Silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy and preparation method thereof

Abstract

The invention discloses a silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy and a preparation method thereof, and relates to the technical field of high-entropy alloys. The method comprises the following steps: mixing powder of five metal elements of W, Ti, Ta, V and Cr according to a certain molar ratio, and then carrying out ball milling to obtain mixed powder; uniformly dispersing the mixed powder and the SiC fiber with the deposited pyrolytic carbon interface in absolute ethyl alcohol, and carrying out roller ball milling to obtain a suspension; placing the powder mixture in a discharge plasma sintering furnace to obtain a sintered sample; and the sintered sample is subjected to heat treatment for 4-6 h, and the silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy is obtained. The SiC fiber toughened tungsten-containing refractory high-entropy alloy which is good in high-temperature stability and good in high-temperature mechanical property is adopted, the problem that the high-entropy alloy in the nuclear field is insufficient in toughness at the high temperature is effectively solved, and meanwhile good heat conductivity is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-entropy alloys, and particularly relates to a silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy and a preparation method thereof. Background Art

[0002] Fusion energy has outstanding advantages such as rich resources, environmental friendliness, and inherent safety. Specifically, nuclear fusion uses light elements such as deuterium and tritium as fuels, which are relatively abundant on Earth and can be extracted from seawater; compared with nuclear fission, the waste generated by nuclear fusion reactions is mainly inert helium gas and does not produce long-lived high-radioactive waste; nuclear fusion reactions do not lead to chain nuclear fission reactions, so there is no risk of nuclear explosion. Therefore, the research on fusion energy has received great attention internationally. Currently, magnetic confinement fusion (Tokamak) is considered the most promising approach for controllable nuclear fusion.

[0003] As a core component for the successful operation of a magnetic confinement fusion reactor, plasma-facing materials usually face extreme working conditions such as high-flux D / T / He particle bombardment, 14 MeV high-energy neutron irradiation, steady-state and transient heat flux shocks, and electromagnetic radiation. Currently, there is no material that can fully meet this service environment. Plasma-facing materials can generally be divided into low atomic number materials and high atomic number materials. In the early development of plasma-facing materials, low atomic number materials, such as carbon materials and beryllium materials, received more attention from researchers due to their good compatibility with plasma and low impurity introduction. However, their sputtering yields are relatively high, which easily causes plasma pollution. Therefore, researchers have shifted their research focus to high atomic number materials. Among them, tungsten has become the most ideal high atomic number material due to its high melting point, high thermal conductivity, resistance to physical and chemical sputtering, and low T retention rate. However, many disadvantages of tungsten, such as high ductile-brittle transition temperature, poor machinability, irradiation embrittlement, and insufficient strength, limit its application in the nuclear fusion system.

[0004] In recent years, the developed high-entropy alloys have become a current research hotspot due to their four effects of lattice distortion, sluggish diffusion, high entropy, and cocktail, resulting in higher specific strength, better fracture resistance, tensile strength, corrosion resistance, and oxidation resistance compared to traditional alloys.

[0005] Some prior arts disclose that high-entropy alloys provide a new direction for the design and manufacture of breakthrough materials in advanced fusion reactors due to their characteristics such as low thermal neutron absorption cross-section, radiation resistance, and high-temperature mechanical properties. It is disclosed in the prior art that the BCC structure in HEAs has more excellent radiation resistance, but it needs to be strengthened and toughened. At the same time, the prior art also discloses W 0.5TaTiVCr has a room-temperature compression property of 2100 MPa, a hardness of 788 HV, and better irradiation resistance than pure tungsten. However, its fracture strain of only 5.4% indicates that the material needs to be toughened. Those skilled in the art use tungsten particles, tungsten short fibers, and tungsten meshes to toughen W 0.5 TaTiVCr, effectively improving the fracture toughness of W 0.5 TaTiVCr. However, pure tungsten will recrystallize above 1000 °C, reducing its mechanical properties, which will lead to a decrease in the toughening effect.

