe alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: erbium metal 30 wt.% and iron metal 70 wt.%, with erbium metal purity of 99.9% and iron metal purity of 99.5%. Place the erbium metal and iron metal into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce argon gas at 0.04 MPa and repeat the furnace cleaning twice. After baking the furnace at low power for 10 minutes, introduce argon gas at 0.04 MPa, then slowly increase the power until the iron and erbium blocks in the furnace are completely melted, maintaining the superheat of the solution surface at 50°C. Then, lower the rare earth alloy modifier seed crystal for preheating for 60 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 10 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 4 mm. After necking, the drawing speed is reduced to 8 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 10 mm. The drawing speed is then increased to 8.2 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0056] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 4 mm, a blasting speed of 120 m / s, a blasting angle of 90°, and a shot peening coverage of 180%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 2 mm surface layer, while the internal structure remained columnar. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 600℃ for 80 min, followed by water quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 1000 μm, the thickness of the fine-grained region was 2 mm, the width of the internal longitudinal columnar crystals was 1 mm, and the proportion of small-angle grain boundaries was 10%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 70 ppm, and the oxygen content inside was 50 ppm.

[0057] Example 7 A method for preparing an antioxidant La-Cu alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: lanthanum and copper were 5 wt.% and 95 wt.%, respectively, with the lanthanum having a purity of 99.9% and the copper having a purity of 99.5%. The lanthanum and copper were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.01 MPa, and the furnace was cleaned twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.01 MPa argon gas. The power was then slowly increased until the copper and lanthanum blocks were completely melted, maintaining a superheat of 5°C on the solution surface. The rare earth alloy modifier seed crystal was then lowered for preheating for 30 minutes before being introduced into the melt for welding. The seed crystal was then rapidly raised at 3 mm / min to create a 20 mm long, 3 mm diameter neck. After necking, the pulling speed was reduced to 0.2 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 500 mm. Then, the pulling speed was increased to 0.4 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare-earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 1 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare-earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0058] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.1 mm, a blasting speed of 40 m / s, a blasting angle of 60°, and a shot peening coverage of 100%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.1 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 300℃ for 15 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 100 nm, the thickness of the fine-grained region was 0.1 mm, the width of the internal longitudinal columnar crystals was 20 mm, and the proportion of small-angle grain boundaries was 90%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 45 ppm, and the oxygen content internally was 20 ppm.

[0059] Example 8 A method for preparing an antioxidant Ce-Cu alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their weight percentages: cerium and copper were 10 wt.% and 90 wt.%, respectively, with the cerium having a purity of 99.9% and the copper having a purity of 99.5%. The cerium and copper raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was cleaned twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.02 MPa argon gas. The power was then slowly increased until the copper and cerium blocks were completely melted, maintaining a superheat of 10°C on the solution surface. The rare earth alloy modifier seed crystal was then lowered and preheated for 40 minutes before being introduced into the melt for welding. The seed crystal was then rapidly raised at a speed of 4 mm / min to create a 20 mm long, 4 mm diameter neck. After necking, the pulling speed was reduced to 1 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 450 mm. Then, the pulling speed was increased to 1.2 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 6 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0060] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.5 mm, a blasting speed of 60 m / s, a blasting angle of 70°, and a shot peening coverage of 120%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.5 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 400℃ for 30 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 100 μm, the thickness of the fine-grained region was 0.5 mm, the width of the internal longitudinal columnar crystals was 15 mm, and the proportion of small-angle grain boundaries was 70%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 50 ppm, and the oxygen content internally was 30 ppm.

[0061] Example 9 A method for preparing an antioxidant Gd-Cu alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their weight percentages: gadolinium and copper were 15 wt.% and 85 wt.%, respectively, with the gadolinium having a purity of 99.9% and the copper having a purity of 99.5%. The gadolinium and copper were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.04 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.04 MPa argon gas. The power was then slowly increased until the copper and gadolinium blocks were completely melted, maintaining a superheat of 20°C at the solution surface. A rare earth alloy modifier seed crystal was then lowered for preheating for 50 minutes before being introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 5 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 400 mm. The pulling speed is then increased to 2.3 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the pulling speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0062] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 1 mm, a blasting speed of 80 m / s, a blasting angle of 80°, and a shot peening coverage of 130%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a nitrogen-protected heat treatment furnace at a recrystallization temperature of 500℃ for 45 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 150 μm, the thickness of the fine-grained region was 1 mm, the width of the internal longitudinal columnar crystals was 13 mm, and the proportion of small-angle grain boundaries was 65%. After being placed under ambient atmospheric conditions for 15 days, the oxygen content on the surface of the rods was 54 ppm, and the oxygen content internally was 32 ppm.

[0063] Example 10 A method for preparing an antioxidant Y-Cu alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: yttrium and copper are 20 wt.% and 80 wt.%, respectively, with the yttrium having a purity of 99.9% and the copper having a purity of 99.5%. Place the yttrium and copper raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.03 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 5 minutes, introduce 0.03 MPa argon gas, then slowly increase the power until the copper and yttrium blocks are completely melted, maintaining a superheat of 30°C at the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 60 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 3 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 350 mm. The drawing speed is then increased to 3.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Towards the end of the crystal growth stage, the drawing speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0064] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 2 mm, a blasting speed of 90 m / s, a blasting angle of 90°, and a shot peening coverage of 150%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.5 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 600℃ for 60 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 200 μm, the thickness of the fine-grained region was 1.5 mm, the width of the internal longitudinal columnar crystals was 10 mm, and the proportion of small-angle grain boundaries was 63%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 57 ppm, and the oxygen content internally was 35 ppm.

[0065] Example 11 A method for preparing an antioxidant Sc-Cu alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: scandium metal 25 wt.% and copper metal 75 wt.%, with scandium metal purity of 99.9% and copper metal raw material purity of 99.5%. Place the scandium metal and copper metal raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.04 MPa argon gas and repeat the furnace cleaning twice. After baking the furnace at low power for 10 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the iron and scandium blocks in the furnace are completely melted, maintaining the solution surface temperature superheat at 40°C. Then, lower the rare earth alloy modifier seed crystal for preheating for 40 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 7 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 4 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 100 mm. The drawing speed is then increased to 4.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Towards the end of the crystal growth stage, the drawing speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0066] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 3 mm, a blasting speed of 100 m / s, a blasting angle of 90°, and a shot peening coverage of 170%. This resulted in rare earth alloy modifier rods with plastic deformation within a 2 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 500℃ for 70 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 400 μm, the thickness of the fine-grained region was 2 mm, the width of the internal longitudinal columnar crystals was 8 mm, and the proportion of small-angle grain boundaries was 60%. After being placed under ambient atmospheric conditions for 15 days, the oxygen content on the surface of the rods was 63 ppm, and the oxygen content internally was 40 ppm.

[0067] Example 12 A method for preparing an antioxidant Er-Cu alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: erbium metal 30 wt.% and copper metal 70 wt.%, with erbium purity of 99.9% and copper purity of 99.5%. Place the erbium metal and copper metal into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.04 MPa argon gas and repeat the furnace cleaning twice. After baking the furnace at low power for 10 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the copper and erbium blocks are completely melted, maintaining the solution surface temperature superheat at 50°C. Then, lower the rare earth alloy modifier seed crystal for preheating for 50 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 10 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 8 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 50 mm. The pulling speed is then increased to 8.1 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the pulling speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0068] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 4 mm, a blasting speed of 120 m / s, a blasting angle of 90°, and a shot peening coverage of 180%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 2 mm surface layer, while the internal structure remained columnar. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 600℃ for 80 min, followed by water quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 1000 μm, the thickness of the fine-grained region was 2 mm, the width of the internal longitudinal columnar crystals was 2 mm, and the proportion of small-angle grain boundaries was 30%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 70 ppm, and the oxygen content inside was 50 ppm.

