A nickel-based wrought superalloy and method of manufacture

Abstract

The present application relates to a kind of nickel-based wrought superalloy and preparation method, belong to nickel-based wrought superalloy design and preparation technical field, solve the problem that the purity of existing nickel-based wrought superalloy is difficult to control, strengthening element segregation is serious, dendritic organization is bulky.The alloy chemical composition is as follows by mass percent:Y:0.005~0.15%, Co:14.0~16.0%, Cr:10~12%, W:2.5~3.5%, Mo:4.0~5.0%, Al:3.5~4.0%, Ti:2.5~3.1%, Nb:3.0~3.5%, V:0.4~0.8%, C:0.01~0.08%, B:0.005~0.02%, the rest is Ni and inevitable impurity;Y+Ti+Nb+Mo+W is 13~14% by mass percent.

Description

Technical Field

[0001] This invention relates to the field of nickel-based wrought superalloy design and preparation technology, and particularly to a nickel-based wrought superalloy and its preparation method. Background Technology

[0002] Nickel-based wrought superalloys exhibit excellent high-temperature strength, creep resistance, fatigue resistance, and oxidation resistance, making them widely used in the manufacture of hot-end components for aero-engines and gas turbines. This superior high-temperature performance is attributed to the high purity of these alloys and the presence of numerous strengthening elements, such as Co, Cr, W, Mo, Al, Ti, and Nb.

[0003] With the continuous development of the aviation industry and the continuous improvement of engine performance, higher requirements are placed on the heat resistance of nickel-based wrought superalloys. In order to improve the heat resistance of nickel-based wrought superalloys, existing methods generally increase the types and contents of strengthening elements in the alloy. However, although the heat resistance of nickel-based wrought superalloys is improved, the purity control of the superalloy becomes more difficult, and the segregation of added strengthening elements (such as W, Mo, Ti, Nb, etc.) becomes more serious, resulting in poor metallurgical quality and compositional uniformity of the alloy, which brings difficulties to the subsequent smelting and hot working of ingots. Furthermore, high alloying leads to the complexity of the solidification process, making it easy for coarse dendritic structures to appear in the ingots, further deteriorating the microstructure and properties of the ingots.

[0004] In high-temperature alloys, the addition of trace elements can significantly affect their microstructure and properties. However, there are many types of trace elements, and their effects and mechanisms in different alloy systems are complex. The effects of different types of trace elements vary in different alloy systems, making the selection of suitable trace element types and contents challenging. Therefore, how to rationally utilize trace elements and optimize the composition and preparation methods of nickel-based wrought superalloys to improve their metallurgical quality, microstructure, and compositional uniformity is a technical challenge that needs to be addressed in this field. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide a nickel-based wrought superalloy and its preparation method, at least to solve one of the following problems existing in the preparation of nickel-based wrought superalloys: 1. The increased variety and content of strengthening elements in existing nickel-based superalloys make it difficult to control the purity of the alloy; 2. The severe segregation of strengthening elements in nickel-based superalloys causes a deterioration in the metallurgical quality and compositional uniformity of the alloy; 3. Coarse dendritic structures are prone to appear in nickel-based superalloys, which deteriorates the microstructure and properties of the alloy.

[0006] The objective of this invention is mainly achieved through the following technical solutions: This invention provides a nickel-based wrought superalloy with the following chemical composition by mass percentage: Y: 0.005–0.15%, Co: 14.0–16.0%, Cr: 10–12%, W: 2.5–3.5%, Mo: 4.0–5.0%, Al: 3.5–4.0%, Ti: 2.5–3.1%, Nb: 3.0–3.5%, V: 0.4–0.8%, C: 0.01–0.08%, B: 0.005–0.02%, with the remainder being Ni and unavoidable impurities; The mass percentage of Y+Ti+Nb+Mo+W is 13-14%.

[0007] Furthermore, the contents of W and Mo satisfy the following conditions: 7% ≤ W + Mo ≤ 8%, W / Mo ≥ 0.6.

[0008] Furthermore, the contents of Y and C satisfy the condition: 0.2 ≤ Y / C ≤ 5.

[0009] Furthermore, the contents of Y and B satisfy the following condition: 1 ≤ Y / B ≤ 15.

[0010] Furthermore, the secondary dendrite spacing in the microstructure of the nickel-based wrought superalloy is 38-47 μm.

[0011] This invention also provides a method for preparing a nickel-based wrought superalloy, which uses the composition design of the above-mentioned nickel-based wrought superalloy and includes the following steps: S1: Preparation of raw materials for smelting. According to the composition requirements of the nickel-based wrought high-temperature alloy, a certain amount of pure metal and / or alloy is weighed as raw materials. The raw materials containing Y element are wrapped with Ni foil and placed into two different feeding chambers of the vacuum induction furnace. The raw materials containing other elements are placed into the crucible of the vacuum induction furnace. The vacuum induction furnace is sealed and vacuum treatment is performed. S2: Raw material melting: The raw materials in the crucible are heated under vacuum conditions to completely melt them into a liquid. S3: Primary refining, which involves refining the molten alloy after the raw materials in the crucible have been completely melted. S4: After the first feeding and refining, the alloy liquid is cooled down. After cooling, argon gas is introduced into the vacuum induction furnace. Then, the raw material containing Y element wrapped in Ni foil in a feeding chamber in the vacuum induction furnace is added to the alloy liquid and the crucible is shaken to carry out heat preservation and impurity removal treatment. S5: Secondary refining, improving the vacuum level and temperature in the vacuum induction furnace to perform secondary refining of the alloy liquid; S6: After the second feeding and refining, the alloy liquid is cooled down. After cooling down, argon gas is introduced into the vacuum induction furnace. Then, the raw material containing Y element wrapped in Ni foil in another feeding chamber in the vacuum induction furnace is added to the alloy liquid and the alloy liquid is electromagnetically stirred at the holding temperature. S7: Casting and unloading: The alloy liquid that has been kept at a constant temperature in step S6 is cast. After casting, it is placed in the furnace for a certain period of time to allow the alloy liquid to completely solidify before being unloaded, thus obtaining the final alloy.

[0012] Further, in step S1, the raw material containing Y element is elemental Y and / or Ni-Y master alloy; Among them, the purity of elemental Y is ≥99.99%, and the mass fraction of Y in the Ni-Y master alloy raw material is 20%-80%; The oxygen content in elemental Y or Ni-Y master alloys shall not exceed 80 ppm; The mass ratio of the raw materials containing Y element in the two feeding bins is 1:1.

[0013] Furthermore, in step S2, the vacuum degree under the vacuum conditions is ≤1 Pa, and the temperature for complete melting is 1500℃~1580℃.

[0014] Furthermore, in step S3, the primary refining temperature is 1450℃~1530℃, the primary refining time is ≥10min, and the primary refining vacuum degree is ≤0.1Pa.