[0006] In summary, the disadvantages in the prior art include: 1) Tungsten has become the most ideal high atomic number material due to its high melting point, high thermal conductivity, resistance to physical and chemical sputtering, and low T retention rate. However, many disadvantages of tungsten, such as high ductile-brittle transition temperature, poor machinability, irradiation embrittlement, and insufficient strength, limit its application in the nuclear fusion system. 2) Tungsten-containing refractory high-entropy alloys have better strength and irradiation resistance than pure tungsten, but they have poor toughness. Tungsten-containing refractory high-entropy alloys can be toughened by tungsten particles, tungsten fibers, and tungsten meshes. However, pure tungsten will recrystallize at high temperatures, and the toughening method using tungsten materials has poor effects at high temperatures. Summary of the Invention

[0007] In view of the deficiencies in the above background art, the present invention provides a silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy and a preparation method thereof. This method uses SiC fibers with good high-temperature stability and high-temperature mechanical properties to toughen tungsten-containing refractory high-entropy alloys, effectively improving the problem of insufficient toughness of high-entropy alloys in the nuclear field at high temperatures, and having good thermal conductivity at the same time.

[0008] The first object of the present invention is to provide a preparation method of a silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy, including the following steps: Deposit a pyrolytic carbon interface on the SiC fiber to obtain the SiC fiber after depositing the pyrolytic carbon interface; Mix powders of five metal elements of W, Ti, Ta, V, and Cr in a certain molar ratio, and then perform ball milling to obtain a mixed powder; Disperse the mixed powder and the SiC fiber after depositing the pyrolytic carbon interface evenly in absolute ethanol, and then perform drum ball milling to obtain a suspension; Perform vacuum sedimentation on the suspension, and then perform drying to obtain a powder mixture; Place the powder mixture in a spark plasma sintering furnace, and perform vacuum sintering at 1400 - 1600 °C for 8 - 12 min to obtain a sintered specimen; Perform heat treatment on the sintered specimen at 1200 - 1400 °C for 4 - 6 h to obtain the silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy.

[0009] Preferably, the molar ratio of the five metal elements of W, Ti, Ta, V and Cr is 1-4:1:1:1:1.

[0010] Preferably, during the process of obtaining the mixed powder, the ball milling parameters are: ball-to-material ratio of 5:1, rotation speed of 200-300 r / min, and ball milling time of 24-72 h.

[0011] Preferably, when the mixed powder and the SiC fibers after depositing the pyrolytic carbon interface are uniformly dispersed in absolute ethanol, uniform dispersion is carried out by propeller stirring. Among them, the SiC fibers account for 5-30% of the total volume; the parameters during propeller stirring are: propeller rotation speed of 300-450 r / min, and stirring time of 3-6 h.

[0012] Preferably, the parameters of the drum ball milling are: ball-to-material ratio of 5:1, rotation speed of 200-300 r / min, and ball milling time of 12-24 h.

[0013] Preferably, vacuum sedimentation is carried out for 3-6 h; the drying temperature is 70-90 °C.

[0014] Preferably, during sintering, the heating rate is 80-100 °C / min, the cooling rate is 80-100 °C / min, and the pressure is 30-45 MPa.

[0015] Preferably, when depositing the pyrolytic carbon interface on the SiC fibers, it includes: using propylene as the precursor gas source, using argon as the dilution gas, the deposition temperature is 870 ± 10 °C, the deposition pressure is 3 ± 1 kPa, and the deposition time is 48-120 h to deposit the pyrolytic carbon interface on the SiC fibers.

[0016] The second object of the present invention is to provide a silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy. In this high-entropy alloy, the SiC fibers account for 5-30% of the total volume fraction of the material, and the thickness of the pyrolytic carbon interface is 100-330 nm.

[0017] The third object of the present invention is to provide an application of a silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy in the nuclear industry.