[0069] Example 13 A method for preparing an antioxidant La-Al alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: lanthanum and aluminum were 5 wt.% and 95 wt.%, respectively, with the lanthanum having a purity of 99.9% and the aluminum having a purity of 99.5%. The lanthanum and aluminum were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.01 MPa, and the furnace was cleaned twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.01 MPa argon gas. The power was then slowly increased until the aluminum and lanthanum blocks were completely melted, maintaining a superheat of 5°C on the solution surface. The rare earth alloy modifier seed crystal was then lowered for preheating for 30 minutes before being introduced into the melt for welding. The seed crystal was then rapidly raised at 3 mm / min to create a 20 mm long, 3 mm diameter neck. After necking, the pulling speed was reduced to 0.2 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 500 mm. Then, the pulling speed was increased to 0.4 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare-earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 1 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare-earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0070] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.1 mm, a blasting speed of 40 m / s, a blasting angle of 60°, and a shot peening coverage of 100%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.1 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 300℃ for 15 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 130 nm, the thickness of the fine-grained region was 0.1 mm, the width of the internal longitudinal columnar crystals was 20 mm, and the proportion of small-angle grain boundaries was 90%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 45 ppm, and the oxygen content internally was 20 ppm.

[0071] Example 14 A method for preparing an antioxidant Ce-Al alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: cerium and aluminum were 10 wt.% and 90 wt.%, respectively, with the cerium having a purity of 99.9% and the aluminum having a purity of 99.5%. The cerium and aluminum were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was cleaned twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.02 MPa argon gas. The power was then slowly increased until the aluminum and cerium blocks were completely melted, maintaining a superheat of 10°C on the solution surface. The rare earth alloy modifier seed crystal was then lowered and preheated for 40 minutes before being introduced into the melt for welding. The seed crystal was then rapidly raised at a speed of 4 mm / min to create a 20 mm long, 4 mm diameter neck. After necking, the pulling speed was reduced to 1 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 450 mm. Then, the pulling speed was increased to 1.2 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 6 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0072] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.5 mm, a blasting speed of 60 m / s, a blasting angle of 70°, and a shot peening coverage of 120%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.5 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 400℃ for 30 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 100 μm, the thickness of the fine-grained region was 0.5 mm, the width of the internal longitudinal columnar crystals was 15 mm, and the proportion of small-angle grain boundaries was 70%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 50 ppm, and the oxygen content internally was 30 ppm.

[0073] Example 15 A method for preparing an antioxidant Gd-Al alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: gadolinium and aluminum are 15 wt.% and 85 wt.%, respectively, with gadolinium having a purity of 99.9% and aluminum having a purity of 99.5%. Place the gadolinium and aluminum raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.04 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 5 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the aluminum and gadolinium blocks are completely melted, maintaining a superheat of 20°C at the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 50 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 5 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 400 mm. The pulling speed is then increased to 2.3 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the pulling speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0074] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 1 mm, a blasting speed of 80 m / s, a blasting angle of 80°, and a shot peening coverage of 130%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 1 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a nitrogen-protected heat treatment furnace at a recrystallization temperature of 350°C for 45 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 150 μm, the thickness of the fine-grained region was 1 mm, the width of the internal longitudinal columnar crystals was 13 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 54 ppm, and the oxygen content internally was 32 ppm.

[0075] Example 16 A method for preparing an antioxidant Y-Al alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: yttrium and aluminum are 20 wt.% and 80 wt.%, respectively, with the yttrium having a purity of 99.9% and the aluminum having a purity of 99.5%. Place the yttrium and aluminum raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.03 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 5 minutes, introduce 0.03 MPa argon gas, then slowly increase the power until the aluminum and yttrium blocks are completely melted, maintaining a superheat of 30°C at the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 60 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 3 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 25 mm. The pulling speed is then increased to 3.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the pulling speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0076] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 2 mm, a blasting speed of 90 m / s, a blasting angle of 90°, and a shot peening coverage of 150%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.5 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 600℃ for 60 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 200 μm, the thickness of the fine-grained region was 1.5 mm, the width of the internal longitudinal columnar crystals was 10 mm, and the proportion of small-angle grain boundaries was 63%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 57 ppm, and the oxygen content internally was 35 ppm.

[0077] Example 17 A method for preparing an antioxidant Sc-Al alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: scandium metal 25 wt.% and aluminum metal 75 wt.%, with scandium metal purity of 99.9% and aluminum metal raw material purity of 99.5%. Place the scandium metal and aluminum metal raw material into the induction melting crucible of the crystal growth furnace. After evacuating the furnace to a vacuum level below 0.6 Pa, introduce 0.04 MPa argon gas and repeat the furnace cleaning twice. After baking the furnace at low power for 10 minutes, introduce 0.04 MPa argon gas, and then slowly increase the power until the aluminum and scandium blocks in the furnace are completely melted, maintaining the superheat of the solution surface at 40°C. Then, lower the rare earth alloy modifier seed crystal for preheating for 40 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 7 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 4 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 100 mm. The drawing speed is then increased to 4.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Towards the end of the crystal growth stage, the drawing speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0078] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 3 mm, a blasting speed of 100 m / s, a blasting angle of 90°, and a shot peening coverage of 170%. This resulted in rare earth alloy modifier rods with plastic deformation within a 2 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 450℃ for 70 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 400 μm, the thickness of the fine-grained region was 2 mm, the width of the internal longitudinal columnar crystals was 8 mm, and the proportion of small-angle grain boundaries was 60%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 63 ppm, and the oxygen content internally was 40 ppm.

[0079] Example 18 A method for preparing an antioxidant Er-Al alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: erbium metal 30 wt.% and aluminum metal 70 wt.%, with erbium metal purity of 99.9% and aluminum metal purity of 99.5%. Place the erbium metal and aluminum metal into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.04 MPa argon gas and repeat the furnace cleaning twice. After baking the furnace at low power for 10 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the aluminum and erbium blocks in the furnace are completely melted, maintaining the superheat of the solution surface at 50°C. Then, lower the rare earth alloy modifier seed crystal for preheating for 50 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 10 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 8 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 150 mm. The drawing speed is then increased to 8.1 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Towards the end of the crystal growth stage, the drawing speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0080] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 4 mm, a blasting speed of 120 m / s, a blasting angle of 90°, and a shot peening coverage of 180%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 2 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 300℃ for 80 min, followed by water quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 1000 μm, the thickness of the fine-grained region was 2 mm, the width of the internal longitudinal columnar crystals was 2 mm, and the proportion of small-angle grain boundaries was 30%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 70 ppm, and the oxygen content internally was 50 ppm.

[0081] Example 19 A method for preparing an antioxidant La-Mg alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: lanthanum and magnesium were 5 wt.% and 95 wt.%, respectively, with the lanthanum having a purity of 99.9% and the magnesium having a purity of 99.5%. The lanthanum and magnesium were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.01 MPa, and the furnace was cleaned twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.01 MPa argon gas. The power was then slowly increased until the magnesium and lanthanum blocks were completely melted, maintaining a superheat of 5°C on the solution surface. The rare earth alloy modifier seed crystal was then lowered for preheating for 30 minutes before being introduced into the melt for welding. The seed crystal was then rapidly raised at a speed of 3 mm / min to create a 20 mm long, 3 mm diameter neck. After necking, the pulling speed was reduced to 0.2 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 500 mm. Then, the pulling speed was increased to 0.4 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare-earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 1 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare-earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0082] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.1 mm, a blasting speed of 40 m / s, a blasting angle of 60°, and a shot peening coverage of 100%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.1 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 300℃ for 15 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 130 nm, the thickness of the fine-grained region was 0.1 mm, the width of the internal longitudinal columnar crystals was 20 mm, and the proportion of small-angle grain boundaries was 90%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 45 ppm, and the oxygen content internally was 20 ppm.