[0015] Further, in step S4, the heat preservation temperature is 1430–1450℃, and the heat preservation time is ≥5 min. Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. This invention controls the content range of easily segregating elements and utilizes the atomic size effect and special physicochemical properties of rare earth element Y to cause Y to segregate at the solid-liquid interface, thereby hindering the diffusion of easily segregating elements into the liquid phase during solidification and reducing segregation. At the same time, Y segregated at the solid-liquid interface can reduce the solid-liquid interface energy, surface tension, and critical nucleation supercooling, thereby promoting grain nucleation during solidification. Combined with a reasonable pouring temperature, it accelerates melt solidification, inhibits segregation, and refines dendrites, realizing the preparation of fine dendrite, low segregation alloys, and significantly improving the metallurgical quality level of the obtained vacuum induction melting alloys.

[0016] 2. This invention adds an appropriate amount of rare earth element Y to a nickel-based wrought superalloy. Utilizing the low free energy of rare earth element Y when combined with impurity elements such as O and S, it forms high-melting-point, low-density inclusions. These inclusions float to the surface in the molten alloy and are removed. Combined with two refining and feeding processes, and precise control of key smelting parameters (refining temperature and time, feeding, and vacuum level), this invention achieves efficient removal of O, S, N, and P from rare earth Y during the metallurgical process, resulting in a high-purity alloy.

[0017] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0018] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0019] Figure 1 The dendritic structure diagram of the alloy prepared in Example 1; Figure 2 The dendritic structure diagram of the alloy prepared in Example 2; Figure 3 The dendritic structure diagram of the alloy prepared in Example 3; Figure 4 The dendritic structure of the alloy prepared in Example 4 is shown in the diagram. Figure 5 The dendritic structure of the alloy prepared in Example 5 is shown in the diagram. Figure 6 The dendritic structure of the alloy prepared in Example 6 is shown in the diagram. Figure 7 The dendritic structure diagram of the alloy prepared in Example 7; Figure 8 Dendritic structure diagram of the alloy prepared in Comparative Example 1; Figure 9 Dendritic structure diagram of the alloy prepared in Comparative Example 2; Figure 10 Dendritic structure diagram of the alloy prepared in Comparative Example 3; Figure 11 The dendritic structure diagram is shown for the alloy prepared in Comparative Example 4. Detailed Implementation

[0020] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0021] This invention provides a nickel-based wrought superalloy with the following chemical composition by mass percentage: Y: 0.005–0.15%, Co: 14.0–16.0%, Cr: 10–12%, W: 2.5–3.5%, Mo: 4.0–5.0%, Al: 3.5–4.0%, Ti: 2.5–3.1%, Nb: 3.0–3.5%, V: 0.4–0.8%, C: 0.01–0.08%, B: 0.005–0.02%, with the remainder being Ni and unavoidable impurities; Preferably, the mass percentage of Y+Ti+Nb+Mo+W is 13-14%; Preferably, 7% ≤ W + Mo ≤ 8%, W / Mo ≥ 0.6; Preferably, 0.2 ≤ Y / C ≤ 5.

[0022] Preferably, 1 ≤ Y / B ≤ 15.

[0023] The reasons for limiting the alloy composition of the above-mentioned nickel-based wrought superalloy and its preparation method in this invention will be explained. Hereinafter, only the percentage of mass in the composition is used.

[0024] Y: Rare earth element Y has high reactivity and can combine with impurity elements such as O, N, and S to form inclusions that can be removed during metallurgical processes, thus purifying the alloy. Simultaneously, during alloy solidification, the large atomic radius of rare earth Y can segregate at the solid-liquid interface, hindering element diffusion, inhibiting element segregation, and promoting nucleation. Rare earth Y can segregate at grain boundaries, reducing grain boundary energy and increasing grain boundary strength. It can also enter carbides, improving their morphology and distribution, thereby enhancing the alloy's creep resistance. However, excessive Y not only expands the solidification range of the alloy, causing more severe segregation, but the high affinity of Y for O causes O adsorption reactions in the alloy melt, contaminating the alloy. Furthermore, the formation of coarse Ni-Y intermetallic compounds by Y and Ni deteriorates mechanical properties. Therefore, in this invention, the Y content is controlled at 0.005–0.15%.

[0025] Co: As the main solid solution strengthening element in nickel-based superalloys, Co dissolves into the matrix to reduce stacking fault energy, thereby effectively improving the strength of the alloy; Co can also replace the main strengthening phase γ The position of the Ni atom in the middle can not only increase the γ at intermediate temperatures The strengthening effect of the phase can also improve the hot plasticity of the alloy at high temperatures; however, the addition of excessive Co will lead to the precipitation of harmful phases, which will damage the mechanical properties of the alloy, and Co is expensive. Therefore, the Co content in this invention is controlled at 14-16.0%.

[0026] Cr: Cr (chromium) causes the alloy to form a Cr₂O₃ oxide film on its surface during high-temperature service, improving its corrosion resistance and oxidation resistance. A low Cr content results in a less dense oxide film with poor oxidation resistance; a Cr content above 10% provides good oxidation resistance. Excessive Cr content leads to increased carbides and decreased microstructural stability, forming a TCP phase and reducing mechanical properties. This invention utilizes the significant effect of rare earth element Y (Y) in enhancing oxidation resistance, combined with a lower limit for Cr content, to improve oxidation resistance and prevent TCP phase formation. Therefore, in this invention, the Cr content is controlled at 10–12%.

[0027] W: The addition of W increases the melting point, oxidation resistance, and corrosion resistance of the alloy. W is also a strong solid solution strengthening element, which is beneficial for improving the alloy's temperature resistance. However, W has a very high tendency to segregate, easily causing W to segregate into the dendrites during solidification, thus forming a large amount of harmful phases such as Laves phase and deteriorating the alloy quality. Therefore, in order to obtain a good strengthening effect and reduce W segregation, the W content in this invention is controlled at 2.5%–3.5%.

[0028] Mo: Mo mainly plays a role in solid solution strengthening in high-temperature alloys, which can improve the high-temperature strength of the alloy; however, Mo is an element that is prone to segregation, and segregation between dendrites will cause the alloy quality to deteriorate. Moreover, a high Mo content will also promote the precipitation of harmful phases during the service of the alloy. Therefore, in this invention, the Mo content is controlled at 4.0-5.0%.

[0029] Al: Al is a strengthening phase in high-temperature alloys. One of the main components, through γ Precipitation phases strengthen the alloy by hindering dislocation movement; however, the strengthening effect is not significant when the Al content is too low, while excessive Al content may cause internal oxidation of the alloy. Therefore, in this invention, the Al content is controlled at 3.5–4%.

