A nuclear gap element doped high-entropy alloy material and a preparation method thereof

Abstract

This invention discloses a high-entropy alloy material doped with interstitial elements for nuclear applications, denoted as (Ti). a V b Cr c Al d Zr e )X f X is selected from one of the interstitial elements O, B, and N. This invention also discloses a method for preparing nuclear interstitial element-doped high-entropy alloy materials. This method includes the following steps: 1. Mechanical alloying; 2. Sintering; 3. Rolling; 4. Heat treatment, to obtain nuclear interstitial element-doped high-entropy alloy materials. This invention introduces interstitial elements to occupy the interstitial positions of the high-entropy alloy through mechanical alloying and sintering, hindering atomic movement, improving the strength of the high-entropy alloy, and stabilizing the single-phase solid solution structure of the high-entropy alloy. Subsequent rolling and heat treatment refine the grain size of the high-entropy alloy, promote the generation of dislocation cross-slip, and improve the high-temperature strength and ductility of the high-entropy alloy. It is suitable for new high-temperature nuclear reactor shells, pipes, and core structural components.

Description

Technical Field

[0001] This invention belongs to the field of advanced nuclear energy structural materials technology, specifically relating to a nuclear interstitial element-doped high-entropy alloy material and its preparation method. Background Technology

[0002] New high-temperature nuclear reactors, such as fourth-generation nuclear reactors, place extremely stringent requirements on structural materials. These materials need to operate for extended periods under extreme conditions of high temperature, high pressure, and intense radiation, while maintaining excellent mechanical properties and structural stability. Traditional nuclear structural materials, such as austenitic stainless steel and zirconium alloys, face problems such as decreased creep strength, radiation swelling, and radiation embrittlement under higher temperatures and stronger radiation, making them unsuitable for the design requirements of next-generation reactors.

[0003] High-entropy alloys, as a novel type of multi-principal element alloy, exhibit excellent high-temperature strength, good radiation resistance, and outstanding corrosion resistance due to their high-entropy effect, lattice distortion effect, hysteresis diffusion effect, and "cocktail" effect, making them a highly promising new structural material for nuclear applications. However, some high-entropy alloys may undergo phase decomposition or ordering during long-term high-temperature service, leading to performance degradation; simultaneously, their plasticity sometimes fails to meet the requirements of engineering applications. Chinese invention patent application CN202510843230.2, "TiAlVNbZrSc-based Lightweight Refractory High-Entropy Alloy and Preparation Method Thereof," describes obtaining a high-entropy alloy with good strength and plasticity by adjusting the ratio of elements such as Ti, V, Al, and Nb, but it mainly focuses on room-temperature performance and lacks targeted design for high-temperature stability. Furthermore, relying solely on substitutional solid solution strengthening still leaves room for improvement in both high-temperature strength and plasticity.

[0004] Therefore, there is an urgent need to develop a high-entropy alloy material for nuclear applications that combines excellent high-temperature strength, good plasticity, high phase stability, and potential radiation resistance. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a high-entropy alloy material doped with interstitial elements for nuclear applications. This high-entropy alloy material, by introducing interstitial atoms O, B, or N, stabilizes the intrinsic structure of the high-entropy alloy, thereby providing radiation resistance and corrosion resistance, hindering dislocation movement and atomic diffusion, significantly improving the high-temperature strength and thermal stability of the alloy, promoting dislocation cross-slip and enhancing dislocation migration, and ultimately improving the strength and plasticity of the high-entropy alloy.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a high-entropy alloy material doped with interstitial elements for nuclear applications, characterized in that the high-entropy alloy material is denoted by the molar ratio of each constituent element as (Ti... a V b Crc Al d Zr e )X f X is selected from one of the interstitial elements O, B and N, and satisfies: 20≤a≤40, 15≤b≤30, 10≤c≤25, 10≤d≤25, 5≤e≤20, 0.1≤f≤5, and a+b+c+d+e+f=100.