[0083] Example 20 A method for preparing an antioxidant Ce-Mg alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their weight percentages: cerium and magnesium were 10 wt.% and 90 wt.%, respectively, with the cerium having a purity of 99.9% and the magnesium having a purity of 99.5%. The cerium and magnesium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was cleaned twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.02 MPa argon gas. The power was then slowly increased until the magnesium and cerium blocks were completely melted, maintaining a superheat of 10°C on the solution surface. The rare earth alloy modifier seed crystal was then lowered for preheating for 40 minutes before being introduced into the melt for welding. The seed crystal was then rapidly raised at a speed of 4 mm / min to create a 20 mm long, 4 mm diameter neck. After necking, the pulling speed was reduced to 1 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 450 mm. Then, the pulling speed was increased to 1.2 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 6 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0084] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.5 mm, a blasting speed of 60 m / s, a blasting angle of 70°, and a shot peening coverage of 120%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.5 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 400℃ for 30 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 100 μm, the thickness of the fine-grained region was 0.5 mm, the width of the internal longitudinal columnar crystals was 15 mm, and the proportion of small-angle grain boundaries was 70%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 50 ppm, and the oxygen content internally was 30 ppm.

[0085] Example 21 A method for preparing an antioxidant Gd-Mg alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: gadolinium and magnesium are 15 wt.% and 85 wt.%, respectively, with the gadolinium having a purity of 99.9% and the magnesium having a purity of 99.5%. Place the gadolinium and magnesium raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.04 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 5 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the magnesium and gadolinium blocks are completely melted, maintaining a superheat of 20°C on the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 50 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 5 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 400 mm. The pulling speed is then increased to 2.3 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the pulling speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0086] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 1 mm, a blasting speed of 80 m / s, a blasting angle of 80°, and a shot peening coverage of 130%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 1 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a nitrogen-protected heat treatment furnace at a recrystallization temperature of 350°C for 45 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 150 μm, the thickness of the fine-grained region was 1 mm, the width of the internal longitudinal columnar crystals was 13 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 54 ppm, and the oxygen content internally was 32 ppm.

[0087] Example 22 A method for preparing an antioxidant Y-Mg alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: yttrium and magnesium are 20 wt.% and 80 wt.%, respectively, with the yttrium having a purity of 99.9% and the magnesium having a purity of 99.5%. Place the yttrium and magnesium raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.03 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 5 minutes, introduce 0.03 MPa argon gas, then slowly increase the power until the magnesium and yttrium blocks are completely melted, maintaining a superheat of 30°C at the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 60 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 3 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 25 mm. The pulling speed is then increased to 3.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the pulling speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0088] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 2 mm, a blasting speed of 90 m / s, a blasting angle of 90°, and a shot peening coverage of 150%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.5 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 600℃ for 60 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 200 μm, the thickness of the fine-grained region was 1.5 mm, the width of the internal longitudinal columnar crystals was 10 mm, and the proportion of small-angle grain boundaries was 63%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 57 ppm, and the oxygen content internally was 35 ppm.

[0089] Example 23 A method for preparing an antioxidant Sc-Mg alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: scandium metal 25 wt.% and magnesium metal 75 wt.%, with the scandium metal having a purity of 99.9% and the magnesium metal having a purity of 99.5%. Place the scandium metal and magnesium metal into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.04 MPa argon gas and repeat the furnace cleaning twice. After baking the furnace at low power for 10 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the magnesium and scandium blocks are completely melted, maintaining the solution surface temperature superheat at 40°C. Then, lower the rare earth alloy modifier seed crystal for preheating for 40 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 7 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 4 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 100 mm. The drawing speed is then increased to 4.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Towards the end of the crystal growth stage, the drawing speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0090] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 3 mm, a blasting speed of 100 m / s, a blasting angle of 90°, and a shot peening coverage of 170%. This resulted in rare earth alloy modifier rods with plastic deformation within a 2 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 450℃ for 70 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 400 μm, the thickness of the fine-grained region was 2 mm, the width of the internal longitudinal columnar crystals was 8 mm, and the proportion of small-angle grain boundaries was 60%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 63 ppm, and the oxygen content internally was 40 ppm.

[0091] Example 24 A method for preparing an antioxidant Er-Mg alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: erbium metal 30 wt.% and magnesium metal 70 wt.%, with erbium metal purity of 99.9% and magnesium metal purity of 99.5%. Place the erbium metal and magnesium metal into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.04 MPa argon gas and repeat the furnace cleaning twice. After baking the furnace at low power for 10 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the magnesium and erbium blocks in the furnace are completely melted, maintaining the superheat of the solution surface at 50°C. Then, lower the rare earth alloy modifier seed crystal for preheating for 50 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 10 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 8 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 150 mm. The drawing speed is then increased to 8.1 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Towards the end of the crystal growth stage, the drawing speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0092] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 4 mm, a blasting speed of 120 m / s, a blasting angle of 90°, and a shot peening coverage of 180%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 2 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 300℃ for 80 min, followed by water quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 1000 μm, the thickness of the fine-grained region was 2 mm, the width of the internal longitudinal columnar crystals was 2 mm, and the proportion of small-angle grain boundaries was 30%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 70 ppm, and the oxygen content internally was 50 ppm.

[0093] Example 25 A method for preparing an antioxidant La-Ti alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: lanthanum and titanium were 5 wt.% and 95 wt.%, respectively, with the lanthanum having a purity of 99.9% and the titanium having a purity of 99.5%. The lanthanum and titanium were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.01 MPa, and the furnace was cleaned twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.01 MPa argon gas. The power was then slowly increased until the titanium and lanthanum blocks were completely melted, maintaining a superheat of 5°C on the solution surface. The rare earth alloy modifier seed crystal was then lowered for preheating for 30 minutes before being introduced into the melt for welding. The seed crystal was then rapidly raised at 3 mm / min to create a 20 mm long, 3 mm diameter neck. After necking, the pulling speed was reduced to 0.2 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 480 mm. Then, the pulling speed was increased to 0.4 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare-earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 1 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare-earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0094] Rare earth alloy modifier rods with columnar crystal structure both inside and out, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.1 mm, a blasting speed of 40 m / s, a blasting angle of 60°, and a shot peening coverage of 100%. This resulted in rare earth alloy modifier rods with plastic deformation within a 0.2 mm surface layer while maintaining columnar crystal structure internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 300℃ for 15 min, followed by oil quenching. Analysis showed that the average grain size of the rare earth alloy modifier rod surface was 135 nm, the thickness of the fine-grained region was 0.2 mm, the width of the internal longitudinal columnar crystals was 20 mm, and the proportion of small-angle grain boundaries was 90%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 45 ppm, and the oxygen content inside was 20 ppm.

[0095] Example 26 A method for preparing an antioxidant Ce-Ti alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their weight percentages: cerium and titanium were 10 wt.% and 90 wt.%, respectively, with the purity of cerium being 99.9% and the purity of titanium being 99.5%. The cerium and titanium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was cleaned twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.02 MPa argon gas. The power was then slowly increased until the titanium and cerium blocks were completely melted, maintaining a superheat of 10°C on the solution surface. The rare earth alloy modifier seed crystal was then lowered for preheating for 40 minutes before being introduced into the melt for welding. The seed crystal was then rapidly raised at a speed of 4 mm / min to create a 20 mm long, 4 mm diameter neck. After necking, the pulling speed was reduced to 1 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 430 mm. Then, the pulling speed was increased to 1.2 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 6 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0096] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.5 mm, a blasting speed of 60 m / s, a blasting angle of 70°, and a shot peening coverage of 120%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.6 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 400℃ for 30 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 130 μm, the thickness of the fine-grained region was 0.6 mm, the width of the internal longitudinal columnar crystals was 15 mm, and the proportion of small-angle grain boundaries was 70%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 50 ppm, and the oxygen content internally was 30 ppm.