[0030] Ti: The addition of Ti can not only increase γ Phase content, and can replace γ The position of Al atoms in the phase increases the reverse domain boundary energy, which can enhance γ. Ti enhances mechanical properties through its strengthening effect; however, it is also a segregating element, segregating into the interdendritic space during solidification and easily forming the η phase (Ni3Ti), which increases the alloy's cracking tendency. Therefore, in this invention, the Ti content is controlled at 2.5–3.1%.

[0031] Nb: Nb is also γ One of the main constituent elements of the phase, γ When Al atoms are replaced by Nb atoms in the phase, their stability is improved, thus enhancing the strengthening effect. Simultaneously, during alloy solidification, the MC carbides formed by the combination of Nb and C not only serve as heterogeneous nucleation to refine dendrites but also increase the alloy's strength. However, Nb is a segregating element; excessive Nb will widen the solidification temperature range of nickel-based superalloys, exacerbating segregation, leading to the formation of a large amount of Laves phase between dendrites, deteriorating alloy quality, and easily causing metallurgical defects. Therefore, in this invention, the Nb content is controlled at 3.0–3.5%.

[0032] V: V mainly plays a role in solid solution strengthening in high-temperature alloys. V can also combine with C to form carbide-strengthened alloys. However, when the V content exceeds 1%, it promotes the thin-film distribution of grain boundary carbides, deteriorating mechanical properties. Therefore, in this invention, the V content is controlled at 0.4–0.8%.

[0033] C: In high-temperature alloys, C not only plays a role in interstitial solid solution strengthening and grain boundary strengthening, but it can also form MC and M with elements such as Nb, Ti, W, Cr, and Mo. 23 Carbides such as C6 and M6C improve mechanical properties; however, a small amount of carbon may result in insignificant strengthening effects, while excessive carbon will form large, complex-shaped carbides that become fatigue crack initiation sites, worsening fatigue performance. Therefore, in this invention, the carbon content is controlled between 0.01% and 0.08%.

[0034] B: B is a trace element. The addition of trace amounts of B can cause it to segregate at grain boundaries, increasing grain boundary bonding and significantly improving creep resistance. However, excessive B will generate coarse, brittle borides, reducing the alloy's plasticity. Therefore, in this invention, the B content is controlled between 0.005% and 0.02%.

[0035] Y+Ti+Nb+Mo+W: To fully utilize the solid solution strengthening elements Mo and W, precipitation strengthening elements Ti and Nb, and microalloying element Y in nickel-based superalloys, the content of Y+Ti+Nb+Mo+W should be relatively high. However, the simultaneous addition of multiple strengthening elements to nickel-based superalloys will significantly expand the solidification range of the alloy, causing severe element segregation, especially for easily segregated elements Y, Ti, Nb, Mo, and W. This will reduce the quality of the alloy and even lead to metallurgical defects. Therefore, considering both the strengthening effect and the alloy quality, the content of Y+Ti+Nb+Mo+W in this invention is controlled at 13-14%.

[0036] 7%≤W+Mo≤8%, W / Mo≥0.6: W and Mo are the main solid solution strengthening elements in nickel-based superalloys, and their combined addition can achieve a more significant strengthening effect. However, both W and Mo are prone to segregation. To obtain low-segregation alloys, the content of W and Mo should not be too high. Considering all factors, 7%≤W+Mo≤8% is more reasonable. W and Mo are both TCP phase forming elements, but replacing Mo with W can effectively suppress the formation of the TCP phase. Therefore, W / Mo≥0.6 needs to be controlled.

[0037] Y / C: Y has a certain affinity for C. During solidification, a small amount of Y can enter the carbides, improving their size, morphology, and distribution, thus refining the dendrites. A low Y content leads to Y mainly agglomerating at grain boundaries, unable to enter the carbides to improve their structure. An excessive Y content may cause a large amount of Y to enter the carbides, making them skeletal and larger, failing to refine the dendrites and impairing hot workability. Therefore, considering the carbide content and other factors, in this invention, 0.2 ≤ Y / C ≤ 5.

[0038] Y / B: Although both Y and B are major grain boundary strengthening elements, their atomic radii differ significantly. Y has an atomic radius of 0.1801 nm, while B has an atomic radius of 0.117 nm. The spacing between large and small atoms at grain boundaries allows for effective grain boundary strengthening. Y can not only concentrate at grain boundaries but also at crystal defects such as dislocations, stacking faults, and vacancies; therefore, the content of Y should be higher than that of B. In this invention, 1 ≤ Y / B ≤ 15.

[0039] Preferably, the present invention provides a nickel-based wrought superalloy with the following chemical composition by mass percentage: Y: 0.01-0.15%, Co: 14.81-14.91%, Cr: 10.91-11.01%, W: 3.05-3.09%, Mo: 4.41-4.63%, Al: 3.7-3.81%, Ti: 2.65-2.71%, Nb: 3.14-3.27%, V: 0.58-0.62%, C: 0.034-0.035%, B: 0.005-0.01%, with the remainder being Ni and unavoidable impurities; Preferably, the mass percentage of Y+Ti+Nb+Mo+W is 13.4% to 13.57%; Preferably, 7.46%≤W+Mo%≤7.69, 0.6≤W / Mo≤0.692; Preferably, 0.294≤Y / C≤4.412.

[0040] Preferably, 1 ≤ Y / B ≤ 15.

[0041] This invention also provides a method for preparing a nickel-based wrought superalloy, which uses the composition design of the above-mentioned nickel-based wrought superalloy and includes the following steps: S1: Preparation of raw materials for smelting. According to the composition requirements of the nickel-based wrought high-temperature alloy, a certain amount of pure metal and / or alloy is weighed as raw materials. The raw materials containing Y element are wrapped with Ni foil and placed into two different feeding chambers of the vacuum induction furnace. The raw materials containing other elements are placed into the crucible of the vacuum induction furnace. The vacuum induction furnace is sealed and vacuum treatment is performed.

[0042] It should be noted that the raw materials containing Y are elemental Y and / or Ni-Y master alloys; the purity of elemental Y is ≥99.99%, and the mass fraction of Y in the Ni-Y master alloy raw materials is between 20% and 80%. To reduce the introduction of impurity O, the O content in elemental Y or Ni-Y master alloys does not exceed 80 ppm. The rare earth Y raw materials are in the form of plates, with Ni foil separating the plates and ultimately completely wrapping the outer surface of the Y raw materials with Ni foil. By layering the rare earth Y raw materials with Ni foil, the plate-shaped rare earth Y raw materials can be added to the alloy liquid layer by layer to contact the alloy liquid, reducing the burning loss of rare earth Y and thus improving the yield; the plate-shaped rare earth Y raw materials can increase the contact area between the raw materials and the alloy liquid, so that the rare earth Y melts uniformly in the alloy liquid, and after complete melting, it is more evenly distributed in the alloy liquid.