[0007] The interstitial element-doped high-entropy alloy material of the present invention has the following effects by introducing interstitial atoms O, B, or N: 1. Interstitial elements can stabilize the intrinsic structure of BCC (body-centered cubic) high-entropy alloys, playing a role in radiation resistance and corrosion resistance; 2. The atomic radii of interstitial elements and metallic elements are significantly different. While maintaining the single-phase solid solution structure of the high-entropy alloy, the doping of interstitial atoms O, B, or N occupies the interstitial positions of the alloy lattice, generating a strong lattice distortion effect and interstitial solid solution strengthening effect, which can effectively pin dislocations, hinder dislocation movement and atomic diffusion, and significantly improve the high-temperature strength and thermal stability of the alloy; 3. Interstitial elements can easily combine with other principal components to form interstitial nanophases, promoting dislocation cross-slip and enhancing dislocation migration, thereby improving the strength and plasticity of the high-entropy alloy.

[0008] Furthermore, oxygen (O) exhibits a significant solid solution strengthening effect: O atoms occupy interstitial positions in the crystal lattice, effectively pinning dislocations and significantly improving the alloy's strength and hardness at a very low cost. Simultaneously, a suitable amount of oxygen helps form ordered oxygen complexes, potentially improving plasticity. Boron (B) contributes to grain boundary strengthening and grain refinement: Boron readily segregates at grain boundaries or forms dispersed nano-borides, effectively pinning grain boundaries and inhibiting grain growth at high temperatures, thus refining the microstructure. This not only significantly enhances room temperature strength and hardness but also improves the alloy's high-temperature creep resistance and thermal stability, while the addition of boron causes minimal damage to plasticity. Nitrogen (N) enhances surface hardening and corrosion resistance: Nitrogen readily forms high-hardness nitrides with elements such as titanium, creating a dense strengthening layer on the alloy surface, significantly improving wear resistance and high-temperature oxidation resistance. In addition, interstitial solid solution of nitrogen also contributes to strength and can improve the alloy's passivation behavior in corrosive media by regulating the nitrogen potential, enhancing resistance to localized corrosion (such as pitting and crevice corrosion).

[0009] In addition, the present invention also discloses a method for preparing interstitial element-doped high-entropy alloy materials for nuclear applications, characterized in that the method includes the following steps: Step 1, Mechanical alloying: Pour elemental metal powders of Ti, V, Cr, Al and Zr and ceramic powders containing interstitial elements O, B or N into a ball mill jar for ball milling and mechanical alloying to obtain interstitial element-doped high-entropy alloy powder. Step 2, Sintering and Shaping: The interstitial element-doped high-entropy alloy powder obtained in Step 1 is subjected to rapid hot pressing sintering to obtain an interstitial element-doped high-entropy alloy billet. Step 3, Rolling: The interstitial element-doped high-entropy alloy billet obtained in Step 2 is subjected to hot rolling and cold rolling in sequence to obtain interstitial element-doped high-entropy alloy sheet. Step 4, Heat Treatment: The interstitial element-doped high-entropy alloy plate obtained in Step 3 is subjected to annealing heat treatment to obtain a high-temperature resistant nuclear interstitial element-doped high-entropy alloy material.

[0010] This invention ensures the uniformity of high-entropy alloy composition through mechanical alloying and sintering. At the same time, interstitial elements are introduced, and the material microstructure is optimized through subsequent rolling and heat treatment processes to obtain a good match between room temperature and high temperature strength and plasticity. This results in a high-temperature resistant nuclear interstitial element-doped high-entropy alloy material, which is suitable for key structural components such as high-temperature nuclear reactor shells.

[0011] The above method is characterized in that the ceramic powder containing interstitial elements O, B, or N in step one is TiO2, TiB2, or TiN, respectively. This invention prevents the introduction of impurities by using TiO2, TiB2, or TiN to introduce elements O, B, or N.

[0012] The method described above is characterized in that the average particle size of the elemental metal powder and ceramic powder in step one is 5μm to 100μm. This invention improves flowability by controlling the particle size of the elemental metal powder and ceramic powder, thus ensuring the quality of sintering and forming. It prevents the powder from being too small, making it difficult to flow and uniformly fill complex corners of the mold, thus affecting material forming. It also prevents the powder from being too large, resulting in more pores and making the material difficult to densify, thus affecting performance.

[0013] The above method is characterized in that the rotation speed of the ball mill mechanical alloying in step one is 100 r / min to 500 r / min, and the time is 24 h to 72 h. This invention first achieves atomic-level mixing and alloying of elemental metal powder and ceramic powder providing interstitial elements during high-energy ball milling by mechanical alloying and controlling its parameters. This directly prepares a high-entropy alloy powder with uniform composition and containing interstitial atoms, avoiding the problems of easy burn-off of interstitial elements and difficulty in precise composition control in the smelting method.