[0097] Example 27 A method for preparing an antioxidant Gd-Ti alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: gadolinium metal 15 wt.% and titanium metal 85 wt.%, with gadolinium metal having a purity of 99.9% and titanium metal having a purity of 99.5%. Place the gadolinium metal and titanium metal into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.04 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 5 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the titanium and gadolinium blocks are completely melted, maintaining a superheat of 20°C at the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 50 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 5 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 380 mm. The pulling speed is then increased to 2.3 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the pulling speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0098] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 1 mm, a blasting speed of 80 m / s, a blasting angle of 80°, and a shot peening coverage of 130%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 1.2 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a nitrogen-protected heat treatment furnace at a recrystallization temperature of 350°C for 45 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 170 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 13 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 54 ppm, and the oxygen content internally was 32 ppm.

[0099] Example 28 A method for preparing an antioxidant Y-Ti alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: yttrium and titanium are 20 wt.% and 80 wt.%, respectively, with the yttrium having a purity of 99.9% and the titanium having a purity of 99.5%. Place the yttrium and titanium raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.03 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 5 minutes, introduce 0.03 MPa argon gas, then slowly increase the power until the titanium and yttrium blocks are completely melted, maintaining a superheat of 30°C at the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 60 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 3 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 15 mm. The drawing speed is then increased to 3.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0100] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 2 mm, a blasting speed of 90 m / s, a blasting angle of 90°, and a shot peening coverage of 150%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 1.5 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 500℃ for 120 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 800 μm, the thickness of the fine-grained region was 1.5 mm, the width of the internal longitudinal columnar crystals was 10 mm, and the proportion of small-angle grain boundaries was 63%. After being placed under ambient atmospheric conditions for 15 days, the oxygen content on the surface of the rods was 57 ppm, and the oxygen content internally was 35 ppm.

[0101] Example 29 A method for preparing an antioxidant Sc-Ti alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: scandium metal 25 wt.% and titanium metal 75 wt.%, with the scandium metal having a purity of 99.9% and the titanium metal having a purity of 99.5%. The scandium metal and titanium metal were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.04 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 10 minutes, followed by the introduction of 0.04 MPa argon gas. The power was then slowly increased until the titanium and scandium blocks were completely melted, maintaining a superheat of 40°C at the solution surface. A rare earth alloy modifier seed crystal was then lowered for preheating for 40 minutes before being introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 7 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 4 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 155 mm. The drawing speed is then increased to 4.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Towards the end of the crystal growth stage, the drawing speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0102] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 3 mm, a blasting speed of 100 m / s, a blasting angle of 90°, and a shot peening coverage of 170%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.8 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 450°C for 70 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 600 μm, the thickness of the fine-grained region was 1.8 mm, the width of the internal longitudinal columnar crystals was 8 mm, and the proportion of small-angle grain boundaries was 60%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 63 ppm, and the oxygen content internally was 40 ppm.

[0103] Example 30 A method for preparing an antioxidant Er-Ti alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their weight percentages: 45 wt.% erbium and 55 wt.% titanium, with the erbium having a purity of 99.9% and the titanium having a purity of 99.5%. The erbium and titanium were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, 0.04 MPa argon gas was introduced, and the furnace was cleaned twice. The furnace was then preheated at low power for 10 minutes, followed by the introduction of 0.04 MPa argon gas. The power was then slowly increased until the titanium and erbium blocks were completely melted, maintaining a superheat of 50°C at the solution surface. A rare earth alloy modifier seed crystal was then lowered for preheating for 50 minutes before being introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 10 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 8 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 150 mm. The drawing speed is then increased to 8.1 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Towards the end of the crystal growth stage, the drawing speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0104] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 4 mm, a blasting speed of 120 m / s, a blasting angle of 90°, and a shot peening coverage of 180%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.6 mm layer on the surface, while the internal structure remained columnar. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 300℃ for 100 min, followed by water quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 900 μm, the thickness of the fine-grained region was 0.6 mm, the width of the internal longitudinal columnar crystals was 2 mm, and the proportion of small-angle grain boundaries was 15%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 70 ppm, and the oxygen content inside was 50 ppm.

[0105] Example 31 A method for preparing an antioxidant La-Ni alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: lanthanum and nickel were 5 wt.% and 95 wt.%, respectively, with the lanthanum having a purity of 99.9% and the nickel having a purity of 99.5%. The lanthanum and nickel were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.01 MPa, and the furnace was cleaned twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.01 MPa argon gas. The power was then slowly increased until the nickel and lanthanum blocks were completely melted, maintaining a surface superheat of 5°C. The rare earth alloy modifier seed crystal was then lowered for preheating for 30 minutes before being introduced into the melt for welding. The seed crystal was then rapidly raised at 3 mm / min to create a 20 mm long, 3 mm diameter neck. After necking, the pulling speed was reduced to 0.2 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 480 mm. Then, the pulling speed was increased to 0.4 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare-earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 1 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare-earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0106] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.1 mm, a blasting speed of 40 m / s, a blasting angle of 60°, and a shot peening coverage of 100%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.2 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 800℃ for 15 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 135 nm, the thickness of the fine-grained region was 0.2 mm, the width of the internal longitudinal columnar crystals was 20 mm, and the proportion of small-angle grain boundaries was 90%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 45 ppm, and the oxygen content internally was 20 ppm.

[0107] Example 32 A method for preparing an antioxidant Ce-Ni alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: cerium and nickel are 10 wt.% and 90 wt.%, respectively, with the purity of cerium being 99.9% and the purity of nickel being 99.5%. Place the cerium and nickel raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.02 MPa argon gas and repeat the furnace cleaning twice. After baking the furnace at low power for 5 minutes, introduce 0.02 MPa argon gas, then slowly increase the power until the nickel and cerium blocks are completely melted, maintaining a superheat of 10°C on the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 40 minutes, and then introduce the seed crystal into the melt for welding. Next, rapidly raise the seed crystal at a speed of 4 mm / min to draw out a 20 mm long, 4 mm diameter neck. After necking, reduce the drawing speed to 1 mm / min, gradually increasing the diameter of the rare earth alloy modifier crystal to 430 mm. Then, the pulling speed was increased to 1.2 mm / min to stop the crystal diameter from growing, and the crystal entered a stable, constant-diameter growth stage. The pulling speed and temperature were continuously adjusted using a PID program to keep the crystal diameter fluctuations of the rare earth alloy modifier within a certain error range. Towards the end of the crystal growth stage, the pulling speed was increased to 6 mm / min to slowly reduce the crystal diameter until all the melt in the crucible was pulled out, resulting in a rare earth alloy modifier ingot with columnar crystals on both the surface and inside.

[0108] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 0.5 mm, a blasting speed of 60 m / s, a blasting angle of 70°, and a shot peening coverage of 120%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 0.6 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 900℃ for 30 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 165 μm, the thickness of the fine-grained region was 0.6 mm, the width of the internal longitudinal columnar crystals was 15 mm, and the proportion of small-angle grain boundaries was 70%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 50 ppm, and the oxygen content internally was 30 ppm.

[0109] Example 33 A method for preparing an antioxidant Gd-Ni alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: gadolinium and nickel are 15 wt.% and 85 wt.%, respectively, with the gadolinium having a purity of 99.9% and the nickel having a purity of 99.5%. Place the gadolinium and nickel raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.04 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 5 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the nickel and gadolinium blocks are completely melted, maintaining a superheat of 20°C on the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 50 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 5 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 330 mm. The drawing speed is then increased to 2.3 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0110] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 1 mm, a blasting speed of 80 m / s, a blasting angle of 80°, and a shot peening coverage of 130%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.2 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a nitrogen-protected heat treatment furnace at a recrystallization temperature of 1000℃ for 45 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 600 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 13 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 54 ppm, and the oxygen content internally was 32 ppm.

