A hot-corrosion-resistant nickel-based superalloy plate and a preparation method thereof

Abstract

The application discloses a kind of anti-thermal corrosion nickel-based superalloy plate and preparation method thereof, it is related to nickel-based superalloy technical field.The application includes: S1: raw materials such as nickel, chromium, cobalt, molybdenum are smelted and alloyed by adding aluminum, titanium, to obtain alloy melt;S2: before casting, pre-prepared anti-liquefaction crack additive is added to the melt, and after stirring and dispersing, it is cast into ingot;The additive is prepared by high-energy ball milling, cold pressing and vacuum reaction sintering of tantalum, boron, zirconium and yttrium powder, so that boron and zirconium are locked in nanoscale high-melting-point solid-phase particles;S3: the ingot is sequentially remelted, annealed, hot-rolled and heat treated.The application uses pre-prepared carrier particles, which keeps the grain boundary solidly connected during welding, preventing the formation of liquid cracks.The combustion chamber structure made in this way can rely on the strength of complete weld to support in the high-temperature environment of engine ignition operation, avoiding structural failure caused by micro-crack propagation.

Description

Technical Field

[0001] This invention relates to the field of nickel-based superalloys, and more particularly to a hot corrosion resistant nickel-based superalloy sheet and its preparation method. Background Technology

[0002] Nickel-based superalloys can operate for extended periods in high-temperature and complex stress environments exceeding 600°C. Due to their excellent high-temperature strength, toughness, and corrosion resistance, these materials are widely used in the manufacture of core hot-end components such as combustion chambers and turbine disks for aero-engines and ground-based gas turbines. To improve engine efficiency and allow these components to withstand even higher operating temperatures, trace amounts of boron and zirconium are typically added to the alloy. These elements accumulate at the grain boundaries within the alloy, inhibiting grain slip deformation at high temperatures and thus improving the alloy's high-temperature creep life and creep resistance.

[0003] This strengthening method has significant technological limitations in actual production. During the solidification of the alloy melt, boron and zirconium elements accumulate in the grain boundary regions that are the last to solidify, and react with the matrix element nickel to form a low-melting-point eutectic structure. This means that although the alloy matrix can withstand temperatures above 1300℃, the grain boundary regions will melt at around 1100℃.

[0004] This physical property directly affects subsequent component welding processes. When high-temperature alloy plates are welded into structural components such as combustion chamber cylinders, the high temperature of the welding arc is conducted to the heat-affected zone (HAZ) around the weld. Once the temperature of the HAZ exceeds the melting point of the low-melting-point microstructure at the grain boundaries, the grain boundaries transform into a liquid film, causing the intergranular bonding strength to disappear. At this point, the thermal stress generated during the welding process will pull apart these liquefied grain boundaries, forming irreparable welding liquefaction cracks.

[0005] Under current technological conditions, it is difficult to simultaneously achieve high-temperature strength and weldability in alloys. To ensure a high welding success rate, the amount of boron and zirconium added is usually reduced, but this directly decreases the high-temperature performance of the alloy. If a high-strength alloy formulation is insisted upon, extremely costly and specialized welding processes must be employed, which limits the large-scale application of high-performance nickel-based superalloys. Summary of the Invention

[0006] In view of the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is the liquefaction cracking problem in the weld heat-affected zone caused by the formation of a low-melting-point eutectic structure at the grain boundaries when using boron and zirconium elements to strengthen the grain boundaries of nickel-based superalloy plates.

[0007] To achieve the above objectives, the present invention provides a hot corrosion resistant nickel-based high-temperature alloy sheet, wherein the sheet is composed of the following chemical components by weight percentage: chromium 18.0%-22.0%, cobalt 10.0%-15.0%, molybdenum 3.0%-5.0%, titanium 2.5%-3.5%, aluminum 1.2%-1.8%, anti-liquefaction cracking additive 0.5%-1.2%, and the balance being nickel and unavoidable impurities;

[0008] The preparation of the anti-liquefaction cracking additive includes the following steps:

[0009] P1. Mix the raw material powders composed of tantalum, boron, zirconium and yttrium under an inert atmosphere;

[0010] P2. The mixed powder is subjected to high-energy mechanical ball milling to form composite powder;

[0011] P3. The composite powder is cold-pressed to obtain a blank;

[0012] P4. The green body is subjected to reaction sintering in a vacuum environment to obtain the anti-liquefaction cracking additive.