[0014] The above method is characterized in that, in step two, the rapid hot-pressing sintering involves a heating rate of 50℃ / min to 500℃ / min, a temperature of 800℃ to 1300℃, a pressure of 10MPa to 50MPa, and a holding time of 30min. This invention employs rapid hot-pressing sintering technology to densify under high heating rates and pressures, effectively suppressing excessive grain growth during sintering, resulting in a dense, fine-grained ingot, and laying the foundation for subsequent deformation processing.

[0015] The above method is characterized in that the hot rolling temperature in step three is 700℃~1000℃, the single rolling amount is 8%~20%, and the total rolling amount is 30%~50%. This invention utilizes a combined hot and cold rolling process, with hot rolling aiming to break down the as-cast structure and improve machinability.

[0016] The method described above is characterized in that, in step three, the single rolling depth of cold rolling is 5% to 15%, and the total rolling depth is 70% to 90%. This invention utilizes a composite rolling process of hot rolling and cold rolling, where cold rolling introduces high-density dislocations and deformation energy storage, significantly refining grains and improving strength.

[0017] The above method is characterized in that the annealing heat treatment in step four is carried out at a temperature of 600℃~1100℃ for 5min~120min, and the cooling method after annealing heat treatment is water quenching or furnace cooling. This invention, by controlling the parameters of the annealing heat treatment and the cooling method, regulates the degree of recrystallization of the alloy, the morphology and distribution of precipitated phases, and releases some internal stress, thereby restoring or improving the plasticity of the material while maintaining high strength, resulting in a final product with excellent comprehensive performance.

[0018] Compared with the prior art, the present invention has the following advantages: 1. Stable microstructure: This invention introduces O, B, or N interstitial elements into the Ti-V-Cr-Al-Zr high-entropy alloy system. These elements occupy interstitial positions in the alloy and, through strong lattice distortion effects and interactions with principal metal atoms, effectively hinder atomic diffusion and dislocation movement. This stabilizes the single-phase solid solution structure of the high-entropy alloy, suppresses the precipitation of brittle intermetallic compound phases at high temperatures, and improves the thermal stability of the high-entropy alloy material doped with interstitial elements.

[0019] 2. Optimized mechanical properties: This invention employs a preparation process that combines mechanical alloying, rapid hot pressing sintering, multi-pass rolling, and final annealing heat treatment. This process achieves precise control over the microstructure of the material. It not only yields a completely dense material but also significantly refines the grain size to the submicron or even nanometer level. At the same time, it introduces a high-density dislocation network. The combined effect of grain refinement and dislocation strengthening greatly improves the high-temperature strength of the high-entropy alloy material doped with interstitial elements.

[0020] 3. Enhanced strength-plasticity matching: The final heat treatment step of this invention controls the degree of recrystallization to restore the plasticity of the material while maintaining high strength. The fine grains and uniform structure promote the cross-slip of dislocations and avoid stress concentration, thereby improving the plastic deformation capacity and fracture toughness of the material and achieving excellent high-temperature strength-plasticity matching.

[0021] 4. Strong applicability: The Ti, V, Cr, Al and Zr selected in this invention are all elements with low activation or small neutron absorption cross sections. The high-entropy alloy itself has good radiation resistance potential. The high-temperature mechanical properties obtained through interstitial element doping and process optimization make this nuclear interstitial element doped high-entropy alloy material very suitable for manufacturing key components such as the shell, pipes and core structural parts of new high-temperature nuclear reactors.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a transmission electron microscope image of the interstitial oxygen-doped high-entropy alloy material prepared in Example 1 of the present invention.

[0024] Figure 2 The table shows the room temperature and high temperature tensile stress-strain curves of the interstitial oxygen-doped high-entropy alloy material prepared in Example 1 of this invention.

[0025] Figure 3 The figure shows the room temperature and high temperature tensile stress-strain curves of the high-entropy alloy prepared in Comparative Example 1 of this invention. Detailed Implementation

[0026] Example 1 In this embodiment, the interstitial element-doped high-entropy alloy material used for the nuclear component is (Ti). 30 V 25 Cr 20 Al 15 Zr 9.5 )O 0.5 .