[0043] The raw material containing element Y was wrapped in Ni foil and then placed into two different feeding chambers of the vacuum induction furnace. The mass ratio of the raw material containing element Y in the two feeding chambers was 1:1.

[0044] Raw materials containing other elements include carbon powder or carbon blocks (C), electrolytic cobalt (Co), high-purity chromium (Cr), molybdenum bars (Mo) or nickel-molybdenum master alloy (Ni-Mo), nickel-tungsten master alloy (Ni-W), nickel-boron master alloy (Ni-B), vanadium-aluminum master alloy (V-Al), sponge titanium or titanium ingots (Ti), aluminum briquettes (Al), nickel-niobium master alloy (Ni-Nb), and electrolytic nickel or nickel beads (Ni).

[0045] The preferred material is carbon block (C), as carbon powder dissolves faster and carbon block dissolves slower, resulting in a better deoxidation effect. The preferred material is a combination of electrolytic nickel and nickel beads. Electrolytic nickel plates have a higher content of impurities such as sulfur, while nickel beads have a higher content of impurities such as oxygen. Considering factors such as cost and purity, the Ni raw material uses a combination of electrolytic nickel and nickel beads.

[0046] S2: Raw material melting: The raw materials in the crucible are heated under vacuum conditions to completely melt them into a liquid. Specifically, the vacuum degree is ≤1 Pa (exemplarily, the vacuum degree is 0.2 Pa, 0.3 Pa, 0.4 Pa, 0.5 Pa, 0.6 Pa, 0.7 Pa, 0.8 Pa, 0.9 Pa), and the complete melting temperature is 1500℃~1580℃ (exemplarily, the complete melting temperature is 1505℃, 1510℃, 1515℃, 1520℃, 1525℃, 1530℃, 1535℃, 1540℃, 1545℃).

[0047] By evacuating the vacuum to ≤1 Pa (i.e., high vacuum state), the partial pressure of gases such as H2O, H2, and N2 in the furnace cavity is greatly reduced. This can effectively prevent highly oxidizable active elements such as Al, Ti, and Y from being oxidized and forming slag during the high-temperature melting stage. If these elements are oxidized in large quantities in the early stage of melting, it will not only cause inaccurate composition control and reduced yield, but the generated oxide inclusions will also seriously deteriorate the purity and fatigue performance of the alloy.

[0048] The nickel-based superalloy of this invention contains a large number of high-melting-point elements (such as W, Mo, Nb, etc.), and its liquidus temperature is usually high. Setting the upper limit of the melting temperature at 1580°C is sufficient to ensure that all alloy raw materials (including high-melting-point metals) are completely and thoroughly melted into a homogeneous liquid phase. If the melting temperature is higher than 1580°C, the excessively high temperature will significantly aggravate the volatilization loss of certain volatile elements (such as Al, Ti, Cr, etc.), resulting in inaccurate control of the alloy composition and the formation of condensates on the inner wall of the furnace, contaminating subsequent smelting. At the same time, excessively high temperatures will aggravate the chemical reaction between the melt and the crucible, causing crucible elements (such as Mg, Ca) to dissolve into the melt, introducing new impurities and reducing the purity of the alloy. If the melting temperature is lower than 1500°C, it may result in poor melt fluidity, making it impossible to achieve effective mass and heat transfer, making it difficult to remove impurities and achieve homogeneous composition.

[0049] S3: Primary refining, which involves refining the molten alloy after the raw materials in the crucible have been completely melted. Specifically, the refining temperature is 1450℃~1530℃ (for example, the refining temperatures are 1455℃, 1460℃, 1465℃, 1470℃, 1475℃, 1480℃, 1485℃, 1490℃, 1495℃, 1500℃, 1505℃, 1510℃, 1515℃, 1520℃, and 1525℃), and the refining time is ≥10min (for example, the refining time is 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, and 50 min). The first stage of refining involves a vacuum degree ≤0.1 Pa (exemplary vacuum degrees are 0.01 Pa, 0.02 Pa, 0.03 Pa, 0.04 Pa, 0.05 Pa, 0.06 Pa, 0.07 Pa, 0.08 Pa, and 0.09 Pa) to perform high-vacuum degassing and remove as much harmful gas as possible from the molten alloy.

[0050] It should be noted that within this refining temperature range, carbon-oxygen interaction can be promoted, melt volatilization and crucible reaction can be controlled, and the good state of the melt can be maintained. A refining time of ≥10 min ensures that the gas has sufficient time to escape, allowing inclusions to float fully and ensuring uniformity of composition and temperature. The high vacuum degree (≤0.1 Pa) creates an extremely low gas partial pressure environment, providing a huge driving force for the escape of dissolved H and N in the melt, enabling them to be deeply removed. The high vacuum environment isolates the melt from air, completely eliminating the possibility of the melt absorbing gas and oxidizing from the environment during high-temperature, long-term refining, ensuring the stability of the refining effect.

[0051] S4: After the first feeding and refining, the alloy liquid is cooled down. After cooling, argon gas is introduced into the vacuum induction furnace. Then, the raw material containing Y element wrapped in Ni foil in a feeding chamber in the vacuum induction furnace is added to the alloy liquid and the crucible is shaken to carry out heat preservation and impurity removal treatment. Specifically, after one refining step, the alloy liquid is cooled to 1430–1450°C (exemplary values: 1432°C, 1434°C, 1435°C, 1436°C, 1438°C, 1440°C, 1442°C, 1444°C, 1445°C, 1446°C, 1448°C). After cooling, argon gas is introduced into the vacuum induction furnace. Under argon protection, the vacuum level is 50 ± 10 Pa (exemplary values: 40 Pa, 42 Pa, 44 Pa, 46 Pa, 48 Pa, 50 Pa, 52 Pa, 54 Pa, 56 Pa, 58 Pa, 60 Pa). Rare earth Y raw material wrapped in Ni foil in a feeding bin of a vacuum induction furnace is added to the alloy liquid and the crucible is shaken to make the inclusions float to the surface, thereby achieving heat preservation and impurity removal treatment. The heat preservation temperature is 1430~1450℃ (exemplary, 1432℃, 1434℃, 1435℃, 1436℃, 1438℃, 1440℃, 1442℃, 1444℃, 1445℃, 1446℃, 1448℃), and the heat preservation time is ≥5min (exemplary, 10min, 15min, 20min, 25min, 30min).

[0052] It should be noted that the vacuum degree under argon protection is 50±10 Pa. Due to the high reactivity of rare earth element Y, it is prone to burn-off. Therefore, argon gas needs to be introduced into the vacuum induction furnace for protection before adding the alloy liquid to the crucible. If the vacuum degree is too high, a large amount of rare earth Y will vaporize during the melting process in the alloy liquid and be extracted by the vacuum system, making it impossible to form inclusions with harmful elements such as O and S in the alloy liquid to achieve impurity removal. If the vacuum degree is too low, the pressure difference between the furnace cavity of the vacuum induction furnace and the alloy liquid will be small, so that the inclusions formed in the alloy liquid after the addition of rare earth Y cannot float to the surface and the impurity gas cannot be efficiently removed. In this invention, the vacuum degree under argon protection is 50±10 Pa, which can achieve less rare earth Y burn-off and better impurity removal effect.

