A high gamma-prime content nickel-based superalloy with excellent high-temperature performance and a preparation method thereof

Abstract

This invention provides a high-γ' content nickel-based superalloy with excellent high-temperature performance and its preparation method. The compositional mass ratio of the high-γ' content nickel-based superalloy is as follows: Al+Ti: 6.0-10.0%; W+Mo: 7.0-13.0%; Ta+Hf: 0.2-4.0%; C+B+Zr: 0.05-0.2%; Nb: 0-4.5%; Co: 4.0-18.0%; Cr: 3.0-15.0%; Fe: 0-3.0%; V: 0-3.0%; Ce+Mg+Mn+Si not exceeding 0.2%, with the balance being Ni. This invention designs a nickel-based wrought superalloy with a γ' phase content exceeding 70% through composition optimization design. Subsequently, it undergoes electron beam refining, homogenization heat treatment, hot extrusion blanking, and heat treatment control, ultimately exhibiting superior mechanical properties. The yield strength of the alloy is not less than 1000 MPa at room temperature, not less than 950 MPa at 750°C, not less than 900 MPa at 850°C, not less than 530 MPa at 1000°C, not less than 220 MPa at 1150°C, and not less than 150 MPa at 1200°C.

Description

Technical Field

[0001] This invention relates to a high-γ' content nickel-based superalloy with excellent high-temperature performance and its preparation method. Background Technology

[0002] High-temperature alloys are widely used in various high-temperature structural components in the aerospace field due to their excellent high-temperature strength, structural stability, creep resistance, fatigue resistance, and corrosion resistance. In recent years, with the development of the aerospace field, there are higher demands for the service performance and high-temperature strength of materials. To meet these demands, the current development of high-temperature alloys mainly focuses on increasing the degree of alloying and the volume fraction of the γ' phase. In recent years, researchers have designed various high-performance high-temperature alloys using composition optimization design methods, such as the GH4068 alloy, which has a γ' phase content of 45% and a 1000℃ / δ... b Approximately 300 MPa; GH4151 alloy, in which the γ' phase content is 52%, 1000℃ / δ b Approximately 400 MPa; GH4975 alloy, in which the γ' phase content is 64%, 1000℃ / δ b The pressure is approximately 500 MPa. However, the large addition of alloying elements leads to severe solidification segregation, coarse as-cast microstructure, and ingot cracking. Due to the limitations of current preparation techniques, these problems have not yet been effectively solved, thus researchers have stopped at designing compositions for higher-performance high-temperature alloys. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a high-γ' content nickel-based superalloy with excellent high-temperature performance and its preparation method. Starting from the aspect of compositional optimization design, this invention successfully designs a nickel-based superalloy with a room temperature yield strength of not less than 1000 MPa, a yield strength of not less than 940 MPa at 750°C, a yield strength of not less than 900 MPa at 850°C, a yield strength of not less than 530 MPa at 1000°C, a yield strength of not less than 220 MPa at 1150°C, and a yield strength of not less than 150 MPa at 1200°C by significantly increasing the γ' phase content (γ' > 70%), maximizing the solid solution strength of the matrix, and controlling the content and distribution of carbides.

[0004] The technical means employed in this invention are as follows:

[0005] A high-γ' content nickel-based superalloy with excellent high-temperature performance, the composition by mass ratio (wt.%) is as follows:

[0006] Al+Ti: 6.0–10.0%; W+Mo: 7.0–13.0%; Ta+Hf: 0.2–4.0%; C+B+Zr: 0.05–0.2%; Nb: 0–4.5%; Co: 4.0–18.0%; Cr: 3.0–15.0%; Fe: 0–3.0%; V: 0–3.0%; Ce+Mg+Mn+Si not exceeding 0.2%, balance Ni.

[0007] Furthermore, at room temperature, the yield strength of the high γ' content nickel-based superalloy is not less than 1000 MPa; at 750°C, the yield strength is not less than 940 MPa; at 850°C, the yield strength is not less than 900 MPa; at 1000°C, the yield strength is not less than 530 MPa; at 1150°C, the yield strength is not less than 220 MPa; and at 1200°C, the yield strength is not less than 150 MPa.

[0008] The high γ' content nickel-based superalloy has a γ' phase volume fraction of over 70%.