[0027] This embodiment includes the following steps: Step 1, Mechanical alloying: Weigh elemental metal powders of Ti, V, Cr, Al and Zr with an average particle size of 50 μm, as well as TiO2 ceramic powder, and mix them according to the molar ratio of the target alloy composition. Then pour them into a high-energy ball mill jar and ball mill them at a speed of 300 r / min for 48 h under argon protection to obtain alloyed interstitial oxygen element doped high-entropy alloy powder. Step 2, sintering and forming: The interstitial oxygen element doped high-entropy alloy powder obtained in Step 1 is loaded into a graphite mold, heated to 1100℃ at a rate of 100℃ / min in a vacuum rapid hot pressing sintering furnace, and a pressure of 40MPa is applied. The holding time is 30min to obtain a dense interstitial oxygen element doped high-entropy alloy billet. Step 3, Rolling: After grinding the surface of the interstitial oxygen element doped high-entropy alloy billet obtained in Step 2, it is hot rolled in multiple passes at 850℃, with a single rolling amount of 12% and a total hot rolling amount of 40%. Then, it is cold rolled in multiple passes, with a single rolling amount of 10% and a total cold rolling amount of 85%, to obtain interstitial oxygen element doped high-entropy alloy sheet. Step 4, Heat treatment: The interstitial oxygen element doped high-entropy alloy plate obtained in Step 3 is annealed at 900℃ and held for 30 minutes, followed by water quenching to obtain the nuclear interstitial oxygen element doped high-entropy alloy material.

[0028] Figure 1 This is a transmission electron microscope image of the interstitial oxygen-doped high-entropy alloy material prepared in this embodiment. Figure 1 As can be seen from the above, the interstitial oxygen-doped high-entropy alloy material prepared in this embodiment exhibits multiple intersecting dislocation slip bands. When subjected to stress, the movement of the dislocation slip bands in the interstitial oxygen-doped high-entropy alloy material can prevent stress concentration, thereby improving strength and plasticity.

[0029] Figure 2 The table shows the room temperature and high temperature tensile stress-strain curves of the interstitial oxygen-doped high-entropy alloy material prepared in this embodiment. Figure 2 As can be seen from the data, the high-entropy alloy material doped with interstitial oxygen element for nuclear applications prepared in this embodiment has a tensile strength, yield strength, and elongation of 1049 MPa, 1124 MPa, and 21% at 25℃, a tensile strength, yield strength, and elongation of 938 MPa, 1208 MPa, and 26% at 400℃, and a tensile strength, yield strength, and elongation of 712 MPa, 840 MPa, and 32% at 600℃. This indicates that the high-entropy alloy material doped with interstitial oxygen element for nuclear applications has excellent room temperature and high temperature strength and plasticity.

[0030] Comparative Example 1 The high-entropy alloy material used in this comparative example is Ti. 30 V 25 Cr 20 Al 15 Zr 9.5 .

[0031] This comparative example includes the following steps: Step 1, Mechanical alloying: Weigh elemental metal powders of Ti, V, Cr, Al and Zr with an average particle size of 50 μm, mix them according to the molar ratio of the target alloy composition, and then pour them into a high-energy ball mill jar. Under argon protection, ball mill at a speed of 300 r / min for a total of 48 h to obtain alloyed high-entropy alloy powder. Step 2, sintering and forming: The high-entropy alloy powder obtained in Step 1 is loaded into a graphite mold, heated to 1100°C at a rate of 100°C / min in a rapid hot pressing sintering furnace, and a pressure of 40MPa is applied. The holding time is 30min to obtain a dense high-entropy alloy billet. Step 3, Rolling: After grinding the surface of the high-entropy alloy billet obtained in Step 2, it is hot rolled in multiple passes at 850℃, with a single rolling amount of 12% and a total hot rolling amount of 40%. Then, it is cold rolled in multiple passes, with a single rolling amount of 10% and a total cold rolling amount of 85%, to obtain the high-entropy alloy sheet. Step 4, Heat treatment: The high-entropy alloy plate obtained in step 3 is annealed at 900℃ and held for 30 minutes, followed by water quenching to obtain a high-entropy alloy material doped with interstitial oxygen element for nuclear use.

[0032] Figure 3 The room temperature and high temperature tensile stress-strain curves of the high-entropy alloy prepared in this comparative example are shown below. Figure 2 As can be seen, the high-entropy alloy has tensile strength, yield strength, and elongation of 964 MPa, 970 MPa, and 23% at 25℃, 780 MPa, 994 MPa, and 25% at 400℃, and 624 MPa, 790 MPa, and 24% at 600℃.

