Forming die, forming method and application of refractory high-entropy alloy gear component

Abstract

The invention discloses a forming die, a forming method and application of a refractory high-entropy alloy gear component, belongs to the technical field of near-net forming of refractory high-entropy alloy gear components, and aims to solve the technical problem that the refractory high-entropy alloy gear component is difficult to form in the prior art. The forming period of the refractory high-entropy alloy gear component is shortened, energy consumption caused by the adoption of a traditional hot forging process is reduced, the production period is shortened, the production cost is reduced, in addition, the high-temperature deformation capacity of refractory high-entropy alloy is improved through the electroplastic effect and the high-temperature softening effect, and the service life of the refractory high-entropy alloy gear component is prolonged. The limitation of ultrahigh room temperature and high-temperature strength of the refractory high-entropy alloy on forming of complex components is effectively solved, and the refractory high-entropy alloy is expected to be applied to forming of other complex components made of high-strength and difficult-to-deform materials and has wide application prospects. The manufacturing method is mainly used for manufacturing the refractory high-entropy alloy gear component.

Description

Technical Field

[0001] The present invention belongs to the technical field of near-net-shape forming of refractory high-entropy alloy gear components, and in particular relates to a forming die, a forming method and an application of a refractory high-entropy alloy gear component. Background Art

[0002] Refractory high-entropy alloys (HRAs), composed of multiple (four or more) refractory metallic elements (melting points above 1600°C), offer higher operating temperatures, high-temperature strength, and improved wear resistance, oxidation resistance, and corrosion resistance compared to traditional Ni-based superalloys. They are expected to replace Ni-based superalloys in the future as ideal high-temperature, load-bearing structural materials for advanced aerospace engines. Gear components formed from HRAs are expected to improve the service temperature and lifespan of aerospace engines and other equipment subjected to extreme conditions such as ultrahigh temperatures and ultrahigh pressures. Traditional methods for forming gears from alloys primarily include machining (e.g., hobbing, shaping, and milling), plastic forming (e.g., cold rolling, warm / hot forging, cold extrusion), and casting (e.g., pressure casting). However, HRAs typically exhibit extremely high room-temperature strength and brittleness, making them difficult to form into gears through machining and cold plastic forming. Furthermore, due to the significant differences in the melting points of their constituent elements, gears formed by casting often exhibit element segregation and coarse grains, which compromise gear performance. At high temperatures, the strength of refractory high-entropy alloys will decrease, and the plastic deformation ability will be improved. Therefore, hot forging has become the first choice for forming refractory high-entropy alloy gears. In addition, hot forging can refine the grain structure and make it uniform, which is beneficial to improving the structure and performance of the gears. However, due to the high high-temperature strength of refractory high-entropy alloys, ultra-high forming temperatures are often required. When forming gear components through traditional hot forging processes, it takes a long time to heat to reach the forming temperature, which can easily cause energy consumption and deterioration of the alloy structure. In addition, the ultra-high forming temperature poses a huge challenge to the mold material and structure, which will increase the material and processing cost of the mold. In addition, there is currently no technical disclosure on the forming method and related parameters of refractory high-entropy alloy gear components. Summary of the Invention

[0003] In order to solve the technical problem that it is difficult to form refractory high entropy alloy gear components in the prior art, the present invention provides a current-assisted forming method and application of refractory high entropy alloy gear components;

[0004] A forming die for a refractory high-entropy alloy gear component, comprising an upper die, a female die, a reinforcing sleeve, and a lower die. A blank is filled in the female die, and the upper and lower dies are relatively arranged at the upper and lower ends of the female die. The top end of the upper die is in close contact with the bottom end of an upper electrode in a spark plasma sintering furnace, the bottom end of the upper die extends into the female die and in close contact with the blank, the top end of the lower die extends to the bottom of the female die and in close contact with the blank, the bottom end of the lower die is in close contact with the top end of a lower electrode in the spark plasma sintering furnace, and the reinforcing sleeve is sleeved on the outside of the female die and radially constrains the female die.