[0009] This invention also provides a method for preparing a high-γ' content nickel-based superalloy with excellent high-temperature performance, comprising the following steps:

[0010] S1. Pretreatment of raw materials:

[0011] S11. All raw materials are made of blocky, granular or filamentous elemental metals.

[0012] S12. According to the mass ratio of the alloy components, use an electronic balance with an accuracy of 0.1g to prepare the ingredients;

[0013] S13. Place the alumina crucible in a drying oven for drying, and then put the prepared raw materials into the alumina crucible.

[0014] S2, Vacuum Induction Melting:

[0015] S21. After cleaning the inside of the induction melting furnace, turn on the cooling water and check whether the water cooling devices in each part of the induction melting furnace are leaking.

[0016] S22. Turn on the cooling water switch, air compressor, and main power supply of the induction melting equipment to begin evacuating the melting chamber until the vacuum level reaches 5×10⁻⁶. -2 After Pa, smelting begins;

[0017] S23. During the smelting process, turn on the coil heating power supply to completely melt the raw material in the alumina crucible. Then, maintain the temperature at this heating power for 30 minutes to refine the melted raw material. After refining, slowly reduce the power until the power drops to 0.

[0018] S24. Then wait for 1 hour to cool down. When the temperature of the raw material in the alumina crucible drops below 200°C, release the gas. After the vacuum in the furnace returns to atmospheric pressure, open the furnace door and take out the ingot from the alumina crucible.

[0019] S3. Preparation for pretreatment and electron beam refining of raw materials:

[0020] S31. The ingot obtained by vacuum induction melting is used as the raw material for electron beam refining, and the ingot raw material is pretreated.

[0021] S32. Select a bottomless water-cooled copper crucible, place the pretreated ingot raw material at the bottom of the cold copper crucible, and fix the ingot raw material on the ingot pulling mechanism.

[0022] S33. Then, a polished bar is tied to the feeding mechanism. By controlling the feeding mechanism, the bar can be moved horizontally above the water-cooled copper crucible.

[0023] S4, Electron Beam Refining:

[0024] Start the equipment and evacuate the furnace body and electron gun body to the target vacuum state. Then start the electron gun to preheat the equipment. After preheating, use one electron gun to melt the ingot with electron beam to form a molten pool. Use the other electron gun to melt the bar material to form droplets, which fall into the molten pool of the water-cooled copper crucible. After melting, the ingot is obtained.

[0025] S5. The ingot obtained after electron beam refining is subjected to homogenization heat treatment.

[0026] S6. High-temperature hot extrusion: Hot extrusion is used to open the billet of the homogenized heat-treated ingot; high-temperature hot extrusion yields bar ingots.

[0027] S7. Heat treatment and microstructure control: The extruded bar ingots are heat treated to obtain a high-γ' content nickel-based superalloy with excellent high-temperature performance.

[0028] Further, in step S11, the purity requirements for the raw materials are as follows: Ni purity not less than 99.96%; Co purity not less than 99%; Cr purity not less than 99.3%; W purity not less than 99.8%; Mo purity not less than 99.8%; Al purity not less than 99.8%; Ti purity not less than 99.6%; Ta purity not less than 99.5%; Hf purity not less than 99.6%; C is high-purity graphite with a purity not less than 99.5%; B purity not less than 98%; Zr purity not less than 99%; Fe purity not less than 99%; V purity not less than 98%; and Nb purity not less than 99.6%.

[0029] Furthermore, in step S13, the prepared raw materials are placed into the alumina crucible in order of their volatility, with the more volatile elements placed at the bottom of the alumina crucible and the less volatile elements placed at the top. That is, the raw materials are placed into the alumina crucible from bottom to top in order of their volatility from most volatile to least volatile.

[0030] Furthermore, in step S23, the raw material in the alumina crucible is completely melted by slowly increasing the power and maintaining the temperature using a coil heating power supply. The slow power increase and temperature maintenance methods are: 3kW for 2 minutes, 5kW for 2 minutes, 10kW for 5 minutes, and 15kW for 5 minutes. During the melting process, the state of the raw material in the alumina crucible is observed at any time through an observation window.