[0013] In a preferred embodiment of the present invention, the anti-liquefaction cracking additive is prepared from the following raw material powder by weight percentage:

[0014] Tantalum 50%-60%, Boron 10%-15%, Zirconium 15%-20%, Yttrium 10%-15%.

[0015] In a preferred embodiment of the present invention, in step P2, the process parameters of the high-energy mechanical ball mill are: ball-to-material mass ratio of 10:1-15:1, rotation speed of 350 r / min-450 r / min, and time of 20 h-30 h.

[0016] In a preferred embodiment of the present invention, in step P3, the pressure of the cold pressing is 150MPa-200MPa.

[0017] In a preferred embodiment of the present invention, in step P4, the process parameters for the reaction sintering are: vacuum degree. The sintering temperature is 1300℃-1400℃, and the holding time is 2h-4h.

[0018] In a preferred embodiment of the present invention, the anti-liquefaction cracking additive is dispersed in the matrix of the plate in the form of nanoscale composite particles with an average particle size of 50nm-500nm.

[0019] In a preferred embodiment of the present invention, the final weight percentage of boron in the plate is 0.005%-0.02%, and the final weight percentage of zirconium is 0.01%-0.06%.

[0020] This invention also provides a method for preparing a hot-corrosion resistant nickel-based superalloy plate, comprising the following steps:

[0021] S1. Nickel, chromium, cobalt and molybdenum are melted and refined in a vacuum induction melting furnace, and then aluminum and titanium are added to alloy them to obtain an alloy melt;

[0022] S2. Before casting, the pre-made anti-liquefaction cracking additive is added to the alloy melt and stirred to disperse it. Then the casting is completed to obtain an ingot.

[0023] S3. The ingot is subjected to vacuum arc remelting, homogenization annealing, hot rolling, solution treatment and aging treatment in sequence to obtain the plate.

[0024] In a preferred embodiment of the present invention, in step S2, the anti-liquefaction cracking additive is added 2-5 minutes before casting.

[0025] In a preferred embodiment of the present invention, in step S3, the temperature of the solution treatment is 1050℃-1100℃, and the temperature of the aging treatment is 700℃-800℃.

[0026] The apparatus or method provided by this invention has the following technical effects:

[0027] 1. Through high-energy mechanical ball milling and reactive sintering, tantalum metal reacts chemically with boron and zirconium to generate a grain boundary solid-phase carrier with a high-melting-point tantalum boride phase as its core. Adding this carrier to a nickel-based alloy melt produces a novel high-temperature alloy sheet. In this sheet, boron and zirconium no longer exist as free atoms but are locked within highly thermally stable particles. When this sheet is used to weld products such as aero-engine combustors, even if the high temperature generated by the welding arc is conducted to the heated weld zone, these carrier particles will not melt or release boron to form a low-melting-point liquid film. This ensures that the grain boundaries remain solid-state during welding, preventing the formation of liquefaction cracks. Combustion chamber structural components manufactured in this way can rely on the strength of the intact weld to withstand the high temperatures of engine ignition, avoiding structural failure caused by the propagation of microcracks.

[0028] 2. Utilizing the dispersed distribution characteristics of the grain boundary solid-phase carrier within the alloy matrix, an alloy material with a composite strengthening structure was fabricated. Although boron and zirconium elements in the carrier particles are locked, these nanoscale particles are distributed within the grain boundaries and grains, preventing grain boundary sliding under high-temperature loads. This physical barrier ensures that the plate does not easily undergo creep deformation under prolonged heating. Simultaneously, the active element yttrium contained in the carrier migrates to the material surface during service, enhancing the adhesion between the surface chromium oxide scale and the metal matrix, preventing the protective film from easily peeling off when operating in environments containing salt spray or sulfur gases. Gas turbine blades or guide vanes made from this material maintain dimensional stability and resist chemical corrosion under the dual effects of high-temperature corrosion and complex stress, significantly extending the service life of hot-end components under harsh operating conditions.