[0053] S5: Secondary refining, improving the vacuum level and temperature in the vacuum induction furnace to perform secondary refining of the alloy liquid; Specifically, the alloy liquid is further refined by increasing the vacuum level and temperature in the vacuum induction furnace, and further degassing is carried out. The vacuum level is ≤1 Pa (exemplary, the vacuum level is 0.2 Pa, 0.3 Pa, 0.4 Pa, 0.5 Pa, 0.6 Pa, 0.7 Pa, 0.8 Pa, 0.9 Pa), the refining temperature is 1450℃~1500℃ (exemplary, the refining temperature is 1455℃, 1460℃, 1465℃, 1470℃, 1475℃, 1480℃, 1485℃, 1490℃, 1495℃), and the refining time is ≥10 min (exemplary, the refining time is 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min).

[0054] S6: After the second feeding and refining, the alloy liquid is cooled down. After cooling down, argon gas is introduced into the vacuum induction furnace. Then, the raw material containing Y element wrapped in Ni foil in another feeding chamber in the vacuum induction furnace is added to the alloy liquid and the alloy liquid is electromagnetically stirred at the holding temperature. Specifically, after the secondary refining, the alloy liquid is cooled to 1430–1480℃ (exemplary values: 1435℃, 1440℃, 1445℃, 1450℃, 1455℃, 1460℃, 1465℃, 1470℃, 1475℃). After cooling, argon gas is introduced into the vacuum induction furnace, and under argon protection, the vacuum degree is ≥5000Pa (exemplary values: 5100 Pa, 5200 Pa, 5300 Pa, 5400 Pa, 5500 Pa, 5600 Pa, 5700 Pa, 5800 Pa, 5900 Pa, 6000 Pa). The extremely high furnace pressure can suppress the volatilization of Y from the alloy liquid, thereby increasing the yield of Y. Subsequently, rare earth Y raw material wrapped in Ni foil in another feeding bin of the vacuum induction furnace is added to the alloy liquid, and the alloy liquid is electromagnetically stirred at the holding temperature to make the rare earth Y uniformly distributed in the alloy liquid. During this time, the holding temperature is 1430~1480℃ (exemplary, 1435℃, 1440℃, 1445℃, 1450℃, 1455℃, 1460℃, 1465℃, 1470℃, 1475℃), and the holding time is ≥5min (exemplary, 10min, 15min, 20min, 25min, 30min).

[0055] S7: Casting and unloading: The alloy liquid that has been kept at a constant temperature in step S6 is cast. After casting, it is placed in the furnace for a certain period of time to allow the alloy liquid to completely solidify before being unloaded, thus obtaining the final alloy.

[0056] Specifically, the pouring temperature is 1430–1480℃ (exemplary, 1435℃, 1440℃, 1445℃, 1450℃, 1455℃, 1460℃, 1465℃, 1470℃, 1475℃), and the furnace placement time is ≥30 min (exemplary, 35 min, 40 min, 45 min, 50 min, 55 min).

[0057] Within this pouring temperature range, sufficient fluidity of the melt is ensured during pouring. Below 1430℃, the melt fluidity is poor; above 1480℃, the melt in the mold dissipates heat slowly, resulting in slow solidification and potentially coarse alloy grains. Excessively high temperatures exacerbate the segregation of alloying elements. A pouring temperature of 1430–1480℃ accelerates the solidification rate and shortens element diffusion time, thereby mitigating dendrite segregation. A furnace placement time of ≥30 minutes ensures complete solidification and internal quality of the alloy. A longer furnace placement time after pouring is equivalent to furnace cooling; this slow cooling method minimizes the temperature difference between the inside and outside of the alloy, promotes even cooling, effectively reduces thermal stress, and prevents cold cracking. It also helps obtain a uniform and stable microstructure and prevents surface oxidation and contamination.

[0058] The nickel-based wrought superalloy prepared by the method of the present invention has a relatively uniform and fine microstructure, with a secondary dendrite spacing between 38-47 μm. The alloy microstructure contains a low content of harmful interdendritic precipitates and does not have metallurgical defects such as white spots or black spots, which meets the quality requirements of high-quality nickel-based superalloys.

[0059] This invention utilizes the low free energy of rare earth element Y (Y) in combination with impurity elements such as O and S to form high-melting-point, low-density inclusions (such as Y₂O₃ and YS) through two refining and feeding processes in nickel-based wrought superalloys. These inclusions float to the surface in the molten alloy and are removed. By controlling key smelting parameters (refining temperature and time, feeding, and vacuum), efficient removal of O, S, N, and P from rare earth Y during the metallurgical process can be achieved, resulting in a high-purity alloy. Furthermore, by controlling the segregation of easily segregating elements... By utilizing the atomic size effect and unique physicochemical properties of rare earth element Y, the Y element is segregated at the solid-liquid interface to hinder the diffusion of easily segregated elements into the liquid phase during solidification, thus reducing segregation. Simultaneously, the Y segregated at the solid-liquid interface can reduce the interfacial energy, surface tension, and critical nucleation supercooling, thereby promoting grain nucleation during solidification. Combined with a suitable pouring temperature, this accelerates melt solidification, inhibits segregation, and refines dendrites, achieving the preparation of fine-dendritic, low-segregation alloys and significantly improving the metallurgical quality of the obtained vacuum induction melting alloys. Two refining and feeding processes ensure both the removal of impurities from rare earth Y and the effective addition of rare earth Y, achieving micro-alloying of rare earth Y.

[0060] The nickel-based wrought superalloy prepared by this invention has a tensile strength ≥150MPa (e.g., 152-172MPa), a yield strength ≥105MPa (e.g., 108-122MPa), an elongation ≥5.0% (e.g., 5.2-7.2%), and a reduction of area ≥7% (e.g., 7.2-9.0%) at 1120℃.

[0061] The advantages of the present invention in precisely controlling the elemental chemical composition, content, and preparation process parameters will be demonstrated below with specific examples and comparative examples.

[0062] Example 1 This embodiment provides a nickel-based wrought superalloy with the following chemical composition by mass percentage: Y: 0.01%, Co: 14.81%, Cr: 11.01%, W: 3.05%, Mo: 4.41%, Al: 3.81%, Ti: 2.69%, Nb: 3.24%, V: 0.62%, C: 0.034%, B: 0.01%, with the remainder being Ni and unavoidable impurities; The mass percentages of Y+Ti+Nb+Mo+W are 13.40%; W+Mo is 7.46%; W / Mo is 0.692; Y / C is 0.294; and Y / B is 1.