[0031] Furthermore, the pretreatment of the ingot raw material in step S31 specifically includes the following steps:

[0032] S311. First, use a grinding wheel to grind away the oxide scale and impurities on the surface of the ingot raw material;

[0033] S312. Wipe the polished ingot raw material repeatedly with deionized water and alcohol to ensure that there is no oxide scale or impurities on the surface; use a blower to dry the surface moisture of the ingot raw material to ensure that the furnace charge is dry.

[0034] Furthermore, in step S32, the ingot material filling the bottom of the water-cooled copper crucible is a cylindrical ingot with a diameter 2-5 mm smaller than the inner diameter of the water-cooled copper crucible and a height of more than 150 mm. One end of the cylindrical ingot serves as the bottom of the water-cooled copper crucible, and the other end is fixed to a pulling mechanism with a rotating function. By adjusting the pulling mechanism, the cylindrical ingot can move up and down inside the water-cooled copper crucible and also has a rotating function.

[0035] Furthermore, the specific steps of step S4 are as follows:

[0036] S41. After the equipment is turned on, the vacuum level of the furnace body and electron gun body is evacuated to 5×10 using the vacuum pump unit.-3 Below Pa, the electron gun is then started for preheating: the beam current is slowly adjusted to 120mA and preheated for 10-15 minutes; after preheating, electron beam melting is carried out.

[0037] S42. First, start the right electron gun on the upper part of the water-cooled copper crucible, turn on the high voltage of the right electron gun, increase the voltage to 30kV, set the electron beam power to 10-25kW, and gradually expand the electron beam scanning radius from the center of the ingot to slowly melt the ingot.

[0038] S43. After a stable molten pool is formed, set the electron beam scanning path at 1 / 2 radius, and simultaneously turn on the spinning function, select a speed of 0.1-2 revolutions / min, and maintain it.

[0039] S44. Move the bar to the edge of the molten pool, turn on the left electron gun at the top of the feeding end, set the electron beam power to 8-15kW, set the scanning path on the bar, slowly melt the bar to form droplets, and the molten bar will drip into the water-cooled copper crucible under the action of gravity.

[0040] S45. Start the feeding mechanism and move it forward slowly. Set the feeding rate to 10-50 mm / min according to the size of the bar stock to ensure that the bar stock is fully melted and the droplets continuously and stably drip into the molten pool; after the melting is completed, an ingot is obtained.

[0041] Furthermore, in step S5, the homogenization heat treatment temperature is not lower than 1050℃, and the heat treatment is maintained for at least 20 hours.

[0042] In step S6, the ingot after homogenization heat treatment is peeled and wrapped before hot extrusion; the hot extrusion temperature is above 1100℃, the extrusion ratio is greater than 3.5, and the extrusion speed is controlled above 320mm / s.

[0043] In step S7, the heat treatment includes solution treatment and aging treatment. The solution treatment process is as follows: the solution temperature is not lower than 1100℃, the holding time is not lower than 2h, and the air is cooled. The aging treatment process is as follows: the aging temperature is not lower than 850℃, the holding time is more than 8h, and the air is cooled.

[0044] Compared with the prior art, the present invention has the following advantages:

[0045] This invention designs a nickel-based wrought superalloy with a γ' phase content exceeding 70% through compositional optimization. Following electron beam refining, homogenization heat treatment, hot extrusion, and controlled heat treatment, the alloy exhibits superior mechanical properties. Its yield strength is no less than 1000 MPa at room temperature, no less than 950 MPa at 750°C, no less than 900 MPa at 850°C, no less than 530 MPa at 1000°C, no less than 220 MPa at 1150°C, and no less than 150 MPa at 1200°C. These performance indicators far exceed those of existing wrought superalloys.

[0046] Based on the above reasons, this invention can be widely applied in fields such as aerospace. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of the electron beam refining equipment of the present invention.

[0049] Figure 2 The images show the microstructure after hot extrusion of the present invention, where (a) is the grain structure after extrusion, (b) is the low-magnification microstructure after extrusion, and (c) is the high-magnification microstructure after extrusion.

[0050] Figure 3 The images show the microstructure after heat treatment according to the present invention, wherein (a) shows the grain structure morphology after heat treatment, (b) shows the grain boundary morphology after heat treatment, and (c) shows the intragranular precipitates.