[0018] Compared with the prior art, the beneficial effects of the present invention are: The present invention provides a SiC fiber - toughened tungsten - containing refractory high - entropy alloy and a preparation method thereof. The present invention selects SiC fibers which have the advantages of a small neutron absorption cross - section, low elemental activation, good anti - irradiation damage performance, excellent high - temperature stability, etc. The SiC fibers are used as toughening fibers for a high - entropy alloy composed of five elements, namely W, Ti, Ta, V, and Cr. The pyrolytic carbon (PyC) interface is selected as the composite material interface and the interface preparation is completed, effectively improving the problem of insufficient toughness of the high - entropy alloy in the nuclear field at high temperatures, and having good thermal conductivity at the same time.

[0019] The present invention combines a variety of preparation techniques, such as vacuum sedimentation, chemical vapor infiltration (CVI), and spark plasma sintering technology. Among them, vacuum sedimentation can alleviate the uneven distribution of fibers in the matrix; chemical vapor infiltration (CVI) can prepare a pyrolytic carbon (PyC) interface with high purity, high density, and good bonding on the surface of SiC fibers; the spark plasma sintering technology can combine SiC fibers with the high - entropy alloy matrix, with high efficiency, dense sintering, and can realize the control of the grain size of the material. Brief Description of the Drawings

[0020] Figure 1 Process preparation flow chart; Figure 2 Physical picture of the SiC fiber - toughened tungsten - containing refractory high - entropy alloy block prepared by the present invention; Figure 3 Microscopic characterization diagram of SiC fibers with pyrolytic carbon; Figure 4 XRD characterization diagram of fiber - toughened tungsten - containing high - entropy alloy; Figure 5 SEM characterization diagram of fiber - toughened tungsten - containing high - entropy alloy; Figure 6 Material thermal conductivity; Figure 7 Material fracture toughness; Figure 8 SiC sf (0 / 10 / 20 vol. %) / W RHEAs Fracture toughness test results of the composite material at 1100 °C (a) Fracture toughness (b) Growth rate compared with the low - temperature fracture toughness. Detailed Description of the Invention

[0021] In order to enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and drawings, but the specific embodiments cited do not limit the present invention.

[0022] Based on the SiC fiber, which is a non-oxide ceramic fiber, has been commercialized and has the advantages of a small neutron absorption cross-section, low elemental activation, good anti-irradiation damage performance, excellent high-temperature stability, etc., it is an ideal high-performance composite material reinforcing fiber in the nuclear field. In the present invention, SiC fibers are selected to toughen the tungsten-containing refractory high-entropy alloy. At the same time, a pyrolytic carbon interface is prepared on the surface of the SiC fibers to improve the toughening effect. Therefore, the object of the present invention is to provide a silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy and its preparation method.

[0023] The present invention provides a silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy and its preparation method. By introducing SiC fibers with a pyrolytic carbon (PyC) interface into a high-entropy alloy composed of five elements, namely W, Ti, Ta, V, and Cr, a silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy with good high-temperature toughness and a pyrolytic carbon interface can be obtained.

[0024] To achieve the above object, a preparation method of a silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy includes the following steps: Deposit a pyrolytic carbon interface on the SiC fibers to obtain SiC fibers after depositing the pyrolytic carbon interface; Mix the powders of five metal elements, namely W, Ti, Ta, V, and Cr, in a certain molar ratio, and then perform ball milling to obtain a mixed powder; Disperse the mixed powder and the SiC fibers after depositing the pyrolytic carbon interface evenly in anhydrous ethanol, and then perform drum ball milling to obtain a suspension; Perform vacuum sedimentation on the suspension, and then perform drying to obtain a powder mixture; Place the powder mixture in a spark plasma sintering furnace, and perform vacuum sintering at 1400 - 1600 °C for 8 - 12 min to obtain a sintered sample; Perform heat treatment on the sintered sample at 1200 - 1400 °C for 4 - 6 h to obtain the silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy.

[0025] The present invention selects SiC fibers with the advantages of a small neutron absorption cross-section, low elemental activation, good anti-irradiation damage performance, excellent high-temperature stability, etc. As the toughening fibers of a high-entropy alloy composed of five elements, namely W, Ti, Ta, V, and Cr, a pyrolytic carbon (PyC) interface is selected as the composite material interface and the interface preparation is completed, effectively improving the problem of insufficient toughness of the high-entropy alloy in the nuclear field at high temperatures, and having good thermal conductivity at the same time.