[0063] The preparation method of the nickel-based wrought superalloy in this embodiment includes the following steps: S1: Preparation of raw materials for smelting. According to the composition requirements of the nickel-based wrought high-temperature alloy, a certain amount of pure metal and / or alloy is weighed as raw materials. The raw materials containing Y element are wrapped with Ni foil and placed into two different feeding chambers of the vacuum induction furnace. The raw materials containing other elements are placed into the crucible of the vacuum induction furnace. The vacuum induction furnace is sealed and vacuum treatment is performed.

[0064] Among them, the rare earth Y element raw material is elemental Y or Ni-Y master alloy; the purity of elemental Y is ≥99.99%, the mass fraction of Y in the Ni-Y master alloy raw material is between 20% and 80%; the O content in elemental Y or Ni-Y master alloy does not exceed 80ppm.

[0065] The raw material of element Y was wrapped with Ni foil and then placed into two different feeding bins of a vacuum induction furnace. The mass ratio of rare earth Y raw material in the two feeding bins was 1:1.

[0066] Raw materials containing other elements include carbon powder or carbon blocks (C), electrolytic cobalt (Co), high-purity chromium (Cr), molybdenum bars (Mo) or nickel-molybdenum master alloy (Ni-Mo), nickel-tungsten master alloy (Ni-W), nickel-boron master alloy (Ni-B), vanadium-aluminum master alloy (V-Al), sponge titanium or titanium ingots (Ti), aluminum briquettes (Al), nickel-niobium master alloy (Ni-Nb), and electrolytic nickel or nickel beads (Ni).

[0067] S2: Raw material melting: The raw materials in the crucible are heated under vacuum conditions to completely melt them into a liquid. Specifically, the vacuum degree is 0.1 Pa, and the complete melting temperature is 1550°C.

[0068] S3: Primary refining, which involves refining the molten alloy after the raw materials in the crucible have been completely melted. Specifically, the refining temperature is 1530℃ and the refining time is 10 minutes. The first stage of refining is carried out under a high vacuum of 0.1 Pa to remove harmful gases from the molten alloy as much as possible.

[0069] S4: After the first feeding and refining, the alloy liquid is cooled down. After cooling, argon gas is introduced into the vacuum induction furnace. Then, the raw material containing Y element wrapped in Ni foil in a feeding chamber in the vacuum induction furnace is added to the alloy liquid and the crucible is shaken to carry out heat preservation and impurity removal treatment. After one refining process, the alloy liquid is cooled to 1450℃. After cooling, argon gas is introduced into the vacuum induction furnace. Under argon protection, the vacuum degree is 50Pa. Rare earth Y raw material wrapped in Ni foil in a feeding bin of the vacuum induction furnace is added to the alloy liquid, and the crucible is shaken to make the inclusions float to the surface, thus achieving heat preservation and impurity removal treatment. The heat preservation temperature is 1450℃ and the heat preservation time is 5min.

[0070] S5: Secondary refining, improving the vacuum level and temperature in the vacuum induction furnace to perform secondary refining of the alloy liquid; The process involves increasing the vacuum level and temperature in the vacuum induction furnace to perform secondary refining of the alloy liquid and further degassing. The vacuum level is 1 Pa, the refining temperature is 1500℃, and the refining time is 10 min.

[0071] S6: After the second feeding and refining, the alloy liquid is cooled down. After cooling down, argon gas is introduced into the vacuum induction furnace. Then, the raw material containing Y element wrapped in Ni foil in another feeding chamber in the vacuum induction furnace is added to the alloy liquid and the alloy liquid is electromagnetically stirred at the holding temperature. After the secondary refining, the alloy liquid is cooled to 1460℃. After cooling, argon gas is introduced into the vacuum induction furnace, and the vacuum degree is 5000Pa under argon protection. Then, rare earth Y raw material wrapped in Ni foil in another feeding chamber of the vacuum induction furnace is added to the alloy liquid, and the alloy liquid is electromagnetically stirred at the holding temperature to make the rare earth Y evenly distributed in the alloy liquid. During this time, the holding temperature is 1460℃ and the holding time is 5min.

[0072] S7: Casting and unloading: The alloy liquid that has been kept at a constant temperature in step S6 is cast. After casting, it is placed in the furnace for a certain period of time to allow the alloy liquid to completely solidify before being unloaded, thus obtaining the final alloy.

[0073] Specifically, the pouring temperature is 1460℃, and the placement time in the furnace is 30 minutes.

[0074] Example 2 This embodiment provides a nickel-based wrought superalloy with the following chemical composition by mass percentage: Y: 0.015%, Co: 14.91%, Cr: 11%, W: 3.05%, Mo: 4.48%, Al: 3.81%, Ti: 2.71%, Nb: 3.27%, V: 0.62%, C: 0.034%, B: 0.01%, with the remainder being Ni and unavoidable impurities; The mass percentages of Y+Ti+Nb+Mo+W are 13.53%; W+Mo is 7.53%; W / Mo is 0.681; Y / C is 0.441; and Y / B is 1.5.

[0075] The preparation method of the nickel-based wrought superalloy in this embodiment is the same as that in Example 1.

[0076] Example 3 This embodiment provides a nickel-based wrought superalloy with the following chemical composition by mass percentage: Y: 0.05%, Co: 14.91%, Cr: 10.95%, W: 3.09%, Mo: 4.59%, Al: 3.7%, Ti: 2.66%, Nb: 3.14%, V: 0.59%, C: 0.035%, B: 0.01%, with the remainder being Ni and unavoidable impurities; The mass percentages of Y+Ti+Nb+Mo+W are 13.53%; W+Mo is 7.68%; W / Mo is 0.673; Y / C is 1.429; and Y / B is 5.

[0077] The preparation method of the nickel-based wrought superalloy in this embodiment is the same as that in Example 1.

[0078] Example 4 This embodiment provides a nickel-based wrought superalloy with the following chemical composition by mass percentage: Y: 0.07%, Co: 14.85%, Cr: 10.92%, W: 3.06%, Mo: 4.63%, Al: 3.75%, Ti: 2.65%, Nb: 3.16%, V: 0.58%, C: 0.034%, B: 0.01%, with the remainder being Ni and unavoidable impurities; The mass percentages of Y+Ti+Nb+Mo+W are 13.57%; W+Mo is 7.69%; W / Mo is 0.661; Y / C is 2.059; and Y / B is 7.

[0079] The preparation method of the nickel-based wrought superalloy in this embodiment is the same as that in Example 1.