[0005] The inner part of the die is processed with a tooth profile cavity, which is used to fill the blank during forming;

[0006] The upper die is divided into an unprocessed section and a processed section. The unprocessed section is a smooth cylinder. The cross-sectional shape of the processed section is consistent with the shape of the gear. A clearance fit is used between the processed section and the die to facilitate the longitudinal movement of the upper die during forming.

[0007] A method for forming a refractory high-entropy alloy gear component is achieved by the following steps:

[0008] Step 1: Use wire cutting technology to cut the block of refractory high entropy alloy into cylindrical billets according to the designed size;

[0009] Step 2: Surface treatment is performed on the cylindrical blank obtained after cutting in step 1;

[0010] Step 3: Place the surface-treated cylindrical blank in step 2 into a forming die, place the forming die with the cylindrical blank in a spark plasma sintering furnace, and then place the spark plasma sintering furnace in a pressure unit to form a forming device for a refractory high-entropy alloy gear component;

[0011] Step 4: After the spark plasma sintering furnace is placed in the pressure unit in step 3, the position of the forming mold is adjusted so that the infrared thermometer is aligned with the junction of the concave mold and the upper die. Subsequently, a preload of 10 MPa is applied through the pressure unit. At the same time, the upper electrode is connected to the positive pole of the pulse power supply through a wire, and the lower electrode is connected to the negative pole of the pulse power supply through a wire to ensure that the entire forming circuit is unobstructed;

[0012] Step 5: After the forming die position is adjusted in step 4 and the preload is applied, the door of the spark plasma sintering furnace is closed and the spark plasma sintering furnace is controlled to heat up. After the spark plasma sintering furnace reaches the forming temperature, the pressure unit is controlled to continuously increase the load. When the increased load reaches the target load, the temperature is maintained for a certain period of time to ensure that the cylindrical blank is completely filled in the die. Then, the heating system is turned off and the temperature in the furnace cavity is lowered to room temperature to complete the forming of the refractory high-entropy alloy gear component.

[0013] Step 6: After the temperature in the spark plasma sintering furnace in step 5 drops to room temperature, the furnace door is opened and the formed gear is taken out. Subsequently, the gear surface is polished with sandpaper to obtain the target refractory high entropy alloy gear component;

[0014] Furthermore, the composition and content of the bulk refractory high-entropy alloy in step 1 are: 18at%~22at% Hf, 18at%~22at% Mo, 18at%~22at% Nb, 18at%~22at% Ta, and 18at%~22at% Ti. The refractory high-entropy alloy has a room temperature compressive yield strength of 2325 MPa, a compressive strength of 3000 MPa, a peak stress of 140 MPa at 1200°C, and a forming temperature exceeding 1200°C.

[0015] Furthermore, in step 2, the surface treatment of the cylindrical blank obtained after cutting in step 1 is carried out in two steps. The first step is to polish with sandpaper to remove the cutting marks and oxide film on the surface of the blank. The second step is to clean the surface of the blank with alcohol and blow dry it with a hair dryer.

[0016] Furthermore, in step 4, the upper electrode and the lower electrode are both made of high-strength graphite, the compressive strength of which exceeds 50 MPa at a temperature below 1700°C;

[0017] Furthermore, in step 4, the upper die, the concave die, and the lower die are all cut from high-strength graphite rods, and the high-strength graphite rods are cut using a slow-moving precision wire cutting process with a processing accuracy of 0.005 mm.

[0018] Furthermore, after closing the door of the spark plasma sintering furnace in step 5, the vacuum system of the spark plasma sintering furnace is started to reduce the vacuum degree in the furnace chamber to 7.5×10-3Pa:

[0019] In step 5, when controlling the spark plasma sintering furnace to heat up, the temperature is heated at a heating rate of 50°C / min to 70°C / min to the desired forming temperature, which is 1400°C to 1700°C.