[0026] It should be noted that, generally, brittle materials are toughened by alloying, heat treatment, nanostructuring, and by preparing composite materials through adding particles, whiskers, fibers, etc. The present invention toughens a tungsten-containing high-entropy alloy substrate by adding SiC fibers in combination with the preparation process. The mechanism is as follows: 1) The SiC fibers bridge the cracks to delay crack propagation; 2) When the crack propagates, the fibers are pulled out from the substrate to dissipate energy and slow down the crack propagation; 3) The presence of the fibers changes the crack propagation path, improves the energy absorption, and slows down the crack propagation. The role of the pyrolytic carbon interface is to allow interface debonding and fiber pull-out, dissipate energy, and match the thermal expansion coefficients of the fiber and the matrix through the interface layer to reduce the thermal mismatch stress during the processing. Since there is currently a way to toughen tungsten-containing high-entropy alloys by adding tungsten fibers, the problem of recrystallization of tungsten fibers at high temperatures affects the mechanical properties of tungsten fibers at high temperatures, thereby reducing the toughening effect. Therefore, the present invention proposes to use SiC fibers and pyrolytic carbon interfaces to improve the problem of insufficient toughness of tungsten-containing high-entropy alloys at high temperatures.

[0027] Among them, the molar ratio of the five metal elements of W, Ti, Ta, V, and Cr is 1 to 4:1:1:1:1.

[0028] During the process of obtaining the mixed powder, the ball milling parameters are: the ball-to-powder ratio is 5:1, the rotation speed is 200 - 300 r / min, and the ball milling time is 24 - 72 h.

[0029] When the mixed powder and the SiC fibers after depositing the pyrolytic carbon interface are uniformly dispersed in absolute ethanol, they are uniformly dispersed by propeller stirring. Among them, the SiC fibers account for 5 - 30% of the total volume; the parameters during propeller stirring are: the propeller rotation speed is 300 - 450 r / min, and the stirring time is 3 - 6 h.

[0030] The parameters of the drum ball milling are: the ball-to-powder ratio is 5:1, the rotation speed is 200 - 300 r / min, and the ball milling time is 12 - 24 h.

[0031] Vacuum sedimentation for 3 - 6 h; the drying temperature is 70 - 90 °C.

[0032] During sintering, the heating rate is 80 - 100 °C / min, the cooling rate is 80 - 100 °C / min, and the pressure is 30 - 45 MPa.

[0033] When depositing the pyrolytic carbon interface on the SiC fibers, it includes: using propylene as the precursor gas source, using argon as the dilution gas, the deposition temperature is 870 ± 10 °C, the deposition pressure is 3 ± 1 kPa, and the deposition time is 48 - 120 h to deposit the pyrolytic carbon interface on the SiC fibers.

[0034] In the present invention, a certain volume fraction of uniformly dispersed SiC fibers with a pyrolytic carbon interface is introduced into the tungsten-containing high-entropy alloy through the processes of propeller stirring, drum ball milling, and vacuum sedimentation for toughening.

[0035] It should be noted that chemical vapor deposition (CVD): Chemical vapor deposition is a chemical engineering technology. This technology mainly uses one or several gaseous compounds or elements containing thin film elements to generate a thin film on the surface of a substrate through a chemical reaction.

[0036] Pyrolytic carbon (PyC): A carbonaceous material formed by the thermal decomposition of hydrocarbon gases on the surface of a hot solid and deposited on the surface of the solid.

[0037] Vacuum sedimentation: Placing the suspension in a vacuum container to allow the powder and fibers to sediment naturally.