[0051] Figure 4 This is a schematic diagram of the room temperature and high temperature tensile and compressive properties of the present invention.

[0052] In the diagram: 1. Electron gun; 2. Diffusion pump; 3. Pneumatic valve; 4. Mechanical pump; 5. Electron beam; 6. Feeding mechanism; 7. Cooling water; 8. Water-cooled copper crucible; 9. Pulling mechanism; 10. Alloy melt; 11. Roots pump. Detailed Implementation

[0053] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0056] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0057] This invention provides a high-performance nickel-based superalloy that can be both 3D printed and deformable. The performance indicators of the high-performance nickel-based superalloy are as follows: yield strength at room temperature not less than 1000 MPa, yield strength at 750℃ not less than 940 MPa, yield strength at 850℃ not less than 900 MPa, yield strength at 1000℃ not less than 530 MPa, yield strength at 1150℃ not less than 220 MPa, and yield strength at 1200℃ not less than 150 MPa. The nickel-based superalloy is named GH4985, and its composition (wt.%) is as follows: Al+Ti: 6.0–10.0%; W+Mo: 7.0–13.0%; Ta+Hf: 0.2–4.0%; C+B+Zr: 0.05–0.2%; Nb: 0–4.5%; Co: 4.0–18.0%; Cr: 3.0–15.0%; Fe: 0–3.0%; V: 0–3.0%; Ce+Mg+Mn+Si not exceeding 0.2%, with the balance being Ni. This alloy not only possesses excellent high-temperature strength, but also features a γ' phase volume fraction exceeding 70%, far surpassing current 3D or wrought superalloys.

[0058] This invention also provides a method for preparing a high-γ' content nickel-based superalloy with excellent high-temperature performance, comprising the following steps:

[0059] I. Pretreatment of raw materials

[0060] 1. All raw materials shall be in the form of blocky, granular, or filamentous elemental metals. Specific requirements are as follows: Ni purity not less than 99.96%; Co purity not less than 99%; Cr purity not less than 99.3%; W purity not less than 99.8%; Mo purity not less than 99.8%; Al purity not less than 99.8%; Ti purity not less than 99.6%; Ta purity not less than 99.5%; Hf purity not less than 99.6%; C shall be high-purity graphite with a purity not less than 99.5%; B purity not less than 98%; Zr purity not less than 99%; Fe purity not less than 99%; V purity not less than 98%; Nb purity not less than 99.6%.

[0061] 2. The ingredients are prepared using an electronic balance with an accuracy of 0.1g, according to the mass ratio (wt%) of the alloy components.

[0062] 3. First, dry the alumina crucible in a drying oven. Then, add the prepared raw materials to the alumina crucible in order of their volatility. Place easily volatile elements at the bottom of the crucible and less volatile elements at the top, that is, place them in the alumina crucible from bottom to top in order of increasing volatility. Specifically, arranging the alloying elements according to their volatility characteristics can reduce the loss of easily volatile elements. If easily volatile elements are placed at the top or bottom of the alumina crucible, their volatilization rate will differ under the same melting conditions. Therefore, to minimize the loss of easily volatile elements, they should be placed at the bottom of the crucible, while less volatile elements should be placed at the top.

[0063] II. Vacuum Induction Melting

[0064] 1. Clean the inside of the induction melting furnace, connect the cooling water, and check whether the water cooling devices in each part of the melting furnace are leaking.

[0065] 2. Turn on the cooling water switch, air compressor, and main power supply of the induction melting equipment to begin evacuating the melting chamber. Turn on the mechanical pump and molecular pump sequentially until the vacuum level reaches 5×10⁻⁶. -2 After Pa, smelting begins.

[0066] 3. During the melting process, turn on the coil heating power and slowly increase the power as follows: 3kW for 2 minutes, 5kW for 2 minutes, 10kW for 5 minutes, and 15kW for 5 minutes (i.e., first increase the heating power to 3kW, hold at 3kW for 2 minutes, then increase to 5kW, hold at 5kW for 2 minutes, then increase to 10kW, hold at 10kW for 5 minutes, and finally increase to 15kW, hold at 15kW for 5 minutes). During the melting process, continuously observe the state of the raw materials in the crucible through the observation window. Completely melt the raw materials in the crucible by slowly increasing the power and holding at that temperature. Then, hold at this power for 30 minutes to refine the materials. After refining, slowly reduce the power until it reaches zero.