[0033] The yield strength, ultimate strength, and elongation of the high-entropy alloy prepared in Comparative Example 1 and the interstitial oxygen-doped high-entropy alloy prepared in Example 1 under conditions of 25℃, 400℃, and 600℃ are recorded in Table 1. It can be clearly seen from Table 1 that the high-entropy alloy in Example 1 with interstitial oxygen doping has significantly improved mechanical properties at room temperature and high temperature compared with the high-entropy alloy in the Comparative Example without interstitial oxygen doping.

[0034] Table 1

[0035] Example 2 In this embodiment, the interstitial element-doped high-entropy alloy material used for the nuclear component is (Ti). 40 V 15 Cr 10 Al 25 Zr5)B5.

[0036] This embodiment includes the following steps: Step 1, Mechanical alloying: Weigh elemental metal powders of Ti, V, Cr, Al and Zr with an average particle size of 100 μm, as well as TiB2 ceramic powder, and mix them according to the molar ratio of the target alloy composition. Then pour them into a high-energy ball mill jar and ball mill them for a total of 72 h at a speed of 100 r / min under argon protection. Pause for 10 min every 1 h of ball milling to obtain alloyed interstitial boron doped high-entropy alloy powder. Step 2, sintering and forming: The interstitial boron-doped high-entropy alloy powder obtained in Step 1 is loaded into a graphite mold, heated to 1300℃ at a rate of 500℃ / min in a vacuum rapid hot pressing sintering furnace, and a pressure of 10MPa is applied. The holding time is 30min to obtain a dense interstitial boron-doped high-entropy alloy billet. Step 3, Rolling: After grinding the surface of the high-entropy alloy billet obtained in Step 2, it is hot rolled in multiple passes at 1000℃, with a single rolling amount of 20% and a total hot rolling amount of 50%. Then, it is cold rolled in multiple passes, with a single rolling amount of 5% and a total cold rolling amount of 90%, to obtain the high-entropy alloy sheet with interstitial boron doping. Step 4, Heat treatment: The interstitial boron-doped high-entropy alloy plate obtained in Step 3 is annealed at 1100℃ and held for 5 minutes, then cooled in the furnace to obtain the interstitial boron-doped high-entropy alloy material for nuclear applications.

[0037] Testing revealed that the high-entropy interstitial boron-doped alloy material prepared in this embodiment exhibited tensile strength, yield strength, and elongation of 1038 MPa, 1045 MPa, and 24% at 25°C; tensile strength, yield strength, and elongation of 855 MPa, 1025 MPa, and 26% at 400°C; and tensile strength, yield strength, and elongation of 698 MPa, 862 MPa, and 31% at 600°C. These results demonstrate that the high-entropy interstitial boron-doped alloy material possesses excellent room-temperature and high-temperature strength and ductility.

[0038] Example 3 In this embodiment, the interstitial element-doped high-entropy alloy material used for the nuclear component is (Ti). 20 V 24.9 Cr 25 Al 10 Zr 20 )N 0.1 .

[0039] This embodiment includes the following steps: Step 1, Mechanical alloying: Weigh elemental metal powders of Ti, V, Cr, Al and Zr with an average particle size of 5 μm, as well as TiN ceramic powder, and mix them according to the molar ratio of the target alloy composition. Then pour them into a high-energy ball mill jar and ball mill them for 24 hours at a speed of 500 r / min under argon protection to obtain alloyed interstitial nitrogen-doped high-entropy alloy powder. Step 2, sintering and forming: The interstitial nitrogen-doped high-entropy alloy powder obtained in Step 1 is loaded into a graphite mold, heated to 800°C at a rate of 50°C / min in a vacuum rapid hot pressing sintering furnace, and a pressure of 50MPa is applied. The holding time is 30min to obtain a dense interstitial nitrogen-doped high-entropy alloy billet. Step 3, Rolling: After grinding the surface of the interstitial nitrogen-doped high-entropy alloy billet obtained in Step 2, it is hot rolled at 700℃ in multiple passes with a single rolling amount of 8% and a total hot rolling amount of 30%. Then, it is cold rolled in multiple passes with a single rolling amount of 15% and a total cold rolling amount of 70% to obtain interstitial nitrogen-doped high-entropy alloy sheet. Step 4, Heat treatment: The interstitial nitrogen-doped high-entropy alloy plate obtained in Step 3 is annealed at 700℃ and held for 100 min, and then cooled in the furnace to obtain the interstitial nitrogen-doped high-entropy alloy material for nuclear applications.