[0020] In step 5, when the pressure applying unit is controlled to continuously increase the load, the load is applied at a load rate of 10 MPa / min to a desired target load, which is 30 MPa to 50 MPa.

[0021] The invention discloses an application of a refractory high entropy alloy gear component, which is used as a transmission component inside an aero-engine.

[0022] The beneficial effects of this application compared to the prior art are as follows:

[0023] The present application provides a forming die, forming method and application of a refractory high entropy alloy gear component. Compared with the prior art, the present invention uses a current-assisted forming method to manufacture a refractory high entropy alloy gear component with a pitch circle diameter of 2mm~40mm and a tooth surface roughness of Ra0.2~Ra0.8. Compared with traditional processing and manufacturing technologies, the current-assisted forming method of the present invention has an extremely high heating rate, greatly shortens the manufacturing cycle, and reduces energy consumption. Compared with existing current-assisted manufacturing processes, the present invention uses the mature temperature measurement, vacuum and hydraulic systems of the spark plasma sintering furnace itself to avoid the cost of building complex current-assisted manufacturing equipment and improve the reliability of forming. Compared with traditional gear forming dies, the present invention uses graphite as the mold material, and the designed mold device has a simple structure, high reliability, and low material and processing costs. In actual applications, due to the differences in the system of refractory high entropy alloys and the size and shape of gears, the forming parameters are often inevitably different, because it is necessary to use specific forming parameters based on the alloy properties and the structural characteristics of the gear to complete the forming of the gear component. Therefore, in specific applications, forming parameters need to be determined based on the microstructure and properties of the refractory high-entropy alloy; based on these forming parameters, the heating rate of the spark plasma sintering furnace is adjusted; and the refractory high-entropy alloy gear components are formed using the spark plasma sintering furnace. Thus, using the spark plasma sintering furnace, current-assisted forming of refractory high-entropy alloy gear components can be successfully completed, resulting in gears with high performance, high dimensional accuracy, and high surface roughness, as well as highly matched forming parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of the die for forming the refractory high entropy alloy gear component described in this application;

[0025] Figure 2 This is a schematic structural diagram of the upper die in the refractory high entropy alloy gear component forming die described in this application:

[0026] Figure 3 Schematic top view of the upper die in the forming die for the refractory high entropy alloy gear component described in this application;

[0027] Figure 4 This is a bottom view schematic diagram of the upper die in the refractory high entropy alloy gear component forming die described in this application;

[0028] Figure 5 This is a schematic top view of the female die in the forming die for the refractory high entropy alloy gear component described in this application;

[0029] Figure 6 This is a schematic front view of a female die in a forming die for a refractory high entropy alloy gear component according to the present application;

[0030] Figure 7This is a top view schematic diagram of a reinforcement sleeve in a forming die for a refractory high entropy alloy gear component described in this application;

[0031] Figure 8 This is a schematic front view of a reinforcement sleeve in a forming die for a refractory high entropy alloy gear component according to the present application;

[0032] Figure 9 Schematic top view of the lower die in the refractory high entropy alloy gear component forming die described in this application;

[0033] Figure 10 This is a schematic front view of the lower die in the refractory high entropy alloy gear component forming die described in this application;

[0034] Figure 11 Schematic diagram of the composition of the forming device in the method for forming a refractory high entropy alloy gear component described in this application;

[0035] In the figure, 1 is a spark plasma sintering furnace, 2 is a pulse power supply, 3 is an upper electrode, 4 is a lower electrode, 5 is an upper die, 6 is a concave die, 7 is a reinforcing sleeve, 8 is a lower die, 9 is a blank and 10 is a pressure unit. DETAILED DESCRIPTION