[0067] 4. Then wait 1 hour for cooling. Once the temperature of the raw material in the crucible drops to below approximately 200°C, release the gas. After the vacuum inside the furnace returns to atmospheric pressure, open the furnace door and remove the ingot from the crucible.

[0068] III. Preparation for Base Material Pretreatment and Electron Beam Refining

[0069] 1. To use the ingot obtained from vacuum induction melting as raw material for electron beam refining, the oxide scale and impurities on the surface of the raw material must first be ground clean with a grinding wheel.

[0070] 2. Wipe the polished alloy repeatedly with deionized water and alcohol to ensure the surface is free of oxide scale and impurities. Use a hair dryer to dry the surface of the alloy to ensure the furnace charge is dry.

[0071] 3. For this electron beam refining process, a bottomless water-cooled copper crucible was selected. Therefore, the bottom needed to be filled with a cylindrical ingot that was 2-5mm smaller than the inner diameter of the crucible and had a height of more than 150mm. This ingot had already undergone the pretreatment in step 2 of step 3. One end of the cylindrical ingot served as the bottom of the crucible, while the other end was fixed to a rotatable ingot pulling mechanism. By adjusting this ingot pulling mechanism, the ingot could be moved up and down inside the crucible and also rotated.

[0072] 4. Then, a polished bar is mechanically tied to the feeding mechanism. By controlling the feeding mechanism, the bar can be moved horizontally directly above the crucible.

[0073] IV. Electron Beam Refining

[0074] 1. After the equipment is turned on, the vacuum pump unit will evacuate the furnace body and electron gun to a vacuum level of 5×10⁻⁶. -3 Below Pa, the electron gun is then activated for preheating: the beam current is slowly adjusted to 120mA, and preheating is performed for 10–15 minutes. After preheating, electron beam melting is carried out.

[0075] 2. First, turn on the electron gun on the right side of the upper part of the water-cooled copper crucible, turn on the high voltage of the right electron gun, increase the voltage to 30kV, set the electron beam power to 10-25kW, and gradually expand the electron beam scanning radius from the center of the ingot to slowly melt the ingot.

[0076] 3. After a stable molten pool is formed, set the electron beam scanning path at 1 / 2 radius, and simultaneously turn on the spinning function, select a speed of 0.1-2 revolutions / min, and maintain it.

[0077] 4. Move the feeding rod to the edge of the molten pool, turn on the left electron gun at the top of the feeding end, set the electron beam power to 8-15kW, set the scanning path on the rod, and slowly melt the rod to form droplets. The molten rod will drip into the water-cooled copper crucible under the action of gravity.

[0078] 5. Start the feeding mechanism and move it forward slowly. Set the feeding rate to 10-50 mm / min according to the size of the feeding bar to ensure that the feeding bar is fully melted and the droplets are continuously and stably dripped into the molten pool; after the melting is completed, an ingot is obtained.

[0079] The advantages of using the vacuum induction melting-electron beam refining method are as follows: First, the purpose of vacuum induction melting is to alloy the various elemental components, forming a solid ingot for subsequent melting. In the design of alloys, the addition of a large number of alloying elements leads to severe segregation of these elements, coarse as-cast microstructure, and large sizes of impurities or inclusions. Electron beam refining technology, with its high melt pool temperature, high vacuum level, shallow melt pool, and rapid cooling rate, effectively removes inclusions and impurities from the alloy, eliminates macroscopic segregation in the ingot, reduces microscopic segregation, and refines the as-cast microstructure. Therefore, vacuum induction melting combined with electron beam refining can produce a high-purity, highly homogeneous high-temperature alloy ingot, facilitating subsequent use or processing. Compared with the traditional vacuum induction melting + electroslag remelting + vacuum consumable triple-processing technology, this method produces alloy ingots with higher purity and better homogeneity. More importantly, the process is shorter and consumes less energy. It is worth noting that the electron beam refining in this study includes single-gun, dual-gun, or multi-gun electron beam refining. The smelting process also includes boiling, refining, casting, and lamination, all of which fall under the electron beam refining method of this invention and are within the scope of protection of this invention.