[0080] Example 5 This embodiment provides a nickel-based wrought superalloy with the following chemical composition by mass percentage: Y: 0.1%, Co: 14.9%, Cr: 10.94%, W: 3.06%, Mo: 4.57%, Al: 3.70%, Ti: 2.65%, Nb: 3.14%, V: 0.59%, C: 0.035%, B: 0.01%, with the remainder being Ni and unavoidable impurities; The mass percentages of Y+Ti+Nb+Mo+W are 13.52%; W+Mo is 7.63%; W / Mo is 0.67; Y / C is 2.857; and Y / B is 10.

[0081] The preparation method of the nickel-based wrought superalloy in this embodiment is the same as that in Example 1.

[0082] Example 6 This embodiment provides a nickel-based wrought superalloy with the following chemical composition by mass percentage: Y: 0.15%, Co: 14.91%, Cr: 10.91%, W: 3.07%, Mo: 4.59%, Al: 3.72%, Ti: 2.67%, Nb: 3.15%, V: 0.6%, C: 0.034%, B: 0.01%, with the remainder being Ni and unavoidable impurities; The mass percentages of Y+Ti+Nb+Mo+W are 13.63%; W+Mo is 7.66%; W / Mo is 0.669; Y / C is 4.412; and Y / B is 15.

[0083] The preparation method of the nickel-based wrought superalloy in this embodiment is the same as that in Example 1.

[0084] Example 7 This embodiment provides a nickel-based wrought superalloy with the same chemical composition as in Example 3.

[0085] The preparation method of the nickel-based wrought superalloy in this embodiment is similar to that in Example 3, except that: In S3, the refining temperature is 1500℃ and the refining time is 15min; In S5, the refining temperature is 1480℃ and the refining time is 15min; In S6, the cooling temperature is 1450℃, the vacuum degree is 6000Pa, the holding temperature is 1450℃, and the holding time is 7min.

[0086] In S7, the pouring temperature is 1450℃.

[0087] Comparative Example 1 This comparative example provides a nickel-based wrought superalloy with the following chemical composition by mass percentage: Co: 14.96%, Cr: 10.97%, W: 3.06%, Mo: 4.57%, Al: 3.75%, Ti: 2.68%, Nb: 3.14%, V: 0.6%, C: 0.035%, B: 0.01%, with the remainder being Ni and unavoidable impurities; The mass percentage of Ti+Nb+Mo+W is 13.45%; W+Mo is 7.63%; and the W / Mo ratio is 0.669.

[0088] The preparation method of a nickel-based wrought superalloy in this comparative example includes the following steps: S1: Preparation of raw materials for smelting: Weigh the corresponding raw materials of Ni, Co, Cr, W, Mo, Al, Ti, Nb, V, C and B elements according to the element ratio principle of the nickel-based wrought high-temperature alloy, put the raw materials of the elements into the crucible of the vacuum induction furnace, seal the vacuum induction furnace and perform vacuum treatment.

[0089] S2: Raw material melting: The raw materials in the crucible are heated under vacuum conditions to completely melt them into a liquid. The vacuum level is 0.1 Pa, and the complete melting temperature is 1550 °C.

[0090] S3: Refining: Refining the molten alloy in the crucible after the raw materials have been completely melted; The refining temperature is 1530℃, the refining time is 15min, and the vacuum degree is 0.1Pa to carry out high vacuum degassing to remove as much harmful gas as possible from the alloy liquid.

[0091] S4: Casting and unloading: The refined alloy liquid is cast, and after casting, it is placed in the furnace for a certain period of time to allow the alloy liquid to completely solidify before being unloaded to finally obtain the alloy. The pouring temperature range is 1460℃, and the furnace placement time is 30 minutes.

[0092] Comparative Example 2 This comparative example provides a nickel-based wrought superalloy with the following chemical composition by mass percentage: Y: 0.2%, Co: 14.9%, Cr: 10.94%, W: 3.07%, Mo: 4.59%, Al: 3.72%, Ti: 2.67%, Nb: 3.12%, V: 0.59%, C: 0.034%, B: 0.01%, with the remainder being Ni and unavoidable impurities; The mass percentages of Y+Ti+Nb+Mo+W are 13.65%; W+Mo is 7.66%; W / Mo is 0.669; Y / C is 5.882; and Y / B is 20.

[0093] The preparation method of the nickel-based wrought superalloy in this comparative example is the same as that in Example 1.

[0094] Comparative Example 3 This comparative example provides a nickel-based wrought superalloy with the same chemical composition as Example 4.

[0095] The preparation method of this comparative example of a nickel-based wrought superalloy is similar to that of Example 4, except that: S3: Refining, which involves refining the molten alloy after the raw materials in the crucible have been completely melted; Specifically, the refining temperature is 1530℃, and the refining time is 15 minutes. The vacuum degree is 0.1 Pa, and high-vacuum degassing is performed to remove as many harmful gases as possible from the alloy liquid.

[0096] S4: After the refining is completed, the alloy liquid is cooled down. After cooling down, argon gas is introduced into the vacuum induction furnace. Then, the raw material containing Y element wrapped in Ni foil in the feeding chamber of the vacuum induction furnace is added to the alloy liquid and the crucible is shaken to carry out heat preservation and impurity removal treatment. After refining, the alloy liquid is cooled to 1490℃. After cooling, argon gas is introduced into the vacuum induction furnace. Under argon protection, the vacuum degree is 3000Pa. All the rare earth Y raw materials wrapped in Ni foil in the feeding bin of the vacuum induction furnace are added into the alloy liquid and the crucible is shaken to make the inclusions float to the surface, thus achieving heat preservation and impurity removal treatment. The heat preservation temperature is 1490℃ and the heat preservation time is 5 minutes.

[0097] S5: Casting and unloading from the furnace. The alloy liquid that has been kept at a constant temperature in step S4 is cast. After casting, it is placed in the furnace for a certain period of time to allow the alloy liquid to completely solidify before being unloaded from the furnace, thus obtaining the final alloy.

[0098] Specifically, the pouring temperature is 1490℃, and the furnace placement time is 30 minutes.

[0099] Comparative Example 4 This comparative example provides a nickel-based wrought superalloy with the same chemical composition as Example 3.

[0100] The preparation method of this comparative example of a nickel-based wrought superalloy is similar to that of Example 3, except that: In step S4, the vacuum level is 500 Pa under argon protection. In step S6, the vacuum level is 3000 Pa under argon protection.

[0101] Table 1 shows the chemical composition of the alloys in the examples and comparative examples; Table 2 shows the test results for the impurity element content in the alloys in the examples and comparative examples; Table 3 shows the secondary dendrite spacing and segregation coefficients of Ti, Nb, Mo, and W in the alloys in the examples and comparative examples; Table 4 shows the tensile properties of the alloys in the examples and comparative examples at 1120℃.

[0102] Table 1 shows the chemical composition (wt, %) of the alloys in the examples and comparative examples.

[0103] Table 2. Test table of impurity element content in alloys of the examples and comparative examples.