[0036] Specific implementation method 1: Combination Figures 1 to 10 The present embodiment is described. In the present embodiment, a forming die for a refractory high-entropy alloy gear component is provided. The forming die includes an upper die 5, a die 6, a reinforcing sleeve 7 and a lower die 8. The blank 9 is filled in the die 6. The upper die 5 and the lower die 8 are relatively arranged at the upper and lower ends of the die 6. The top of the upper die 5 is in close contact with the bottom end of the upper electrode 3 in the spark plasma sintering furnace 1. The bottom end of the upper die 5 extends into the die 6 and is in close contact with the blank 9. The top of the lower die 8 extends to the bottom of the die 6 and is in close contact with the blank 9. The bottom end of the lower die 8 is in close contact with the top end of the lower electrode 4 in the spark plasma sintering furnace 1. The reinforcing sleeve 7 is sleeved on the outside of the die 6 and radially constrains the die 6.

[0037] The interior of the die 6 is processed with a tooth profile cavity for filling the blank during forming;

[0038] The upper die 5 is divided into an unprocessed section 51 and a processed section 52. The unprocessed section 51 is a smooth cylinder, and the cross-sectional shape of the processed section 52 is consistent with the shape of the gear. A clearance fit is adopted between the processed section 52 and the die 6 to facilitate the longitudinal movement of the upper die 5 during forming.

[0039] The forming die for a refractory high-entropy alloy gear component provided in this embodiment consists of an upper die 5, a die 6, a reinforcing sleeve 7, and a lower die 8. The lower die 8 is a smooth cylinder and has two functions: one is to bear axial pressure and fix the die 5 in the center of the furnace cavity; the other is to act as an electrode, forming a closed circuit with the blank 9 and the upper die 5. The reinforcing sleeve 7 and the die 6 adopt a transition fit to facilitate the replacement of the die and avoid the die 6 from being broken due to excessive load during the forming process. The die 6 has a tooth profile cavity machined inside for filling the blank to form the gear teeth during forming. The upper die 5 adopts a zoned design and has two functions as a whole: one is to apply axial load to promote blank filling during forming; the other is to act as an electrode, forming a closed circuit with the blank 9 and the lower die 8.

[0040] Specific implementation method 2: Combination Figures 1 to 11 This embodiment describes a method for forming a refractory high entropy alloy gear component. The method is implemented by the following steps:

[0041] Step 1: Using a wire cutting process, the block of refractory high entropy alloy is cut into a cylindrical billet 9 according to the designed size;

[0042] Step 2: Surface treatment is performed on the cylindrical blank 9 obtained after cutting in step 1;

[0043] Step 3: Place the cylindrical blank 9 that has undergone surface treatment in Step 2 into a forming die, place the forming die with the cylindrical blank 9 into a spark plasma sintering furnace 1, and then place the spark plasma sintering furnace 1 into a pressure unit 10 to form a forming device for a refractory high-entropy alloy gear component;

[0044] Step 4: After the spark plasma sintering furnace 1 is placed in the pressure unit 10 in step 3, the position of the forming mold is adjusted so that the infrared thermometer is aligned with the junction of the concave mold 6 and the upper die 5. Subsequently, a preload of 10 MPa is applied through the pressure unit 10. At the same time, the upper electrode 3 is connected to the positive electrode of the pulse power supply 2 through a wire, and the lower electrode 4 is connected to the negative electrode of the pulse power supply 2 through a wire, and the whole forming circuit is ensured to be unobstructed;

[0045] Step 5: After the forming die position is adjusted in step 4 and the preload is applied, the door of the spark plasma sintering furnace 1 is closed, and the spark plasma sintering furnace 1 is controlled to heat up. After the spark plasma sintering furnace 1 reaches the forming temperature, the pressure unit 10 is controlled to continuously increase the load. When the increased load reaches the target load, the heat is maintained for a certain period of time to ensure that the cylindrical blank 9 is completely filled in the die 6. Then, the heating system is turned off and the temperature in the furnace cavity is lowered to room temperature to complete the forming of the refractory high-entropy alloy gear component.