[0080] V. Homogenization Heat Treatment

[0081] The ingots obtained after electron beam refining are subjected to homogenization heat treatment to eliminate dendritic structures and segregation in the as-cast state. The homogenization heat treatment temperature is not lower than 1050℃, and the holding time is at least 20 hours.

[0082] VI. High-Temperature Hot Extrusion

[0083] In this study, hot extrusion was used to prepare the homogenized heat-treated ingots. Before hot extrusion, the homogenized heat-treated ingots needed to be peeled and clad. To ensure complete fragmentation of the as-cast structure and sufficient recrystallization, the hot extrusion temperature should be above 1100℃, the extrusion ratio should be greater than 3.5, and the extrusion speed should be controlled above 320mm / s. The high-temperature hot extrusion yielded bar ingots.

[0084] VII. Heat Treatment Microstructure Control

[0085] The heat treatment includes solution treatment and aging treatment, and the material is extruded bar ingot. The solution treatment process is as follows: the solution temperature shall not be lower than 1100℃, the holding time shall not be lower than 2 hours, and air cooling shall be performed. The aging treatment process is as follows: the aging temperature shall not be lower than 850℃, the holding time shall be higher than 8 hours, and air cooling shall be performed.

[0086] Ultimately, a nickel-based superalloy with high γ' content and excellent high-temperature performance was obtained.

[0087] like Figure 1The diagram shows a schematic of the electron beam refining equipment of the present invention. Two electron guns 1 are fixed on the top sides of the electron beam melting furnace. A water-cooled copper crucible 8 and a pulling mechanism 9 are placed inside the electron beam melting furnace. The pulling mechanism 9 is located below the water-cooled copper crucible 8, and an ingot is fixed on the pulling mechanism 9. The ingot is placed at the bottom of the water-cooled copper crucible 8, and cooling water 7 is circulated through the water-cooled copper crucible 8. A feeding mechanism 6 is placed on a bar stock and is located above the water-cooled copper crucible 8. The ingot is within the scanning range of the electron beam 5 of the right electron gun 1 and melts uniformly under the action of the electron beam 5, forming a molten pool. The bar stock is within the scanning range of the electron beam 5 of the left electron gun 1 and forms droplets under the action of the electron beam 5. These droplets fall into the water-cooled copper crucible 8 and onto the molten pool, ultimately forming an alloy melt 10. The diffusion pumps 2 on both sides above are connected to the mechanical pumps 4 through pneumatic valves 3. A diffusion pump 2, a mechanical pump 4, and a roots pump 11 are installed on the lower right side. One end of the diffusion pump 2 is connected to the electron beam melting furnace, and the other end is connected to one end of the roots pump 7. One end of the roots pump 7 is also connected to the electron beam melting furnace, and the other end is connected to the mechanical pump 4.

[0088] like Figure 2 The image shown is a microstructure diagram of the alloy after hot extrusion blanking according to the present invention. After blanking using hot extrusion technology, the coarse grains of the as-cast alloy are completely replaced by fine equiaxed grains, such as... Figure 2 As shown in (a), microscopic observation revealed the presence of multi-scale γ' phases in the alloy. Large primary γ' phases are distributed at grain boundaries; these precipitates are inherited from the homogenization or extrusion processes due to failure to re-dissolve. Fine secondary γ' phases, less than 500 nm in size, are distributed within the grains; these precipitates emerge from the matrix during cooling after extrusion.

[0089] like Figure 3 The image shown is a microstructure diagram of the alloy after heat treatment according to the present invention. After solution treatment and aging, the grain size in the alloy is approximately 100 μm. Figure 3 As shown in (a), dispersed carbide phases and MC carbides inherited from the as-cast state are distributed at the grain boundaries. The grain boundary carbides are smaller than 1 μm in size, and the MC carbides are smaller than 10 μm in size. During deformation, the presence of carbides can hinder the slip of dislocations and grain boundaries. The smaller the carbide size, the better the hindering effect.