[0111] Example 34 A method for preparing an antioxidant Y-Ni alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: yttrium and nickel are 20 wt.% and 80 wt.%, respectively, with the yttrium having a purity of 99.9% and the nickel having a purity of 99.5%. Place the yttrium and nickel raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.03 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 5 minutes, introduce 0.03 MPa argon gas, then slowly increase the power until the nickel and yttrium blocks are completely melted, maintaining a superheat of 30°C at the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 60 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a 20 mm long, 5 mm diameter neck. After necking, the pulling speed is reduced to 3 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 75 mm. The pulling speed is then increased to 3.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust the temperature, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the pulling speed is increased to 8 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0112] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 2 mm, a blasting speed of 90 m / s, a blasting angle of 90°, and a shot peening coverage of 150%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.5 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 1100℃ for 120 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 800 μm, the thickness of the fine-grained region was 1.5 mm, the width of the internal longitudinal columnar crystals was 10 mm, and the proportion of small-angle grain boundaries was 63%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 57 ppm, and the oxygen content internally was 35 ppm.

[0113] Example 35 A method for preparing an antioxidant Sc-Ni alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: scandium metal 25 wt.% and nickel metal 75 wt.%, with scandium metal purity of 99.9% and nickel metal raw material purity of 99.5%. Place the scandium metal and nickel metal raw material into the induction melting crucible of the crystal growth furnace. After evacuating the furnace to a vacuum level below 0.6 Pa, introduce 0.04 MPa argon gas and repeat the furnace cleaning twice. After baking the furnace at low power for 10 minutes, introduce 0.04 MPa argon gas, and then slowly increase the power until the nickel and scandium blocks in the furnace are completely melted, maintaining the superheat of the solution surface at 40°C. Then, lower the rare earth alloy modifier seed crystal for preheating for 40 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 7 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 4 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 35 mm. The pulling speed is then increased to 4.5 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the pulling speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0114] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast steel shot with a diameter of 3 mm, a blasting speed of 100 m / s, a blasting angle of 90°, and a shot peening coverage of 170%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.8 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 1200℃ for 70 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 950 μm, the thickness of the fine-grained region was 1.8 mm, the width of the internal longitudinal columnar crystals was 8 mm, and the proportion of small-angle grain boundaries was 60%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 63 ppm, and the oxygen content internally was 40 ppm.

[0115] Example 36 A method for preparing an antioxidant Er-Ni alloy modifier according to the present invention includes the following steps: Prepare the alloy according to the following weight percentages: 45 wt.% erbium and 55 wt.% nickel, with erbium purity of 99.9% and nickel purity of 99.5%. Place the erbium and nickel raw materials into the induction melting crucible of the crystal growth furnace. Evacuate the furnace to below 0.6 Pa, then introduce 0.04 MPa argon gas and repeat the furnace cleaning process twice. After baking the furnace at low power for 10 minutes, introduce 0.04 MPa argon gas, then slowly increase the power until the nickel and erbium blocks are completely melted, maintaining a superheat of 50°C on the solution surface. Then, lower the rare earth alloy modifier seed crystal for preheating for 50 minutes, and then introduce the seed crystal into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 10 mm / min to draw out a thin neck with a length of 20 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 8 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 10 mm. The drawing speed is then increased to 8.1 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust these parameters, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 9 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0116] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was cast iron shot with a diameter of 4 mm, a blasting speed of 120 m / s, a blasting angle of 90°, and a shot peening coverage of 180%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 0.6 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in a helium-protected heat treatment furnace at a recrystallization temperature of 1200℃ for 120 min, followed by water quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 1000 μm, the thickness of the fine-grained region was 0.6 mm, the width of the internal longitudinal columnar crystals was 2 mm, and the proportion of small-angle grain boundaries was 15%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 70 ppm, and the oxygen content internally was 50 ppm.

[0117] Example 37 A method for preparing an antioxidant Ce-Fe-Cr alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: cerium, iron, and chromium were 30 wt.%, 69.95 wt.%, and 0.05 wt.%, respectively, with the purity of cerium being 99.9% and the purity of iron and chromium being 99.5%. The rare earth cerium, iron, and chromium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of argon gas at 0.03 MPa. The power was then slowly increased until the iron, cerium, and chromium blocks were completely melted, maintaining a superheat of 10°C at the solution surface. A rare earth alloy modifier seed crystal was then lowered for preheating for 40 minutes before being introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 10 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 0.8 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 350 mm. The pulling speed is then increased to 1 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust the temperature, keeping the rare earth alloy modifier crystal diameter fluctuations within a certain error range. At the end of the crystal growth stage, the pulling speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn out, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and inside.

[0118] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic pellets with a diameter of 1 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 100%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.7 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 500℃ for 30 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 50 μm, the thickness of the fine-grained region was 1.7 mm, the width of the internal longitudinal columnar crystals was 6 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 55 ppm, and the oxygen content internally was 30 ppm.

[0119] Example 38 A method for preparing an antioxidant Ce-Fe-Nb alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their weight percentages: cerium, iron, and niobium were 35 wt.%, 60 wt.%, and 5 wt.%, respectively, with the purity of cerium being 99.9% and the purity of iron and niobium being 99.5%. The rare earth cerium, iron, and niobium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of argon gas at 0.03 MPa. The power was then slowly increased until the iron, cerium, and niobium blocks were completely melted, maintaining a superheat of 20°C at the solution surface. A rare earth alloy modifier seed crystal was then lowered for preheating for 40 minutes before being introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 10 mm and a diameter of 5 mm. After necking, the pulling speed is reduced to 0.8 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 270 mm. The pulling speed is then increased to 1 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Towards the end of the crystal growth stage, the pulling speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0120] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic pellets with a diameter of 4 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 200%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.7 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 400℃ for 120 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 600 μm, the thickness of the fine-grained region was 1.7 mm, the width of the internal longitudinal columnar crystals was 6 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 65 ppm, and the oxygen content internally was 49 ppm.

[0121] Example 39 A method for preparing an antioxidant Ce-Fe-Nb alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: cerium, iron, and niobium were 20 wt.%, 70 wt.%, and 10 wt.%, respectively, with the purity of cerium being 99.9% and the purity of iron and niobium being 99.5%. The rare earth cerium, iron, and niobium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of argon gas at 0.03 MPa. The power was then slowly increased until the iron, cerium, and niobium blocks were completely melted, maintaining a superheat of 20°C at the solution surface. A rare earth alloy modifier seed crystal was then lowered for preheating for 40 minutes before being introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 10 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 200 mm. The drawing speed is then increased to 2.4 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0122] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 3 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 200%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 1.2 mm layer on the surface, while the internal structure remained columnar. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace, recrystallized at 450°C for 15 min, and subsequently quenched in oil. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 10 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 4 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 55 ppm, and the oxygen content inside was 40 ppm.

[0123] Example 40 A method for preparing an antioxidant Ce-Fe-Nb alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: cerium, iron, and niobium were 20 wt.%, 65 wt.%, and 15 wt.%, respectively, with the purity of cerium being 99.9% and the purity of iron and niobium being 99.5%. The rare earth cerium, iron, and niobium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of argon gas at 0.03 MPa. The power was then slowly increased until the iron, cerium, and niobium blocks were completely melted, maintaining a superheat of 20°C at the solution surface. A rare earth alloy modifier seed crystal was then lowered for preheating for 40 minutes before being introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 10 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 200 mm. The drawing speed is then increased to 2.4 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0124] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 3 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 200%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.2 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 450℃ for 15 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 20 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 4 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 50 ppm, and the oxygen content internally was 38 ppm.