[0038] Exemplarily, a preparation method of a silicon carbide fiber toughened tungsten-containing refractory high-entropy alloy, the preparation flow chart is as Figure 1 shown. The SiC fibers account for 5 - 30% of the total volume of the material, and the thickness of the pyrolytic carbon interface is 100 - 330 nm. The preparation steps are as follows: Step 1: Using propylene as the precursor gas source and argon as the dilution gas, with a deposition temperature of 870 °C, a deposition pressure of 3 kPa, and a deposition time of 48 - 120 h, deposit a pyrolytic carbon (PyC) interface on the SiC fibers.

[0039] Step 2: Mix the powders of five metal elements, namely W, Ti, Ta, V, and Cr, in a certain molar ratio, and then perform high-energy ball milling; by means of the collision, friction, and extrusion of the ball milling medium, the refinement and mixing of the powders are achieved. Among them, the ball-to-powder ratio is 5:1, the rotation speed is 200 - 300 r / min, and the ball milling time is 24 - 72 h.

[0040] Step 3: Sequentially add the powder obtained in Step 2 and the SiC fibers after depositing the pyrolytic carbon (PyC) interface into absolute ethanol, where the SiC fibers account for 5 - 30% of the total volume, and obtain a uniformly dispersed suspension through propeller stirring; propeller stirring disperses the SiC fibers to avoid agglomeration, and at the same time evenly mixes the fibers and the powder. Among them, the stirring parameters are: the propeller rotation speed is 300 - 450 r / min, and the stirring time is 3 - 6 h.

[0041] Step 4: Perform drum ball milling on the suspension obtained in Step 3; drum ball milling further increases the uniformity of the fiber distribution in the powder. Among them, the ball-to-powder ratio is 5:1, the rotation speed is 200 - 300 r / min, and the ball milling time is 12 - 24 h.

[0042] Step 5: Perform vacuum sedimentation on the suspension obtained in Step 4 for 3 - 6 h.

[0043] Step 6: Dry the solution in Step 5 at 80 °C, take out the grinding balls, and obtain a uniformly mixed powder mixture. Vacuum sinter it in a spark plasma sintering furnace. The spark plasma sintering parameters are as follows: heating rate 80 - 100 °C / min, temperature 1400 - 1600 °C, holding time 8 - 12 min, cooling rate 80 - 100 °C / min, and pressure 30 - 45 MPa.

[0044] Step 7: Heat-treat the specimen obtained in Step 6 at 1200 - 1400 °C and hold for 4 - 6 h.

[0045] The present invention provides a SiC fiber-reinforced tungsten-containing refractory high-entropy alloy. In this high-entropy alloy, the SiC fibers account for 5 - 30% of the total volume fraction of the material, and the thickness of the pyrolytic carbon interface is 100 - 330 nm.

[0046] The present invention provides an application of a SiC fiber-reinforced tungsten-containing refractory high-entropy alloy in the nuclear industry.

[0047] It should be noted that the experimental methods used in the present invention are all conventional methods unless otherwise specified; the reagents and materials used can be obtained in the market unless otherwise specified.

[0048] Example A preparation method of a SiC fiber-reinforced tungsten-containing refractory high-entropy alloy, the preparation flow chart is as Figure 1 shown. The SiC fibers account for 5 - 30% of the total volume fraction of the material, and the thickness of the pyrolytic carbon interface is 100 - 330 nm. The preparation steps are as follows: Step 1: Using propylene as the precursor gas source and argon as the dilution gas, with a deposition temperature of 870 °C, a deposition pressure of 3 kPa, and a deposition time of 48 - 120 h, deposit a pyrolytic carbon (PyC) interface on the SiC fibers.

[0049] Step 2: Mix the powders of five metal elements, namely W, Ti, Ta, V, and Cr, in a certain molar ratio, and then perform high-energy ball milling; the ball-to-material ratio is 5:1, the rotation speed is 200 - 300 r / min, and the ball milling time is 24 - 72 h.

[0050] Step 3: Sequentially add the powder obtained in Step 2 and the SiC fibers after depositing the pyrolytic carbon (PyC) interface into anhydrous ethanol, where the SiC fibers account for 5 - 30% of the total volume, and obtain a uniformly dispersed suspension by propeller stirring; the stirring parameters are: propeller rotation speed 300 - 450 r / min, and stirring time 3 - 6 h.