[0104] Table 3. Secondary dendrite spacing and segregation coefficients of some elements in the alloys of the examples and comparative examples.

[0105] Table 4 Tensile properties at 1120°C for the alloys of the examples and comparative examples

[0106] The O, N, S, and P impurity element contents of the alloys from Examples 1-7 and Comparative Examples 1-4, obtained through vacuum induction melting, were tested, and the results are shown in Table 2. Dendritic structures were observed at half the radius of the alloys from Examples 1-7 and Comparative Examples 1-4, and the results are as follows: Figures 1-11 As shown in Table 3, the secondary dendrite spacing and segregation coefficients of Ti, Nb, Mo, and W elements were tested in Examples 1-7 and Comparative Examples 1-4.

[0107] As shown in Table 2, the contents of impurity elements O, N, S, and P in the alloys prepared in Examples 1-7 are all lower than those in Comparative Examples 1-4. This indicates that the trace amount of rare earth element Y (0.005-0.15%) plays a significant role in purifying the alloy. In Comparative Example 2, when the Y content is 0.2%, the addition of more rare earth element Y will weaken the purification effect and even lead to contamination of the alloy liquid. This is related to the fact that the addition of excessive reactive element Y enhances the reaction between the alloy liquid and the crucible during the smelting process. Compared with Comparative Example 3, Example 4 also added 0.07% Y, but the impurity content in the alloy prepared in Example 4 is significantly lower than that in Comparative Example 3. This shows that the alloy preparation method proposed in this invention can better exert the purification effect of rare earth Y. Although the chemical composition of Comparative Example 4 is the same as that of Example 3, some process parameters in the preparation process did not meet the requirements, resulting in a higher content of impurity elements in its alloy than that in Example 3.

[0108] From Table 3 and Figure 1-11 It can be seen that the secondary dendrite spacing of the alloys prepared in Examples 1-7 and Comparative Example 3 is smaller than that in Comparative Example 1-2, and the dendrites are significantly refined. Table 3 also shows that the segregation coefficients of easily segregating elements Ti, Nb, Mo, and W in the alloys prepared in Examples 1-7 are closer to 1 than those in Comparative Example 1-2, reducing elemental segregation and improving the compositional uniformity of the alloys. Example 4, compared to Comparative Example 3, also added 0.07% Y, and the segregation coefficients of easily segregating elements Ti, Nb, Mo, and W in the alloy prepared in Example 4 are closer to 1 than those in Comparative Example 3. This indicates that the alloy preparation method proposed in this invention can better utilize the anti-segregation effect of rare earth Y and the synergistic effect between elements. Compared to Example 3, Comparative Example 4, due to some parameters not meeting the requirements of this invention during preparation, has segregation coefficients of Ti, Nb, Mo, and W that are further away from 1 than those in Example 3. Table 4 shows that the tensile properties of the alloys in the examples at 1120℃ are all higher than those in the comparative examples.

[0109] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A nickel-based wrought superalloy, characterized in that, The chemical composition by mass percentage is as follows: Y: 0.005–0.15%, Co: 14.0–16.0%, Cr: 10–12%, W: 2.5–3.5%, Mo: 4.0–5.0%, Al: 3.5–4.0%, Ti: 2.5–3.1%, Nb: 3.0–3.5%, V: 0.4–0.8%, C: 0.01–0.08%, B: 0.005–0.02%, with the remainder being Ni and unavoidable impurities; The mass percentage of Y+Ti+Nb+Mo+W is 13-14%; The contents of W and Mo satisfy the following conditions: 7% ≤ W + Mo ≤ 8%, W / Mo ≥ 0.6; The contents of Y and C satisfy the following condition: 0.2 ≤ Y / C ≤ 5; The contents of Y and B satisfy the following condition: 1 ≤ Y / B ≤ 15; The secondary dendrite spacing in the microstructure of the nickel-based wrought superalloy is 38-47 μm; The nickel-based wrought superalloy has a tensile strength ≥150MPa, a yield strength ≥105MPa, an elongation ≥5.0%, and a reduction of area ≥7% at 1120℃.

2. A method for preparing a nickel-based wrought superalloy, comprising the compositional design of the nickel-based wrought superalloy as described in claim 1, characterized in that, The preparation method includes the following steps: S1: Preparation of raw materials for smelting. According to the composition requirements of the nickel-based wrought high-temperature alloy, a certain amount of pure metal and / or alloy is weighed as raw materials. The raw materials containing Y element are wrapped with Ni foil and placed into two different feeding chambers of the vacuum induction furnace. The raw materials containing other elements are placed into the crucible of the vacuum induction furnace. The vacuum induction furnace is sealed and vacuum treatment is performed. S2: Raw material melting: The raw materials in the crucible are heated under vacuum conditions to completely melt them into a liquid. S3: Primary refining, which involves refining the molten alloy after the raw materials in the crucible have been completely melted. S4: After the first feeding and refining, the alloy liquid is cooled down. After cooling, argon gas is introduced into the vacuum induction furnace. Then, the raw material containing Y element wrapped in Ni foil in a feeding chamber in the vacuum induction furnace is added to the alloy liquid and the crucible is shaken to carry out heat preservation and impurity removal treatment. S5: Secondary refining, improving the vacuum level and temperature in the vacuum induction furnace to perform secondary refining of the alloy liquid; S6: After the second feeding and refining, the alloy liquid is cooled down. After cooling down, argon gas is introduced into the vacuum induction furnace. Then, the raw material containing Y element wrapped in Ni foil in another feeding chamber in the vacuum induction furnace is added to the alloy liquid and the alloy liquid is electromagnetically stirred at the holding temperature. S7: Casting and unloading: The alloy liquid that has been kept at a constant temperature in step S6 is cast. After casting, it is placed in the furnace for a certain period of time to allow the alloy liquid to completely solidify before being unloaded, thus obtaining the final alloy.

3. The preparation method according to claim 2, characterized in that, In step S1, the raw material containing Y element is elemental Y and / or Ni-Y master alloy; Among them, the purity of elemental Y is ≥99.99%, and the mass fraction of Y in the Ni-Y master alloy raw material is 20%-80%; The oxygen content in elemental Y or Ni-Y master alloys shall not exceed 80 ppm; The mass ratio of the raw materials containing Y element in the two feeding bins is 1:

1.

4. The preparation method according to claim 2, characterized in that, In step S2, the vacuum degree under the vacuum conditions is ≤1 Pa, and the temperature for complete melting is 1500℃~1580℃.

5. The preparation method according to claim 2, characterized in that, In step S3, the primary refining temperature is 1450℃~1530℃, the primary refining time is ≥10min, and the primary refining vacuum degree is ≤0.1Pa.

6. The preparation method according to claim 2, characterized in that, In step S4, the heat preservation temperature is 1430~1450℃, and the heat preservation time is ≥5min.

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