[0125] Example 41 A method for preparing an antioxidant Ce-Fe-Nb alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their weight percentages: cerium, iron, and niobium were 34 wt.%, 65 wt.%, and 1 wt.%, respectively, with the purity of cerium being 99.9% and the purity of iron and niobium being 99.5%. The rare earth cerium, iron, and niobium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of argon gas at 0.03 MPa. The power was then slowly increased until the iron, cerium, and niobium blocks were completely melted, maintaining a superheat of 20°C at the solution surface. A rare earth alloy modifier seed crystal was then lowered for preheating for 40 minutes before being introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 10 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 200 mm. The drawing speed is then increased to 2.4 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0126] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 3 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 200%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 1.2 mm layer on the surface, while the internal structure remained columnar. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 450℃ for 15 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 80 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 4 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 65 ppm, and the oxygen content inside was 55 ppm.

[0127] Example 42 A method for preparing an antioxidant Ce-Fe-V alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their weight percentages: cerium, iron, and vanadium were 34 wt.%, 65 wt.%, and 1 wt.%, respectively, with the purity of cerium being 99.9% and the purity of iron and vanadium being 99.5%. The cerium, iron, and vanadium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of argon gas at 0.03 MPa. The power was then slowly increased until the iron, cerium, and vanadium blocks were completely melted, maintaining a superheat of 20°C at the solution surface. A rare earth alloy modifier seed crystal was then lowered for preheating for 40 minutes before being introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 10 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 200 mm. The drawing speed is then increased to 2.4 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0128] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 3 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 200%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 1.2 mm layer on the surface, while the internal structure remained columnar. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace, recrystallized at 450°C for 15 min, and subsequently quenched in oil. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 50 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 4 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 60 ppm, and the oxygen content inside was 52 ppm.

[0129] Example 43 A method for preparing an antioxidant Ce-Fe-V-Nb alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: cerium, iron, vanadium, and niobium were 34 wt.%, 62 wt.%, 3 wt.%, and 1 wt.%, respectively, with the purity of cerium being 99.9% and the purity of the iron, vanadium, and niobium raw materials being 99.5%. The rare earth cerium, iron, vanadium, and niobium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to a vacuum level below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of argon gas at 0.03 MPa. The power was then slowly increased until the iron, cerium, vanadium, and niobium blocks were completely melted, maintaining a superheat of 20°C at the solution surface. Afterward, a rare earth alloy modifier seed crystal was lowered for preheating for 40 minutes, and then the seed crystal was introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 10 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 200 mm. The drawing speed is then increased to 2.4 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0130] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 3 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 200%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 1.2 mm layer on the surface, while the internal structure remained columnar. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace, recrystallized at 450°C for 15 min, and subsequently quenched in oil. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 55 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 4 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 55 ppm, and the oxygen content inside was 45 ppm.

[0131] Example 44 A method for preparing an antioxidant Ce-Fe-Cr-V-Nb alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their weight percentages: cerium, iron, chromium, vanadium, and niobium were 34 wt.%, 60 wt.%, 2 wt.%, 3 wt.%, and 1 wt.%, respectively. The purity of the rare earth cerium was 99.9%, and the purity of the iron, chromium, vanadium, and niobium raw materials was 99.5%. The rare earth cerium, iron, chromium, vanadium, and niobium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.03 MPa argon gas. The power was then slowly increased until the iron, cerium, chromium, vanadium, and niobium blocks were completely melted, maintaining a superheat of 20°C on the solution surface. Afterward, a rare earth alloy modifier seed crystal was lowered for preheating for 40 minutes, and then the seed crystal was introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 10 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 200 mm. The drawing speed is then increased to 2.4 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0132] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 3 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 200%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 1.2 mm layer on the surface, while the internal structure remained columnar. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 450°C for 15 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 60 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 4 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 53 ppm, and the oxygen content inside was 42 ppm.

[0133] Example 45 A method for preparing an antioxidant Ce-Fe-Al-Nb alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their weight percentages: cerium, iron, aluminum, and niobium were 34 wt.%, 62 wt.%, 3 wt.%, and 1 wt.%, respectively, with the purity of cerium being 99.9% and the purity of iron, aluminum, and niobium being 99.5%. The rare earth cerium, iron, aluminum, and niobium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of argon gas at 0.03 MPa. The power was then slowly increased until the iron, cerium, aluminum, and niobium blocks were completely melted, maintaining a superheat of 20°C at the solution surface. A rare earth alloy modifier seed crystal was then lowered for preheating for 40 minutes before being introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 10 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 200 mm. The drawing speed is then increased to 2.4 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0134] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 3 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 200%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 1.2 mm layer on the surface, while the internal structure remained columnar. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace, recrystallized at 450°C for 15 min, and subsequently quenched in oil. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 40 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 4 mm, and the proportion of small-angle grain boundaries was 65%. After being placed under ambient atmospheric conditions for 15 days, the oxygen content on the surface of the rods was 49 ppm, and the oxygen content inside was 40 ppm.

[0135] Example 46 A method for preparing an antioxidant Ce-Fe-Al-Ti-Nb alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: cerium, iron, aluminum, titanium, and niobium were 34 wt.%, 55 wt.%, 7 wt.%, 3 wt.%, and 1 wt.%, respectively. The purity of the rare earth cerium was 99.9%, and the purity of the iron, aluminum, titanium, and niobium raw materials was 99.5%. The rare earth cerium, iron, aluminum, titanium, and niobium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was rinsed twice. The furnace was then preheated at low power for 5 minutes, followed by the introduction of 0.03 MPa argon gas. The power was then slowly increased until the iron, cerium, aluminum, titanium, and niobium blocks were completely melted, maintaining a superheat of 20°C at the solution surface. Afterward, a rare earth alloy modifier seed crystal was lowered for preheating for 40 minutes, and then the seed crystal was introduced into the melt for welding. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to draw out a thin neck with a length of 10 mm and a diameter of 5 mm. After necking, the drawing speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 200 mm. The drawing speed is then increased to 2.4 mm / min, stopping the crystal diameter growth and allowing the crystal to enter a stable, constant-diameter growth stage. PID control of the drawing speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. At the end of the crystal growth stage, the drawing speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0136] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic shot with a diameter of 3 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 200%. This resulted in rare earth alloy modifier rods with plastic deformation occurring within a 1.2 mm surface layer while maintaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 450°C for 15 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 30 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 4 mm, and the proportion of small-angle grain boundaries was 65%. After being placed under ambient atmospheric conditions for 15 days, the oxygen content on the surface of the rods was 40 ppm, and the oxygen content internally was 33 ppm.

[0137] Example 47 A method for preparing an antioxidant Ce-Fe-Al-Ti-Cr-Nb alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: cerium, iron, aluminum, titanium, chromium, and niobium were 34 wt.%, 50 wt.%, 7 wt.%, 3 wt.%, 5 wt.%, and 1 wt.%, respectively. The purity of the rare earth cerium was 99.9%, and the purity of the iron, aluminum, titanium, chromium, and niobium raw materials was 99.5%. The rare earth cerium, iron, aluminum, titanium, chromium, and niobium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was cleaned twice. After baking the furnace at low power for 5 minutes, argon gas was introduced at 0.03 MPa. The power was then slowly increased until the iron, cerium, aluminum, titanium, chromium, and niobium blocks inside the furnace were completely melted, maintaining a superheat of 20°C at the solution surface. Afterward, the rare earth alloy modifier seed crystal is lowered and preheated for 40 minutes before being fused into the melt. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to create a 10 mm long, 5 mm diameter neck. After necking, the pulling speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 200 mm. The pulling speed is then increased to 2.4 mm / min, stopping the crystal diameter growth and entering a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Toward the end of the crystal growth stage, the pulling speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0138] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic pellets with a diameter of 3 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 200%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.2 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 450°C for 15 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 25 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 4 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 40 ppm, and the oxygen content internally was 30 ppm.