[0046] Step 6: After the temperature in the spark plasma sintering furnace 1 in step 5 drops to room temperature, open the furnace door and take out the formed gear. Then, use sandpaper to polish the gear surface to obtain the target refractory high entropy alloy gear component.

[0047] The core idea of ​​the forming method of a refractory high-entropy alloy gear component provided in this embodiment is to shorten the forming cycle of the refractory high-entropy alloy gear component by taking advantage of the rapid heating characteristics of the spark plasma sintering furnace, reduce the energy consumption caused by the traditional hot forging process, and reduce the production cycle and cost. In addition, the electroplastic effect and high-temperature softening effect are conducive to improving the high-temperature deformation ability of the refractory high-entropy alloy, effectively solving the limitation of the refractory high-entropy alloy's own ultra-high room temperature and high-temperature strength on the forming of its complex components, and is expected to be applied to the forming of complex components of other high-strength and difficult-to-deform materials, and has a relatively broad application prospect.

[0048] The spark plasma sintering furnace 1 provided in this embodiment is an SPS-20T-10 sintering furnace produced by Shanghai Chenhua Technology Co., Ltd., which adopts a fast temperature measurement thermocouple, has accurate temperature measurement and fast response, has a maximum load of 20 tons, a maximum vacuum degree of 1×10-4Pa, and an infrared thermometer with a working range of 600℃~3000℃.

[0049] Specific implementation method three: Combination Figures 1 to 11 This embodiment further defines the second embodiment. In step 1, the bulk refractory high-entropy alloy comprises the following elements and contents: 18 at% to 22 at% Hf, 18 at% to 22 at% Mo, 18 at% to 22 at% Nb, 18 at% to 22 at% Ta, and 18 at% to 22 at% Ti. The refractory high-entropy alloy has a room temperature compressive yield strength of 2325 MPa, a compressive strength of 3000 MPa, a peak stress of 140 MPa at 1200°C, and a forming temperature exceeding 1200°C. Other method steps are the same as those in the second embodiment.

[0050] Specific implementation method four: Combination Figures 1 to 11 This embodiment further defines the second embodiment. In step 2, the surface treatment of the cylindrical blank 9 obtained after cutting in step 1 is performed in two steps. The first step is to polish the surface of the blank 9 with sandpaper to remove the cutting marks and oxide film. The second step is to clean the surface of the blank 9 with alcohol and dry it with a hair dryer. The other steps are the same as those in the second embodiment.

[0051] Specific implementation method five: Combination Figures 1 to 11This embodiment further defines the second embodiment. In step 4, both the upper electrode 3 and the lower electrode 4 are made of high-strength graphite, which has a compressive strength exceeding 50 MPa at temperatures below 1700° C. Other steps are the same as those in the second embodiment.

[0052] Specific implementation method six: combination Figures 1 to 11 This embodiment further defines the second embodiment. In step 4, the upper die 5, the concave die 6, and the lower die 8 are all cut from high-strength graphite rods using a slow-speed precision wire cutting process with a machining accuracy of 0.005 mm. The remaining steps are the same as those in the second embodiment.

[0053] In conjunction with the description of the fifth and sixth embodiments, in this embodiment, the electrode 3, lower electrode 4, upper die 5, die 6, and lower die 8 are all made of high-strength graphite. This is primarily because graphite is a very important high-temperature structural material. Compared to hot-working die steel, graphite does not deform at high temperatures, has excellent self-lubrication and wear resistance, and is relatively low in cost. The high-strength graphite rods are cut using a slow-speed precision wire cutting process with a machining accuracy of 0.005mm, ensuring the dimensional accuracy of the upper die 5, die 6, and lower die 8, thereby ensuring the dimensional accuracy of the subsequently formed gear components.