[0029] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0030] Figure 1 This is a scanning electron microscope (SEM) microstructure image of the weld heat-affected zone, which is a comparative example of the present invention.

[0031] Figure 2 This is a transmission electron microscope (TEM) microstructure image of the weld heat-affected zone in Embodiment 1 of the present invention;

[0032] Figure 3 This is a scanning electron microscope (SEM) microstructure image of the weld heat-affected zone in Comparative Example 2 of this invention. Detailed Implementation

[0033] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0034] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the shape, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0035] Some exemplary embodiments of the invention have been described for illustrative purposes. It should be understood that the invention may be implemented in other ways not specifically shown in the accompanying drawings.

[0036] This invention provides a heat-corrosion resistant nickel-based high-temperature alloy sheet and its preparation method.

[0037] The aforementioned heat-corrosion-resistant nickel-based high-temperature alloy sheet comprises, by weight percentage: 18.0%-22.0% chromium, 10.0%-15.0% cobalt, 3.0%-5.0% molybdenum, 2.5%-3.5% titanium, 1.2%-1.8% aluminum, and a specially prepared anti-liquefaction cracking additive of 0.5%-1.2%, with the balance being nickel and impurities unavoidably introduced during the production process. By controlling the amount of the above additives, the weight percentage of boron in the final sheet can be controlled at 0.005%-0.02%, and the weight percentage of zirconium at 0.01%-0.06%.

[0038] The core of this invention lies in the design and preparation of the aforementioned anti-liquefaction cracking additive. It is not a simple mixture of elements, but a composite material pre-synthesized through a specific process, the preparation process of which is as follows:

[0039] First, the raw materials are precisely proportioned and mixed. Tantalum powder, which serves as the high-melting-point framework, boron and zirconium powders, which provide grain boundary strengthening, and yttrium powder, which has both purifying and antioxidant properties, are weighed according to specific weight percentages (tantalum 50%-60%, boron 10%-15%, zirconium 15%-20%, yttrium 10%-15%). To prevent the highly reactive zirconium and yttrium powders from being oxidized during mixing, the entire mixing process is carried out in an inert atmosphere filled with high-purity argon.

[0040] After mixing, the crucial high-energy mechanical ball milling step begins. The mixed powder is placed in a high-energy planetary ball mill and milled for 20 to 30 hours at a ball-to-powder mass ratio of 10:1 to 15:1 and a rotation speed of 350 to 450 rpm. This process is not a simple physical mixing, but a mechanical alloying process. Under high-energy impact, the powder particles undergo repeated cold welding, fracture, and re-welding, promoting forced solid solution at the atomic level or the formation of nanoscale metastable intermetallic compounds. The purpose of this step is to "pre-capture" elements such as boron and zirconium at the atomic scale and tightly bond them with tantalum, providing a huge chemical reaction potential for subsequent reaction sintering.

[0041] The ball-milled composite powder possesses extremely high activity and a very fine particle size, requiring densification through cold pressing. The composite powder is pressed under a pressure of 150 MPa to 200 MPa to obtain cylindrical or block-shaped blanks with a certain mechanical strength. This step ensures close contact between particles during subsequent sintering, facilitating atomic diffusion and sufficient chemical reactions.

[0042] Finally, the green body is subjected to vacuum reaction sintering. The green body is placed in a vacuum with a degree of not less than [missing information]. In a high vacuum environment, the temperature is raised to 1300℃-1400℃ and held for 2 to 4 hours. Under high temperature and vacuum conditions, the metastable structure formed during ball milling undergoes a chemical reaction, transforming into thermodynamically extremely stable high-melting-point compounds, primarily tantalum boride. The final product of this step is the anti-liquefaction cracking additive required in this invention.

[0043] When this additive is added to the final nickel-based alloy, it does not completely decompose into individual atoms, but rather is uniformly dispersed in the nickel matrix as nanoscale composite particles with an average particle size in the range of 50 nm to 500 nm.

[0044] The final alloy sheet preparation process was also meticulously designed:

[0045] The initial step is the preparation of the alloy melt. Using vacuum induction melting technology, nickel, which serves as the matrix, along with high-melting-point elements such as chromium, cobalt, and molybdenum, are first added to the furnace for melting and refining to remove gases and impurities. Subsequently, chemically reactive aluminum and titanium are added; these are not only key elements for forming the strengthening phase but also further remove oxygen from the melt.