[0090] like Figure 4 The diagram shows the room temperature and high temperature tensile and compressive properties of this invention. It is evident that the alloy exhibits excellent strength at high temperatures, far exceeding that of existing high-temperature alloys used in deformation and 3D printing.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a nickel-based superalloy with high γ' content and excellent high-temperature performance, characterized in that, The compositional mass ratio of the high-γ' content nickel-based superalloy with excellent high-temperature performance is as follows (wt.%): Al+Ti: 6.0~10.0%; W+Mo: 7.0~13.0%; Ta+Hf: 0.2~4.0%; C+B+Zr: 0.05~0.2%; Nb: 0~4.5%; Co: 4.0~18.0%; Cr：3.0~15.0%； Fe: 0~3.0%; V: 0~3.0%; Ce+Mg+Mn+Si not exceeding 0.2%, balance being Ni; At room temperature, the yield strength of the high γ' content nickel-based superalloy is not less than 1000 MPa; at 750°C, the yield strength is not less than 940 MPa; at 850°C, the yield strength is not less than 900 MPa; at 1000°C, the yield strength is not less than 530 MPa; at 1150°C, the yield strength is not less than 220 MPa; and at 1200°C, the yield strength is not less than 150 MPa. The high γ' content nickel-based superalloy has a γ' phase volume fraction of over 70%; The preparation method of the high-γ' content nickel-based superalloy with excellent high-temperature performance includes the following steps: S1. Pretreatment of raw materials: S11. All raw materials are made of blocky, granular or filamentous elemental metals. S12. According to the mass ratio of the alloy components, use an electronic balance with an accuracy of 0.1g to prepare the ingredients; S13. Place the alumina crucible in a drying oven for drying, and then put the prepared raw materials into the alumina crucible. S2, Vacuum Induction Melting: S21. After cleaning the inside of the induction melting furnace, turn on the cooling water and check whether the water cooling devices in each part of the induction melting furnace are leaking. S22. Turn on the cooling water switch, air compressor, and main power supply of the induction melting equipment to begin evacuating the melting chamber until the vacuum level reaches 5×10⁻⁶. -2 After Pa, smelting begins; S23. During the smelting process, turn on the coil heating power supply to completely melt the raw material in the alumina crucible. Then, maintain the temperature at this heating power for 30 minutes to refine the melted raw material. After refining, slowly reduce the power until the power drops to 0. S24. Then wait for 1 hour to cool down. When the temperature of the raw material in the alumina crucible drops below 200°C, release the gas. After the vacuum in the furnace returns to atmospheric pressure, open the furnace door and take out the ingot from the alumina crucible. S3. Preparation for pretreatment and electron beam refining of raw materials: S31. The ingot obtained by vacuum induction melting is used as the raw material for electron beam refining, and the ingot raw material is pretreated. S32. Select a bottomless water-cooled copper crucible, place the pretreated ingot raw material at the bottom of the cold copper crucible, and fix the ingot raw material on the ingot pulling mechanism. S33. Then, a polished bar is tied to the feeding mechanism. By controlling the feeding mechanism, the bar can be moved horizontally above the water-cooled copper crucible. S4, Electron Beam Refining: Start the equipment and evacuate the furnace body and electron gun body to the target vacuum state. Then start the electron gun to preheat the equipment. After preheating, use one electron gun to melt the ingot with electron beam to form a molten pool. Use the other electron gun to melt the bar material to form droplets, which fall into the molten pool of the water-cooled copper crucible. After melting, the ingot is obtained. S5. The ingot obtained after electron beam refining is subjected to homogenization heat treatment. S6. High-temperature hot extrusion: Hot extrusion is used to open the billet of the homogenized heat-treated ingot; high-temperature hot extrusion yields bar ingots. S7. Heat treatment and microstructure control: The extruded bar ingots are heat treated to obtain a high-γ' content nickel-based superalloy with excellent high-temperature performance.

2. The method for preparing the high-γ' content nickel-based superalloy with excellent high-temperature performance according to claim 1, characterized in that, In step S11, the purity requirements for the raw materials are as follows: Ni purity not less than 99.96%; Co purity not less than 99%; Cr purity not less than 99.3%; W purity not less than 99.8%; Mo purity not less than 99.8%; Al purity not less than 99.8%; Ti purity not less than 99.6%; Ta purity not less than 99.5%; Hf purity not less than 99.6%; C is high-purity graphite with a purity not less than 99.5%; B purity not less than 98%; Zr purity not less than 99%; Fe purity not less than 99%; V purity not less than 98%; and Nb purity not less than 99.6%.