[0139] Example 48 A method for preparing an antioxidant La-Cu-Al-Ti-Cr-Nb alloy modifier according to the present invention includes the following steps: The alloy components were prepared according to their respective weight percentages: lanthanum, copper, aluminum, titanium, chromium, and niobium were 34 wt.%, 50 wt.%, 7 wt.%, 3 wt.%, 5 wt.%, and 1 wt.%, respectively. The purity of the rare earth lanthanum was 99.9%, and the purity of the copper, aluminum, titanium, chromium, and niobium raw materials was 99.5%. The rare earth lanthanum, copper, aluminum, titanium, chromium, and niobium raw materials were placed in the induction melting crucible of the crystal growth furnace. After evacuating the furnace to below 0.6 Pa, argon gas was introduced at 0.02 MPa, and the furnace was cleaned twice. After baking the furnace at low power for 5 minutes, argon gas was introduced at 0.03 MPa. The power was then slowly increased until the copper, lanthanum, aluminum, titanium, chromium, and niobium blocks in the furnace were completely melted, maintaining a superheat of 20°C at the solution surface. Afterward, the rare earth alloy modifier seed crystal is lowered and preheated for 40 minutes before being fused into the melt. Then, the seed crystal is rapidly raised at a speed of 6 mm / min to create a 10 mm long, 5 mm diameter neck. After necking, the pulling speed is reduced to 2 mm / min, allowing the rare earth alloy modifier crystal diameter to gradually increase to 200 mm. The pulling speed is then increased to 2.4 mm / min, stopping the crystal diameter growth and entering a stable, constant-diameter growth stage. PID control of the pulling speed and temperature is used to continuously adjust the crystal diameter, keeping fluctuations within a certain error range. Toward the end of the crystal growth stage, the pulling speed is increased to 5 mm / min, slowly reducing the crystal diameter until all the melt in the crucible is drawn, resulting in a rare earth alloy modifier crystal rod with columnar crystals on both the surface and interior.

[0140] Rare earth alloy modifier rods with columnar crystal structures both internally and externally, obtained by the above-mentioned crystal growth method, were placed in a shot peening device. The shot peening material was ceramic pellets with a diameter of 3 mm, a blasting speed of 120 m / s, a blasting angle of 60°, and a shot peening coverage of 200%. This resulted in rare earth alloy modifier rods exhibiting plastic deformation within a 1.2 mm surface layer while retaining columnar crystal structures internally. The shot-peened rare earth alloy modifier rods were then placed in an argon-protected heat treatment furnace at a recrystallization temperature of 450°C for 15 min, followed by oil quenching. Analysis showed that the average grain size on the surface of the rare earth alloy modifier rods was 20 μm, the thickness of the fine-grained region was 1.2 mm, the width of the internal longitudinal columnar crystals was 4 mm, and the proportion of small-angle grain boundaries was 65%. After being placed in a normal atmospheric environment for 15 days, the oxygen content on the surface of the rods was 42 ppm, and the oxygen content internally was 30 ppm.

[0141] Comparative Example 1 Comparative Example 1 is a commercially available lanthanum-iron alloy (La: 5wt%, Fe: 95wt%). The surface crystal diameter is 1000μm, the fine grain thickness is 0.2mm, the internal crystal structure is columnar crystals pointing towards the center, the columnar crystal width is 30mm, and there are no small-angle grain boundaries. After being placed at room temperature for 15 days, the surface oxygen content is 200ppm and the internal oxygen content is 180ppm.

[0142] Comparative Example 2 Comparative Example 2 is a commercially available cerium-iron-chromium alloy (Ce: 30wt%, Fe: 69.95wt%, Cr 0.05wt.%). The surface crystal diameter is 1500μm, the fine grain thickness is 0.5mm, the internal crystal structure is columnar crystals pointing towards the center, the columnar crystal width is 20mm, and there are no small-angle grain boundaries. After being placed at room temperature for 15 days, the surface oxygen content is 160ppm and the internal oxygen content is 150ppm.

[0143] Comparative Example 3 Comparative Example 3 is a commercially available yttrium-iron alloy (Y: 20wt%, Fe: 80wt%). The surface crystal diameter is 2000μm, the fine grain thickness is 0.3mm, the internal crystal structure is columnar crystals pointing towards the center, the columnar crystal width is 16mm, and there are no small-angle grain boundaries. After being placed at room temperature for 15 days, the surface oxygen content is 250ppm and the internal oxygen content is 190ppm.

[0144] Comparative Example 4 Comparative Example 4 is a commercially available cerium-iron-niobium alloy (Ce: 35wt%, Fe: 60wt%, Nb: 5wt.%). The surface crystal diameter is 2300μm, the fine grain thickness is 0.3mm, the internal crystal structure is columnar crystals pointing towards the center, the columnar crystal width is 18mm, and there are no small-angle grain boundaries. After being placed at room temperature for 15 days, the surface oxygen content is 164ppm and the internal oxygen content is 130ppm.

[0145] Comparative Example 5 Comparative Example 5 is a commercially available cerium-iron-niobium alloy (Ce: 20wt%, Fe: 65wt%, Nb: 15wt.%). The surface crystal diameter is 1600μm, the fine grain thickness is 0.8mm, the internal crystal structure is columnar crystals pointing towards the center, the columnar crystal width is 15mm, there are no small-angle grain boundaries, and after being placed at room temperature for 15 days, the surface oxygen content is 150ppm and the internal oxygen content is 100ppm.

[0146] Comparative Example 6 Comparative Example 6 is a commercially available cerium-iron-niobium alloy (Ce: 34wt%, Fe: 65wt%, Nb: 1wt.%). The surface crystal diameter is 3400μm, the fine grain thickness is 0.5mm, the internal crystal structure is columnar crystals pointing towards the center, the columnar crystal width is 30mm, and there are no small-angle grain boundaries. After being placed at room temperature for 15 days, the surface oxygen content is 150ppm and the internal oxygen content is 100ppm.

[0147] Table 1 compares the crystal structure and antioxidant properties of the above-mentioned embodiments of the present invention and commercially available comparative rare earth alloy modifiers, as shown below.

[0148] Table 1 To further verify the beneficial effects of the antioxidant rare earth alloy modifier material, a comparative experiment on the addition of rare earth alloy modifier was conducted in ferroalloys.

[0149] Comparative Experiment 1 Rare earth steel was smelted in 3-ton ladles using both Example 1 and Comparative Example 1, with a theoretical rare earth addition of 200 ppm. The rare earth content, average inclusion size, rare earth yield, and number of consecutive castings for each rare earth steel sample are shown in Table 2. It can be observed that after adding the antioxidant lanthanum-iron alloy modifier of Example 1, the rare earth content, average inclusion size, and number of consecutive castings in the steel are significantly better than those of the commercially available Comparative Example 1 modifier. This is because the rare earth alloy modifier material prepared in Example 1 has a fine-grained surface and columnar internal structure, which improves the intrinsic antioxidant properties of the modifier and effectively mitigates oxidation loss during storage, transportation, and application, thereby increasing the effective rare earth content and utilization rate in the rare earth alloy modifier. On the one hand, it leverages the role of rare earth in modifying inclusions in steel to reduce the size of inclusions in the steel; on the other hand, it effectively reduces the introduction of foreign rare earth oxide inclusions during use, thereby ensuring the smooth operation of the continuous casting process at the application end, improving the stability of rare earth effects, and promoting a significant increase in rare earth yield.

[0150] Table 2 Comparative Experiment 2 Rare earth steel was smelted in 3-ton ladles using both Example 2 and Comparative Example 2, with a theoretical rare earth addition of 200 ppm. The rare earth content, average inclusion size, rare earth yield, and number of consecutive castings for each rare earth steel sample are shown in Table 3. It can be observed that the addition of the anti-oxidation cerium-iron-aluminum alloy modifier in Example 2 significantly improved the rare earth content, average inclusion size, and number of consecutive castings compared to the commercially available Comparative Example 2 modifier.