[0046] Then, in the last 2 to 5 minutes before alloying and casting, the pre-prepared block-shaped anti-liquefaction cracking additive is added to the alloy melt through a feeder, and electromagnetic stirring is used to rapidly disperse it. The principle of choosing this short time window is to control it using reaction kinetics: this time is sufficient for the additive to be macroscopically uniformly distributed, but not enough for the structurally stable tantalum boride nanoparticles to completely decompose in the high-temperature melt and release free boron atoms.

[0047] The homogeneous melt is then cast into ingots. To further improve the purity and uniformity of the alloy, the ingots undergo vacuum arc remelting.

[0048] Finally, the forming and performance determination of the sheet metal are addressed. The remelted ingot undergoes homogenization annealing to eliminate compositional segregation, and then is hot-rolled in multiple passes to produce sheets of the required thickness. The final mechanical properties of the sheet metal are obtained through a two-step heat treatment: first, solution treatment at 1050℃-1100℃ allows the strengthening elements to fully dissolve into the nickel matrix, forming a supersaturated solid solution; then, a long-term aging treatment at 700℃-800℃ further strengthens the titanium, aluminum, and other elements. The γ' phase precipitates out in the form of a diffusely distributed γ' reinforcing phase, thereby giving the board excellent high-temperature strength.

[0049] Example 1

[0050] This embodiment provides a hot-corrosion resistant nickel-based high-temperature alloy plate and its preparation method.

[0051] I. Preparation of Anti-liquefaction Crack Additives

[0052] 1. Raw material composition (weight percentage)

[0053] Tantalum powder 55%, boron powder 12.5%, zirconium powder 17.5%, yttrium powder 15%.

[0054] 2. Preparation steps

[0055] (1) The above raw material powder is mechanically mixed in a glove box filled with high-purity argon for 30 minutes.

[0056] (2) The mixed powder was loaded into a stainless steel ball mill jar and subjected to high-energy mechanical ball milling on a planetary ball mill. The process parameters were set as follows: ball-to-material mass ratio 12.5:1, rotation speed 400 r / min, and grinding time 25 hours.

[0057] (3) Take out the ball-milled composite powder and perform cold isostatic pressing at a pressure of 175 MPa for 10 minutes to obtain a block blank.

[0058] (4) Place the billet in a high vacuum sintering furnace, where the vacuum level is better than that of the billet. Under certain conditions, the temperature is raised to 1350℃ and held at this temperature for 3 hours. After cooling in the furnace, the antioxidant crack-resistant additive is obtained.

[0059] II. Preparation of Heat Corrosion Resistant Nickel-Based High-Temperature Alloy Sheets

[0060] 1. Raw material composition (weight percentage)

[0061] Chromium 20.0%, Cobalt 12.5%, Molybdenum 4.0%, Titanium 3.0%, Aluminum 1.5%, Anti-liquefaction cracking additive 0.8%, balance is nickel and unavoidable impurities.

[0062] 2. Preparation steps

[0063] (1) A vacuum induction melting furnace is used to melt nickel, chromium, cobalt, and molybdenum. The mixture is heated and melted under vacuum and then refined. Subsequently, aluminum and titanium are added to alloy the mixture, resulting in an alloy melt.

[0064] (2) Three minutes before casting, the block anti-liquefaction cracking additive prepared in step one is added to the alloy melt through a feeder and then evenly dispersed by electromagnetic stirring.

[0065] (3) Cast the melt into a cylindrical ingot with a diameter of 150 mm.

[0066] (4) The ingot is used as a consumable electrode and remelted in a vacuum consumable remelting furnace to purify and refine the microstructure.

[0067] (5) The remelted ingot is subjected to homogenization annealing at 1180℃ for 24 hours.

[0068] (6) The annealed ingot is hot rolled in multiple passes to make a plate with a thickness of 5mm.

[0069] (7) Perform final heat treatment on the plate: first, perform solution treatment at 1080℃ for 1 hour and water quench, then perform aging treatment at 760℃ for 8 hours and air cool.