3. The method for preparing the high-γ' content nickel-based superalloy with excellent high-temperature performance according to claim 1, characterized in that, In step S13, the prepared raw materials are placed into the alumina crucible in order of their volatility, with the more volatile elements placed at the bottom and the less volatile elements placed at the top. That is, the raw materials are placed into the alumina crucible from bottom to top in order of their volatility from most volatile to least volatile.

4. The method for preparing the high-γ' content nickel-based superalloy with excellent high-temperature performance according to claim 1, characterized in that, In step S23, the raw material in the alumina crucible is completely melted by slowly increasing the power and holding the temperature using a coil heating power supply. The slow power increase and temperature holding methods are: 3kW for 2 minutes, 5kW for 2 minutes, 10kW for 5 minutes, and 15kW for 5 minutes. During the melting process, the state of the raw material in the alumina crucible is observed at any time through an observation window.

5. The method for preparing the high-γ' content nickel-based superalloy with excellent high-temperature performance according to claim 1, characterized in that, The pretreatment of the ingot raw materials in step S31 specifically includes the following steps: S311. First, use a grinding wheel to grind away the oxide scale and impurities on the surface of the ingot raw material; S312. Wipe the polished ingot raw material repeatedly with deionized water and alcohol to ensure that there is no oxide scale or impurities on the surface; use a blower to dry the surface moisture of the ingot raw material to ensure that the furnace charge is dry.

6. The method for preparing the high-γ' content nickel-based superalloy with excellent high-temperature performance according to claim 1, characterized in that, In step S32, the ingot material filling the bottom of the water-cooled copper crucible is a cylindrical ingot with a diameter 2-5 mm smaller than the inner diameter of the water-cooled copper crucible and a height of more than 150 mm. One end of the cylindrical ingot serves as the bottom of the water-cooled copper crucible, and the other end is fixed to a pulling mechanism with a rotating function. By adjusting the pulling mechanism, the cylindrical ingot can move up and down inside the water-cooled copper crucible and also has a rotating function.

7. The method for preparing the high-γ' content nickel-based superalloy with excellent high-temperature performance according to claim 1, characterized in that, The specific steps of step S4 are as follows: S41. After the equipment is turned on, the vacuum level of the furnace body and electron gun body is evacuated to 5×10 using the vacuum pump unit. -3 Below Pa, the electron gun is then started for preheating: the beam current is slowly adjusted to 120mA and preheated for 10~15min; after preheating, electron beam melting is carried out. S42. First, start the right electron gun on the upper part of the water-cooled copper crucible, turn on the high voltage of the right electron gun, increase the voltage to 30kV, set the electron beam power to 10-25kW, and gradually expand the electron beam scanning radius from the center of the ingot to slowly melt the ingot. S43. After a stable molten pool is formed, set the electron beam scanning path at 1 / 2 radius, and simultaneously turn on the spinning function, select a speed of 0.1-2 revolutions / min, and maintain it. S44. Move the bar to the edge of the molten pool, turn on the left electron gun at the top of the feeding end, set the electron beam power to 8-15kW, set the scanning path on the bar, slowly melt the bar to form droplets, and the molten bar will drip into the water-cooled copper crucible under the action of gravity. S45. Start the feeding mechanism and move it forward slowly. Set the feeding rate to 10-50 mm / min according to the size of the bar stock to ensure that the bar stock is fully melted and the droplets continuously and stably drip into the molten pool; after the melting is completed, an ingot is obtained.

8. The method for preparing the high-γ' content nickel-based superalloy with excellent high-temperature performance according to claim 1, characterized in that, In step S5, the homogenization heat treatment temperature is not lower than 1050℃, and the heat treatment is maintained for at least 20 hours. In step S6, the ingot after homogenization heat treatment is peeled and wrapped before hot extrusion; the hot extrusion temperature is above 1100℃, the extrusion ratio is greater than 3.5, and the extrusion speed is controlled above 320mm / s. In step S7, the heat treatment includes solution treatment and aging treatment. The solution treatment process is as follows: the solution temperature is not lower than 1100℃, the holding time is not lower than 2h, and the air is cooled. The aging treatment process is as follows: the aging temperature is not lower than 850℃, the holding time is more than 8h, and the air is cooled.

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