[0054] Specific implementation method seven: combination Figures 1 to 11 This embodiment further defines the second embodiment. After closing the door of the spark plasma sintering furnace 1 in step 5, the vacuum system of the spark plasma sintering furnace 1 is activated to reduce the vacuum level in the furnace chamber to 7.5×10-3 Pa. The spark plasma sintering furnace 1 is heated at a heating rate of 50°C / min to 70°C / min to the desired forming temperature, which is 1400°C to 1700°C. The pressure unit 10 is controlled to continuously increase the load at a loading rate of 10 MPa / min to the desired target load, which is 30 MPa to 50 MPa. The other method steps are the same as those in the second embodiment.

[0055] In this embodiment, by completing the forming work of the refractory high-entropy alloy gear component under a vacuum state, the oxidation of the refractory high-entropy alloy material during operation can be effectively avoided. The heating rate used in this application is designed based on the material properties of the refractory high-entropy alloy, avoiding the change of the properties of the refractory high-entropy alloy material due to excessive heating rate. The load rate used is also designed based on the mechanical properties of the refractory high-entropy alloy material at high temperature, avoiding the fracture of the refractory high-entropy alloy material during forming due to excessive load.

[0056] Specific implementation method eight: combination Figures 1 to 11 This embodiment will be described. This embodiment provides an application of a refractory high-entropy alloy gear component. The refractory high-entropy alloy gear component is used as a transmission component inside an aircraft engine.

[0057] With the development of fifth-generation turbofan engines, their internal temperatures can reach 2000°C, pressures reach 50 atmospheres, and rotational speeds reach 50,000 rpm. These challenges pose significant challenges to the materials used in engine blades, bearings, and gears. Currently, high-temperature ceramics and easily oxidized carbon fiber-reinforced ceramic composites, which lack metal-like damage tolerance, are difficult to use in extreme operating environments such as high temperature and high pressure. Conventional alloys based on one or two elements, such as commonly used nickel-based superalloys, titanium alloys, and TiAl alloys, are limited by the melting points of the matrix elements and therefore struggle to meet these service requirements. However, refractory high-entropy alloys (HRAs), composed of multiple (four or more) refractory metal elements (melting points above 1600°C), offer higher operating temperatures, high-temperature strength, and improved wear, oxidation, and corrosion resistance compared to traditional Ni-based superalloys. They are expected to replace Ni-based superalloys as the ideal high-temperature, load-bearing structural material for advanced aerospace engines in the future. Gear components formed from HRAs have the potential to extend the service temperature and life of aerospace engines operating under extreme conditions such as ultra-high temperatures and high pressures.

[0058] The present invention has been disclosed as above with reference to preferred embodiments, but this is not intended to limit the present invention. Any technician familiar with the present invention can make slight changes or modifications to equivalent embodiments using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention. Specific embodiments

[0059] Taking the HfMoNbTaTi refractory high entropy alloy material with the elements and contents of 22at% Hf, 18at% Mo, 21at% Nb, 19at% Ta, and 20at% Ti as the blank to prepare a refractory high entropy alloy gear component with a pitch circle diameter of 15 mm as an example, the specific operation process is as follows:

[0060] Step 1: Using a wire cutting process, the block of refractory high entropy alloy is cut into a cylindrical billet 9 according to the designed size;

[0061] Step 2: Surface treatment is performed on the cylindrical blank 9 obtained after cutting in step 1. The cut blank 9 is polished with sandpaper to remove the cutting marks and oxide film on the surface. The sandpaper is 180#, 240#, 400#, 800#, 1200#, and 1500# in sequence. After polishing, the surface of the sheet is cleaned with alcohol to remove surface oil and impurities; finally, the blank is blown dry with a hair dryer;

[0062] Step 3: placing the surface-treated blank 9 in step 2 into a forming die, placing the forming die with the cylindrical blank 9 in a spark plasma sintering furnace 1, and then placing the spark plasma sintering furnace 1 in a pressure unit (10) to form a forming device for a refractory high-entropy alloy gear component;