[0070] Example 2

[0071] This embodiment provides a hot-corrosion resistant nickel-based high-temperature alloy plate and its preparation method.

[0072] I. Preparation of Anti-liquefaction Crack Additives

[0073] 1. Raw material composition (weight percentage)

[0074] 50% tantalum powder, 10% boron powder, 25% zirconium powder, and 15% yttrium powder.

[0075] 2. Preparation steps

[0076] (1) The steps are exactly the same as in Example 1.

[0077] (2) The mixed powder was loaded into a stainless steel ball mill jar and subjected to high-energy mechanical ball milling on a planetary ball mill. The process parameters were set as follows: ball-to-material mass ratio 10:1, rotation speed 350 r / min, and grinding time 20 hours.

[0078] (3) Take out the ball-milled composite powder and perform cold isostatic pressing at a pressure of 150 MPa for 10 minutes to obtain a block blank.

[0079] (4) Place the billet in a high vacuum sintering furnace, where the vacuum level is better than that of the billet. Under certain conditions, the temperature is raised to 1300℃ and held at this temperature for 2 hours. After cooling in the furnace, the anti-liquefaction cracking additive is obtained.

[0080] II. Preparation of Heat Corrosion Resistant Nickel-Based High-Temperature Alloy Sheets

[0081] 1. Raw material composition (weight percentage)

[0082] Chromium 18.0%, Cobalt 10.0%, Molybdenum 3.0%, Titanium 2.5%, Aluminum 1.2%, Anti-liquefaction cracking additive 0.5%, balance is nickel and unavoidable impurities.

[0083] 2. Preparation steps

[0084] Steps (1) to (7) are exactly the same as in Example 1.

[0085] Example 3

[0086] This embodiment provides a hot-corrosion resistant nickel-based high-temperature alloy plate and its preparation method.

[0087] I. Preparation of Anti-liquefaction Crack Additives

[0088] 1. Raw material composition (weight percentage)

[0089] 60% tantalum powder, 15% boron powder, 15% zirconium powder, and 10% yttrium powder.

[0090] 2. Preparation steps

[0091] (1) The steps are exactly the same as in Example 1.

[0092] (2) The mixed powder was loaded into a stainless steel ball mill jar and subjected to high-energy mechanical ball milling on a planetary ball mill. The process parameters were set as follows: ball-to-material mass ratio 15:1, rotation speed 450 r / min, and grinding time 30 hours.

[0093] (3) Take out the ball-milled composite powder and perform cold isostatic pressing at a pressure of 200 MPa for 10 minutes to obtain a block blank.

[0094] (4) Place the billet in a high vacuum sintering furnace, where the vacuum level is better than that of the billet. Under certain conditions, the temperature is raised to 1400°C and held at this temperature for 4 hours. After cooling in the furnace, the anti-liquefaction cracking additive is obtained.

[0095] II. Preparation of Heat Corrosion Resistant Nickel-Based High-Temperature Alloy Sheets

[0096] 1. Raw material composition (weight percentage)

[0097] Chromium 22.0%, Cobalt 15.0%, Molybdenum 5.0%, Titanium 3.5%, Aluminum 1.8%, Anti-liquefaction cracking additive 1.2%, balance is nickel and unavoidable impurities.

[0098] 2. Preparation steps

[0099] Steps (1) to (7) are exactly the same as in Example 1.

[0100] Comparative Example 1

[0101] This comparative example provides a nickel-based high-temperature alloy sheet and its preparation method.

[0102] I. Preparation of Nickel-Based High-Temperature Alloy Plates

[0103] 1. Raw material composition (weight percentage)

[0104] Chromium 20.0%, Cobalt 12.5%, Molybdenum 4.0%, Titanium 3.0%, Aluminum 1.5%, Tantalum 0.44%, Boron 0.10%, Zirconium 0.14%, Yttrium 0.12%, with the balance being nickel and unavoidable impurities.

[0105] 2. Preparation steps

[0106] (1) The steps are exactly the same as in Example 1.

[0107] (2) Three minutes before casting, tantalum, boron, zirconium and yttrium are added to the alloy melt in the form of pure metal or intermediate alloy through a feeder and are evenly dispersed by electromagnetic stirring.