[0151] Table 3 Comparative Test 3 Rare earth steel was smelted in 3-ton ladles using both Example 3 and Comparative Example 3, with a theoretical rare earth addition of 200 ppm. The rare earth content, average inclusion size, rare earth yield, and number of consecutive castings for each rare earth steel sample are shown in Table 4. It can be observed that after adding the antioxidant yttrium iron alloy modifier in Example 3, the rare earth content, average inclusion size, and number of consecutive castings in the steel are significantly better than those of the commercially available Comparative Example 3 as a modifier.

[0152] Table 4 Comparative Test 4 Rare earth steel was smelted using the methods described in Example 4 and Comparative Example 4, respectively, in 3-ton ladles, with a theoretical rare earth addition of 200 ppm. The rare earth content, average inclusion size, rare earth yield, and number of consecutive castings for each rare earth steel sample are shown in Table 5. It can be observed that the addition of the antioxidant scandium-iron-copper alloy modifier in Example 4 significantly improved the rare earth content, average inclusion size, and number of consecutive castings compared to the commercially available Comparative Example 4 modifier.

[0153] Table 5 Comparative Test 5 Rare earth steel was smelted in 3-ton ladles using both Example 5 and Comparative Example 5, with a theoretical rare earth addition of 200 ppm. The rare earth content, average inclusion size, rare earth yield, and number of consecutive castings for each rare earth steel sample are shown in Table 6. It can be observed that the addition of the antioxidant scandium-iron-copper alloy modifier in Example 5 significantly improved the rare earth content, average inclusion size, and number of consecutive castings compared to the commercially available Comparative Example 5 modifier.

[0154] Table 6 Comparative Test 6 Rare earth steel was smelted using the methods described in Example 6 and Comparative Example 6, respectively, by adding rare earth elements to a 3-ton ladle. The theoretical addition amount of rare earth elements was 200 ppm. The rare earth content, average size of inclusions, rare earth yield, and number of consecutive castings for each rare earth steel sample are shown in Table 7. It can be found that after adding the antioxidant scandium-iron-copper alloy modifier in Example 6, the rare earth content, average size of inclusions, and number of consecutive castings in the steel were significantly better than those of the commercially available Comparative Example 6 as a modifier.

[0155] Table 7 The embodiments of this invention aim to protect an antioxidant rare earth alloy modifier and its preparation method, which has the following effects: 1. By constructing a composite crystal structure of fine surface grains and internal columnar grains, the intrinsic oxidation resistance of rare earth alloy modifiers is significantly improved by utilizing the high-density grain boundaries of the fine grain layer to block oxygen atoms and the longitudinally oriented grain boundaries of the columnar grain region to extend the oxygen diffusion path. This effectively solves the problem of protection failure caused by the peeling off of the protective layer in existing physical isolation methods, and greatly reduces the oxidation loss of materials during storage, transportation and use. 2. A process combination of crystal growth to prepare a columnar crystal structure, and surface shot peening to introduce a plastic deformation layer and recrystallization heat treatment to form a fine-grained surface layer, has been adopted to achieve precise control of the crystal structure of rare earth alloy modifiers. This avoids the cost increase caused by adding a large amount of precious alloying elements to improve oxidation resistance, and provides an economical and feasible technical path for the preparation of high-performance rare earth alloy modifiers. 3. By optimizing the internal grain boundary characteristics of rare earth alloy modifiers, the proportion of longitudinal grain boundaries reaches over 95% and the proportion of small-angle grain boundaries is controlled. While maintaining the excellent mechanical properties of the material, the rapid penetration of oxygen into the material interior along the transverse grain boundaries is effectively suppressed. This reduces the risk of introducing foreign oxide inclusions into the metal melt during the use of rare earth alloy modifiers, thereby ensuring the smoothness of the metal material preparation process and the uniformity of the final product's microstructure.

[0156] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An antioxidant rare earth alloy modifier, characterized in that, The surface of the rare earth alloy modifier is fine-grained, while its interior is columnar-shaped. The thickness of the fine-grained region on the surface is 0.1~2mm, and the grain size is 100nm~1000μm; The width of the internal columnar crystals is ≥1mm, and the area of ​​the columnar crystal region accounts for 90%~99.5%; The longitudinal grain boundaries inside the rare earth alloy modifier account for ≥95%, and the orientation deviation of the longitudinal grain boundaries is ≤25°, of which the proportion of small-angle grain boundaries below 15° is 10%~90%.

2. The antioxidant rare earth alloy modifier according to claim 1, characterized in that, The rare earth alloy modifier includes rare earth elements, a base metal, and additional elements. The rare earth elements include at least one of the following: lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, lutetium, scandium, and yttrium; The base metal includes at least one of iron, copper, aluminum, magnesium, titanium, and nickel; The additional elements include at least one of chromium, molybdenum, tungsten, cobalt, manganese, vanadium, niobium, zirconium, zinc, and tin.

3. The antioxidant rare earth alloy modifier according to claim 2, characterized in that, The content of the additional element in the rare earth alloy modifier is 0.05 wt.% to 15 wt.%.

4. The antioxidant rare earth alloy modifier according to claim 2, characterized in that, The rare earth components include at least one of lanthanum, cerium, gadolinium, yttrium, scandium, and erbium; The additional elements include at least one of chromium, vanadium, and niobium.

5. A method for preparing an antioxidant rare earth alloy modifier, characterized in that, The preparation of the rare earth alloy modifier as described in any one of claims 1-4 comprises the following steps: Rare earth alloy crystal rods with columnar crystals on both the surface and inside were prepared by crystal growth method; The rare earth alloy crystal rod is subjected to shot peening treatment to cause plastic deformation of the surface layer of the rare earth alloy crystal rod. The rare earth alloy crystal rods after shot peening are subjected to heat treatment in a protective atmosphere to cause recrystallization of the surface layer of the plastically deformed rare earth alloy crystal rods, forming a fine-grained layer while maintaining columnar crystals inside, thus obtaining an antioxidant rare earth alloy modifier.

6. The method for preparing the antioxidant rare earth alloy modifier according to claim 5, characterized in that, The surface shot peening treatment of the rare earth alloy crystal rod includes: The rare earth alloy crystal rod is subjected to surface shot peening treatment using a shot with a first preset diameter value. The shot velocity is a first preset velocity value, the shot peening angle is a first preset angle value, the shot peening coverage is >100%, and the thickness of the surface layer of the rare earth alloy crystal rod that causes plastic deformation is a first preset thickness value.

7. The method for preparing the antioxidant rare earth alloy modifier according to claim 6, characterized in that, The first preset diameter value has a range of 0.1mm to 4mm; The first preset speed value has a range of 40m / s to 120m / s; The first preset angle value has a range of 60° to 90°. The first preset thickness value has a range of 0.1mm to 2mm.

8. The method for preparing the antioxidant rare earth alloy modifier according to claim 6, characterized in that, The projectile is made of cast steel, cast iron, or ceramic.

9. The method for preparing the antioxidant rare earth alloy modifier according to claim 5, characterized in that, The step of subjecting the shot-peened rare earth alloy crystal rod to protective atmosphere heat treatment includes: Under a preset protective atmosphere, the rare earth alloy crystal rod after shot peening is subjected to recrystallization heat treatment at a first preset temperature value and held at that temperature for a first preset time to obtain an antioxidant rare earth alloy modifier with a fine-grained surface and columnar crystals inside.

10. The method for preparing the antioxidant rare earth alloy modifier according to claim 9, characterized in that, The first preset temperature value has a range of 300℃ to 1200℃; The first preset duration ranges from 15 min to 120 min; The preset protective atmosphere includes at least one of argon, helium, and nitrogen.

Images