[0051] Step 4: Carry out roller ball milling on the suspension obtained in Step 3; the ball-to-material ratio is 5:1, the rotation speed is 200 - 300 r / min, and the ball milling time is 12 - 24 h.

[0052] Step 5: Carry out vacuum sedimentation on the suspension obtained in Step 4 for 3 - 6 h.

[0053] Step 6: Dry the solution in Step 5 at 80 °C, take out the grinding balls, and obtain a uniformly mixed powder mixture, and carry out vacuum sintering on it in a spark plasma sintering furnace. The spark plasma sintering parameters are: the heating rate is 80 - 100 °C / min, the temperature is 1400 - 1600 °C, the holding time is 8 - 12 min, the cooling rate is 80 - 100 °C / min, and the pressure is 30 - 45 MPa.

[0054] Step 7: Carry out heat treatment on the specimen obtained in Step 6 at 1200 - 1400 °C and hold for 4 - 6 h.

[0055] The process parameters of each example are shown in Table 1 below.

[0056] Table 1 Process parameters of each example

[0057] In order to illustrate the relevant properties of the tungsten-containing refractory high-entropy alloy toughened by SiC fibers prepared by the method provided by the present invention, it is described in conjunction with the accompanying drawings.

[0058] Figure 2 Physical diagram of the tungsten-containing refractory high-entropy alloy block toughened by SiC fibers prepared by the present invention; this figure shows the sample provided in Example 10, and the sintering state of the sample is good.

[0059] Figure 3 Microscopic characterization diagram of SiC fibers with pyrolytic carbon; this figure shows the SiC fibers used in the sample of Example 9, and (a) and (b) are the SEM diagram and EDS diagram of the SiC fibers, and the figure shows that the combination between the fibers and the interface is tight and relatively uniform.

[0060] Figure 4 XRD characterization diagram of fiber-reinforced tungsten-containing high-entropy alloy; Figure 4 Corresponding to Example 10, Example 11, Example 12, and Example 13 according to the fiber content respectively. The XRD pattern shows that the addition of SiC fibers does not significantly affect the crystal structure of the tungsten-containing high-entropy alloy.

[0061] Figure 5 SEM characterization diagram of fiber-reinforced tungsten-containing high-entropy alloy; Figure 5 Corresponding to Example 10, Example 11, and Example 12 according to the fiber content respectively. Figure 5It is shown that when the fiber content is low, the fibers are better dispersed in the substrate and there is less agglomeration.

[0062] Figure 6 Thermal conductivity of the material; Figure 6 W in HEAs Corresponding to the sample sintered without adding SiC fibers in Example 10, the remaining three curves correspond to Example 10, Example 11, and Example 12 according to the fiber volume fraction respectively. When the fiber addition is less, the influence on the thermal conductivity of the material is smaller, while after increasing the fiber content, the thermal conductivity of the material may be reduced due to the existence of interfaces.

[0063] Figure 7 Fracture toughness of the material; Figure 7 W in RHEAs Corresponding to the sample sintered without adding SiC fibers in Example 10, the others correspond to Example 10, Example 11, and Example 12 according to the fiber volume fraction respectively. Adding a small amount of SiC fibers can effectively toughen the tungsten-containing high-entropy alloy.

[0064] Figure 8 SiC sf (0 / 10 / 20 vol. %) / W RHEAs Fracture toughness test results of the composite material at 1100 °C (a) Fracture toughness (b) Growth rate compared to the low-temperature fracture toughness; Figure 8 In, W RHEAs Corresponding to the sample sintered without adding SiC fibers in Example 10, the others correspond to Example 11 and Example 12 according to the fiber volume fraction respectively. It shows that the addition of SiC fibers effectively improves the fracture toughness of the tungsten-containing high-entropy alloy at high temperature (1100 °C).