[0108] Steps (3) to (7) are exactly the same as in Example 1.

[0109] Comparative Example 2

[0110] This comparative example provides a nickel-based high-temperature alloy sheet and its preparation method.

[0111] I. Preparation of Physically Mixed Additives

[0112] 1. Raw material composition (weight percentage)

[0113] The composition includes 55% tantalum powder, 12.5% ​​boron powder, 17.5% zirconium powder, and 15% yttrium powder.

[0114] 2. Preparation steps

[0115] (1) The steps are exactly the same as in Example 1.

[0116] (2) The powder mixed in step (1) is subjected to cold isostatic pressing at a pressure of 175 MPa and held for 10 minutes to obtain a block-shaped physical mixture additive.

[0117] II. Preparation of Heat Corrosion Resistant Nickel-Based High-Temperature Alloy Sheets

[0118] 1. Raw material composition (weight percentage)

[0119] Chromium 20.0%, Cobalt 12.5%, Molybdenum 4.0%, Titanium 3.0%, Aluminum 1.5%, Physically mixed additives 0.8%, Balance nickel and unavoidable impurities.

[0120] 2. Preparation steps

[0121] (1) The steps are exactly the same as in Example 1.

[0122] (2) Three minutes before casting, the blocky physical mixing additives prepared in step one are added to the alloy melt through a feeder and then evenly dispersed by electromagnetic stirring.

[0123] Steps (3) to (7) are exactly the same as in Example 1.

[0124] Comparative Example 3

[0125] This comparative example provides a nickel-based high-temperature alloy sheet and its preparation method.

[0126] I. Preparation without tantalum additives

[0127] 1. Raw material composition (weight percentage)

[0128] Boron powder 27.8%, zirconium powder 38.9%, yttrium powder 33.3%.

[0129] 2. Preparation steps

[0130] (1) The above raw material powder is mechanically mixed in a glove box filled with high-purity argon for 30 minutes.

[0131] Steps (2) to (4) are exactly the same as in Example 1.

[0132] II. Preparation of Heat Corrosion Resistant Nickel-Based High-Temperature Alloy Sheets

[0133] 1. Raw material composition (weight percentage)

[0134] Chromium 20.0%, Cobalt 12.5%, Molybdenum 4.0%, Titanium 3.0%, Aluminum 1.5%, Tantalum-free additive 0.8%, Balance is nickel and unavoidable impurities.

[0135] 2. Preparation steps

[0136] (1) The steps are exactly the same as in Example 1.

[0137] (2) Three minutes before casting, the blocky tantalum-free additives obtained in step one are added to the alloy melt through a feeder and then evenly dispersed by electromagnetic stirring.

[0138] Steps (3) to (7) are exactly the same as in Example 1.

[0139] To verify the beneficial effects of the present invention, the test samples were prepared as follows: Six different groups of nickel-based superalloy plates were prepared according to the complete preparation processes described in Examples 1, 2, and 3, and Comparative Examples 1, 2, and 3. These six groups of plates were sequentially labeled E1, E2, E3, and C1, C2, C3. Subsequently, standard test specimens were prepared from all groups of plates according to the standard requirements for each performance test, and the following performance tests were performed on all prepared test specimens.

[0140] (1) Welding crack sensitivity test

[0141] The evaluation of weld crack susceptibility employs the internationally recognized Varestraint Test method. This test applies a precisely controlled strain to the weld and heat-affected zone via a bending base while the plate sample undergoes automated tungsten inert gas (TIG) welding. This test quantitatively evaluates the material's resistance to weld hot cracking by directly inducing crack initiation. The quantitative indicator is the total crack length (TCL), measured in millimeters (mm). A shorter TCL indicates a stronger resistance to cracking under welding thermal cycles and stress, directly corresponding to better weldability, higher component yield, and more reliable weld joint quality in practical engineering manufacturing.

[0142] (2) High-temperature durability test

[0143] The high-temperature creep life test follows the Chinese national standard GB / T2039-2012, "Metallic Materials - Uniaxial Tensile Creep Test Method," which is currently in effect. Sheet metal is processed into standard-sized tensile specimens and placed in a high-temperature creep testing machine. The test is conducted at a constant temperature of 1200℃ and a constant axial tensile stress of 150 MPa until the specimen fractures. The quantitative evaluation index is the fracture time, expressed in hours (h). A longer fracture time indicates a stronger ability of the material to resist plastic deformation and damage accumulation under the combined effects of high temperature and stress. This directly reflects the longer service life and higher reliability of hot-end components made from this alloy.