[0063] Step 4: After the spark plasma sintering furnace 1 is placed in the pressure unit 10 in step 3, the position of the forming mold is adjusted so that the infrared thermometer is aligned with the junction of the concave mold 6 and the upper die 5. Subsequently, a preload of 10 MPa is applied through the pressure unit 10. At the same time, the upper electrode 3 is connected to the positive electrode of the pulse power supply 2 through a wire, and the lower electrode 4 is connected to the negative electrode of the pulse power supply 2 through a wire, and the whole forming circuit is ensured to be unobstructed;

[0064] Step 5: After the forming mold position is adjusted in step 4 and the preload is applied, close the door of the spark plasma sintering furnace 1, turn on the vacuum system of the spark plasma sintering furnace, and pump the vacuum degree in the furnace chamber to 7.5×10 -3 Pa to avoid oxidation during the forming process. Subsequently, the heating system was turned on and heated to 1400°C at a heating rate of 50°C / min. After that, the load was applied to 50MPa at a loading rate of 10MPa / min. Finally, the temperature and pressure were maintained for 30 minutes to ensure complete filling of the gear.

[0065] Step 6: After the temperature in the spark plasma sintering furnace 1 in step 5 drops to room temperature, open the furnace door and take out the formed gear. Then, use sandpaper to polish the gear surface to obtain the target refractory high entropy alloy gear component.

[0066] After testing, the refractory high-entropy alloy gear component prepared by this application has a pitch circle diameter of 15 mm, qualified external dimensions, and a surface roughness of Ra0.6. The surface roughness meets the working requirements. The forming method provided by this application reduces the production cycle and cost, avoids excessive energy consumption, and is expected to be applied to the forming of complex components of other high-strength and difficult-to-deform materials, and has a relatively broad application prospect.

Claims

1. A forming die for a refractory high entropy alloy gear component, characterized by: The forming die comprises an upper die (5), a concave die (6), a reinforcing sleeve (7) and a lower die (8); a blank (9) is filled in the concave die (6); the upper die (5) and the lower die (8) are relatively arranged at the upper and lower ends of the concave die (6); the top end of the upper die (5) is in close contact with the bottom end of the upper electrode (3) in the spark plasma sintering furnace (1); the bottom end of the upper die (5) extends into the concave die (6) and is in close contact with the blank (9); the top end of the lower die (8) extends to the bottom of the concave die (6) and is in close contact with the blank (9); the bottom end of the lower die (8) is in close contact with the top end of the lower electrode (4) in the spark plasma sintering furnace (1); the reinforcing sleeve (7) is sleeved on the outside of the concave die (6) and radially constrains the concave die (6); The inner part of the die (6) is processed to have a tooth profile cavity for filling the blank (9); The upper die (5) is divided into an unprocessed section (51) and a processed section (52). The unprocessed section (51) is a smooth cylinder. The cross-sectional shape of the processed section (52) is consistent with the shape of the gear. A clearance fit is adopted between the processed section (52) and the die (6) to facilitate the longitudinal movement of the upper die (5) during forming.