[0065] It should be noted that before preparing materials by sintering multiple powders, ball milling is always adopted to fully mix the powders to prevent the occurrence of multiple phases and uneven composition distribution in the sintered materials. Uniform powder distribution can also reduce the rapid grain growth in local areas during sintering and avoid uneven material properties. Therefore, ball milling is always carried out before using multiple powders for sintering. In the alloys mentioned in the present invention, if ball milling is not carried out, the required uniformly distributed high-entropy phase cannot be obtained necessarily, resulting in the material lacking necessary properties such as high mechanical properties and radiation resistance.

[0066] The present invention describes the preferred embodiments and their effects. However, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concepts. Therefore, the appended claims are intended to be interpreted to include the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0067] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a tungsten-containing refractory high entropy alloy toughened with silicon carbide fibers, characterized in that: The following steps are involved: Depositing a pyrolytic carbon interface on the SiC fiber to obtain a SiC fiber after the pyrolytic carbon interface is deposited; Powders of five metal elements, W, Ti, Ta, V and Cr, are mixed in a certain molar ratio and ball-milled to obtain a mixed powder; The mixed powder and SiC fibers after the pyrolytic carbon interface is uniformly dispersed in anhydrous ethanol, and then subjected to roller ball milling to obtain a suspension; The suspension is subjected to vacuum sedimentation and then dried to obtain a powder mixture; The powder mixture is placed in a spark plasma sintering furnace and vacuum sintered at 1400-1600°C for 8-12 min to obtain a sintered sample; The sintered sample is heat treated at 1200-1400°C for 4-6 h to obtain the silicon carbide fiber reinforced tungsten-containing refractory high entropy alloy.

2. The method for preparing the silicon carbide fiber toughened tungsten-containing refractory high entropy alloy according to claim 1, characterized in that: The molar ratio of the five metal elements W, Ti, Ta, V and Cr is 1-4:1:1:1:

1.

3. The method for preparing the silicon carbide fiber toughened tungsten-containing refractory high entropy alloy according to claim 1, characterized in that: In the process of obtaining the mixed powder, the ball milling parameters are: ball-to-material ratio 5:1, rotation speed 200-300 r / min, and ball milling time 24-72h.

4. The method for preparing the silicon carbide fiber toughened tungsten-containing refractory high entropy alloy according to claim 1, characterized in that: When the mixed powder and the SiC fibers after the pyrolytic carbon interface is uniformly dispersed in anhydrous ethanol, propeller stirring is used for uniform dispersion, wherein the SiC fibers account for 5-30% of the total volume; the parameters during propeller stirring are: propeller speed 300-450r / min, stirring time 3-6h.

5. The method for preparing the silicon carbide fiber toughened tungsten-containing refractory high entropy alloy according to claim 1, characterized in that: The parameters of the drum ball mill are: ball-to-material ratio 5:1, rotation speed 200-300 r / min, and ball milling time 12-24 h.

6. The method for preparing the silicon carbide fiber toughened tungsten-containing refractory high entropy alloy according to claim 1, characterized in that: Vacuum sedimentation for 3-6 hours; drying temperature is 70~90℃.

7. The method for preparing the silicon carbide fiber toughened tungsten-containing refractory high entropy alloy according to claim 1, characterized in that: During sintering, the heating rate is 80-100℃ / min, the cooling rate is 80-100℃ / min, and the pressure is 30-45 MPa.

8. The method for preparing the silicon carbide fiber toughened tungsten-containing refractory high entropy alloy according to claim 1, characterized in that: When depositing a pyrolytic carbon interface on the SiC fiber, the method includes: using propylene as a precursor gas source, using argon as a diluent gas, a deposition temperature of 870±10°C, a deposition pressure of 3±1kPa, and a deposition time of 48-120 h to deposit a pyrolytic carbon interface on the SiC fiber.

9. A silicon carbide fiber toughened tungsten-containing refractory high entropy alloy prepared by the method according to any one of claims 1 to 8, characterized in that: In this high entropy alloy, SiC fibers account for 5-30% of the total volume fraction of the material, and the pyrolytic carbon interface thickness is 100-330nm.

10. Use of the silicon carbide fiber toughened tungsten-containing refractory high entropy alloy according to claim 9 in the nuclear industry.

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