[0144] (3) Test of resistance to thermal corrosion

[0145] The testing of hot corrosion resistance was conducted in accordance with the Chinese aviation industry standard HB5258-1983, "Test Method for Hot Corrosion of High-Temperature Alloys." This standard is the authoritative method widely followed in the domestic high-temperature alloy field for such tests. During the test, a layer of 75% sodium sulfate was pre-coated onto the surface of the cut sheet-like sample. ) and 25% sodium chloride ( A mixed salt was applied, with a salt concentration of approximately 2 mg / cm². The sample was then subjected to cyclic corrosion in a muffle furnace at 900°C, holding for 20 hours per cycle before air cooling. After each cycle, corrosion products were removed by cleaning, and the sample was accurately weighed. The quantitative indicator for evaluation was the corrosion weight loss rate, expressed in milligrams per square centimeter per hour (mg / cm²). The smaller the absolute value of the corrosion-weight loss rate, the stronger the material's ability to resist chemical corrosion and oxide spalling in a high-temperature molten salt environment. This corresponds to the alloy having stronger environmental adaptability in harsh combustion atmospheres containing impurities such as sulfur and chlorine.

[0146] (4) Microstructure analysis of the heat-affected zone of welding

[0147] To elucidate the intrinsic mechanism by which this invention suppresses welding cracks, the microstructure of the heat-affected zone (HAZ) after welding was observed. The sample preparation and testing methods followed the Chinese national standard GB / T13298-2015, "Metallic Materials - Microstructure Testing Methods," which is currently in effect. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyze the phase morphology, size, and elemental distribution in and around the grain boundaries. Key evidence in the analysis lies in identifying the morphology and composition of the precipitates at the grain boundaries. In conventional alloys, a continuous, low-melting-point eutectic film rich in nickel and boron is observed at the grain boundaries. However, in the alloy prepared according to this invention, dispersed, nanoscale-sized, high-melting-point composite particles rich in tantalum and boron are observed at the grain boundaries. This fundamental difference in microstructure directly demonstrates the mechanism by which this invention suppresses grain boundary liquefaction by altering the form in which boron exists.

[0148] The above performance was tested, and the results are summarized in the table below:

[0149]

[0150] (1) Welding crack sensitivity analysis

[0151] The data in Table 1 show that the total crack length of Examples E1 to E3 ranges from 1.4 mm to 2.6 mm, while the total crack length of Comparative Example C1 is 14.5 mm. This indicates that the preparation method of the present invention can reduce the total crack length of the material by more than 80% compared to conventional addition methods. This performance difference is related to... Figure 1 and Figure 2 The microstructure shown corresponds to this. Figure 1 The results show that a continuous low-melting-point eutectic film exists at the grain boundaries of C1. Figure 2This indicates that no continuous thin film structure was observed at the grain boundaries of E1. Furthermore, the TCLs of comparative examples C2 and C3 were 13.2 mm and 16.8 mm, respectively, demonstrating that high-energy mechanical ball milling and reactive sintering processes, along with the presence of tantalum, are necessary conditions for reducing weld crack susceptibility.

[0152] (2) High-temperature durability analysis

[0153] Regarding high-temperature creep life, the fracture time of Example E1 was 54.5 hours, which is on par with the 52.0 hours of Comparative Example C1. This indicates that the preparation method of the present invention improves weldability while maintaining the high-temperature creep performance of the material. The fracture times of Examples E2 and E3 were 51.2 hours and 58.3 hours, respectively. The data shows that the creep life increases with the increase of the amount of additive, which is consistent with the influence of the reinforcing phase content on high-temperature strength.

[0154] (3) Analysis of hot corrosion resistance

[0155] The results of the hot corrosion resistance test showed that the corrosion weight loss rate of Examples E1 to E3 ranged from 0.06 to 0.11. Within this range, the comparative corrosion weight loss rate was between 0.17 and 0.19. Within the specified range. The lower corrosion weight loss rate in the embodiment is due to the introduction of yttrium into the additives. Through high-energy mechanical ball milling, the yttrium-containing phase can be more uniformly distributed in the alloy matrix, which helps to form a protective oxide film at high temperatures.