2. A forming method using the forming die of the refractory high entropy alloy gear component according to claim 1, characterized in that: The method is achieved by the following steps: Step 1: Using a wire cutting process, the bulk refractory high entropy alloy is cut into cylindrical billets according to the designed size (9); Step 2: performing surface treatment on the cylindrical blank (9) obtained after cutting in step 1; Step 3: placing the cylindrical blank (9) after surface treatment in step 2 into a forming die, placing the forming die with the cylindrical blank (9) in a spark plasma sintering furnace (1), and then placing the spark plasma sintering furnace (1) in a pressure unit (10) to form a forming device for a refractory high entropy alloy gear component; Step 4: After the spark plasma sintering furnace (1) is placed in the pressure unit (10) in step 3, the position of the forming mold is adjusted so that the infrared thermometer is aligned with the junction of the concave mold (6) and the upper pressure mold (5). Subsequently, a preload of 10 MPa is applied through the pressure unit (10), and at the same time, the upper electrode (3) is connected to the positive electrode of the pulse power supply (2) through a wire, and the lower electrode (4) is connected to the negative electrode of the pulse power supply (2) through a wire and the whole forming circuit is ensured to be unobstructed; Step 5: After the position of the forming mold is adjusted in step 4 and the preload is applied, the door of the spark plasma sintering furnace (1) is closed, the spark plasma sintering furnace (1) is controlled to heat up, and after the spark plasma sintering furnace (1) reaches the forming temperature, the pressure unit (10) is controlled to continuously increase the load. When the increased load reaches the target load, the temperature is kept for a certain period of time to ensure that the cylindrical blank (9) is completely filled in the die (6), and then the heating system is turned off to reduce the temperature in the furnace chamber to room temperature to complete the forming of the refractory high entropy alloy gear component; Step 6: After the temperature in the spark plasma sintering furnace (1) in step 5 drops to room temperature, open the furnace door and take out the formed gear. Then, use sandpaper to polish the gear surface to obtain the target refractory high entropy alloy gear component.

3. The method for forming a refractory high entropy alloy gear component according to claim 2, characterized in that: The constituent elements and contents of the bulk refractory high-entropy alloy in step 1 are: 18at%~22at% Hf, 18at%~22at% Mo, 18at%~22at% Nb, 18at%~22at% Ta, and 18at%~22at% Ti. The refractory high-entropy alloy has a room temperature compressive yield strength of 2325 MPa, a compressive strength of 3000 MPa, a peak stress of 140 MPa at 1200°C, and a forming temperature exceeding 1200°C.

4. The method for forming a refractory high entropy alloy gear component according to claim 3, characterized in that: In step 2, the surface treatment of the cylindrical blank (9) obtained after cutting in step 1 is carried out in two steps. The first step is to use sandpaper to polish and remove the cutting marks and oxide film on the surface of the blank (9). The second step is to clean the surface of the blank (9) with alcohol and blow dry it with a hair dryer.

5. The method for forming a refractory high entropy alloy gear component according to claim 4, characterized in that: In step 4, the upper electrode (3) and the lower electrode (4) are both made of high-strength graphite, which has a compressive strength of more than 50 MPa at a temperature below 1700°C.

6. The method for forming a refractory high entropy alloy gear component according to claim 5, characterized in that: In step 4, the upper die (5), the concave die (6) and the lower die (8) are all cut from high-strength graphite rods, and a slow-moving precision wire cutting process with a processing accuracy of 0.005 mm is adopted when cutting the high-strength graphite rods.

7. The method for forming a refractory high entropy alloy gear component according to claim 6, characterized in that: After closing the door of the spark plasma sintering furnace (1) in step 5, the vacuum system of the spark plasma sintering furnace (1) is started to reduce the vacuum degree in the furnace chamber to 7.5×10-3Pa.

8. The method for forming a refractory high entropy alloy gear component according to claim 7, characterized in that: In step 5, when controlling the spark plasma sintering furnace (1) to heat up, the temperature is heated at a heating rate of 50°C / min to 70°C / min to the desired forming temperature, and the desired forming temperature is 1400°C to 1700°C.

9. The method for forming a refractory high entropy alloy gear component according to claim 8, characterized in that: In step 5, when the pressure applying unit (10) is controlled to continuously increase the load, the load is applied at a load rate of 10 MPa / min to a desired target load, and the desired target load is 30 MPa to 50 MPa.

10. An application of a refractory high-entropy alloy gear component produced by the forming method of any one of claims 2 to 9, characterized in that: Refractory high entropy alloy gear components are used as transmission components inside aircraft engines.

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