[0156] (4-1) Microstructure analysis of the heat-affected zone of welding

[0157] Microscopic observations explained the source of differences in macroscopic performance. For example... Figure 1 As shown, comparative example C1 exhibits continuous low-melting-point grain boundaries. The eutectic phase corresponds to the sample's high weld crack susceptibility (TCL=14.5mm). In contrast, Figure 2 In Example E1, no continuous eutectic film was observed at the grain boundaries; instead, dispersed nanoscale TaB particles were distributed. The presence of this high-melting-point particle structure allows the material to maintain grain boundary stability at welding high temperatures, corresponding to its low weld crack sensitivity (TCL=1.8mm). Figure 3 The microstructure of the comparative example C2, containing both unreacted particles and discontinuous eutectic films, indicates that effective bonding of boron and tantalum could not be achieved through physical mixing alone. This microstructure explains why its weldability falls between that of E1 and C1, and underscores the necessity of the high-energy mechanical ball milling and reactive sintering steps.

[0158] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A heat-corrosion resistant nickel-based high-temperature alloy sheet, characterized in that, The plate is composed of the following chemical components by weight percentage: chromium 18.0%-22.0%, cobalt 10.0%-15.0%, molybdenum 3.0%-5.0%, titanium 2.5%-3.5%, aluminum 1.2%-1.8%, anti-liquefaction cracking additive 0.5%-1.2%, and the balance being nickel and unavoidable impurities; The anti-liquefaction cracking additive is prepared from the following raw material powders by weight percentage: Tantalum 50%-60%, Boron 10%-15%, Zirconium 15%-20%, Yttrium 10%-15%; The preparation of the anti-liquefaction cracking additive includes the following preparation steps: P1. Mix the raw material powders composed of tantalum, boron, zirconium and yttrium under an inert atmosphere; P2. The mixed powder is subjected to high-energy mechanical ball milling to form composite powder; P3. The composite powder is cold-pressed to obtain a blank; P4. The green body is subjected to reaction sintering in a vacuum environment to obtain the anti-liquefaction cracking additive; Furthermore, the anti-liquefaction cracking additive is diffusely distributed in the matrix of the plate in the form of nanoscale composite particles with an average particle size of 50nm-500nm.

2. The heat-corrosion resistant nickel-based high-temperature alloy sheet according to claim 1, characterized in that, In step P2, the process parameters for the high-energy mechanical ball mill are: ball-to-material mass ratio of 10:1-15:1, rotation speed of 350 r / min-450 r / min, and time of 20 h-30 h.

3. The heat-corrosion resistant nickel-based high-temperature alloy sheet according to claim 1, characterized in that, In step P3, the pressure of the cold pressing is 150MPa-200MPa.

4. The hot corrosion resistant nickel-based high-temperature alloy sheet according to claim 1, characterized in that, In step P4, the process parameters of the reaction sintering are: vacuum degree ≤10 -2 Pa, sintering temperature is 1300℃-1400℃, and holding time is 2h-4h.

5. The hot corrosion resistant nickel-based high-temperature alloy sheet according to claim 1, characterized in that, In the plate, the final weight percentage of boron is 0.005%-0.02%, and the final weight percentage of zirconium is 0.01%-0.06%.

6. A method for preparing a hot-corrosion resistant nickel-based superalloy sheet according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Nickel, chromium, cobalt and molybdenum are melted and refined in a vacuum induction melting furnace, and then aluminum and titanium are added to alloy them to obtain an alloy melt; S2. 2-5 minutes before casting, add the pre-made anti-liquefaction cracking additive to the alloy melt and stir to disperse it, then complete the casting to obtain an ingot; S3. The ingot is subjected to vacuum arc remelting, homogenization annealing, hot rolling, solution treatment and aging treatment in sequence to obtain the plate.

7. The method according to claim 6, characterized in that, In step S3, the solution treatment temperature is 1050℃-1100℃, and the aging treatment temperature is 700℃-800℃.

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