[0040] Testing revealed that the interstitial nitrogen-doped high-entropy alloy material prepared in this embodiment exhibited tensile strength, yield strength, and elongation of 1043 MPa, 1050 MPa, and 28% at 25°C, 860 MPa, 1075 MPa, and 30% at 400°C, and 703 MPa, 867 MPa, and 29% at 600°C. This demonstrates that the interstitial nitrogen-doped high-entropy alloy material possesses excellent room-temperature and high-temperature strength and ductility.

[0041] Example 4 In this embodiment, the interstitial element-doped high-entropy alloy material used for the nuclear component is (Ti). 25 V 30 Cr 15 Al 20 Zr9)O1.

[0042] This embodiment includes the following steps: Step 1, Mechanical alloying: Weigh elemental metal powders of Ti, V, Cr, Al and Zr with an average particle size of 30 μm, as well as TiO2 ceramic powder, and mix them according to the molar ratio of the target alloy composition. Then pour them into a high-energy ball mill jar and ball mill them for 60 h at a speed of 200 r / min under argon protection to obtain alloyed interstitial oxygen element doped high-entropy alloy powder. Step 2, sintering and forming: The interstitial oxygen element doped high-entropy alloy powder obtained in Step 1 is loaded into a graphite mold, heated to 1000℃ at a rate of 150℃ / min in a vacuum rapid hot pressing sintering furnace, and a pressure of 30MPa is applied. The holding time is 30min to obtain a dense interstitial oxygen element doped high-entropy alloy billet. Step 3, Rolling: After grinding the surface of the interstitial oxygen element doped high-entropy alloy billet obtained in Step 2, it is hot rolled in multiple passes at 800℃, with a single rolling amount of 10% and a total hot rolling amount of 35%. Then, it is cold rolled in multiple passes, with a single rolling amount of 8% and a total cold rolling amount of 80%, to obtain interstitial oxygen element doped high-entropy alloy sheet. Step 4, Heat treatment: The interstitial oxygen element doped high-entropy alloy plate obtained in Step 3 is annealed at 600℃ and held for 120 minutes, followed by water quenching to obtain the nuclear interstitial oxygen element doped high-entropy alloy material.

[0043] Testing revealed that the nuclear interstitial oxygen-doped high-entropy alloy material prepared in this embodiment exhibited tensile strength, yield strength, and elongation of 1049 MPa, 1058 MPa, and 26% at 25°C; tensile strength, yield strength, and elongation of 865 MPa, 1081 MPa, and 32% at 400°C; and tensile strength, yield strength, and elongation of 710 MPa, 862 MPa, and 31% at 600°C. This demonstrates that the nuclear interstitial oxygen-doped high-entropy alloy material possesses excellent room-temperature and high-temperature strength and ductility.

[0044] Example 5 In this embodiment, the interstitial element-doped high-entropy alloy material used for the nuclear component is (Ti). 35 V 20 Cr 15 Al 12 Zr 15 )O3.

[0045] This embodiment includes the following steps: Step 1, Mechanical alloying: Weigh elemental metal powders of Ti, V, Cr, Al and Zr with an average particle size of 70 μm, as well as TiO2 ceramic powder, and mix them according to the molar ratio of the target alloy composition. Then pour them into a high-energy ball mill jar and ball mill them for 30 hours at a speed of 400 r / min under argon protection to obtain alloyed interstitial oxygen element doped high-entropy alloy powder. Step 2, sintering and forming: The interstitial oxygen element doped high-entropy alloy powder obtained in Step 1 is loaded into a graphite mold, heated to 900°C at a rate of 80°C / min in a vacuum rapid hot pressing sintering furnace, and a pressure of 20MPa is applied. The holding time is 30min to obtain a dense interstitial oxygen element doped high-entropy alloy billet. Step 3, Rolling: After grinding the surface of the interstitial oxygen element doped high-entropy alloy billet obtained in Step 2, it is hot rolled at 900℃ in multiple passes with a single rolling amount of 15% and a total hot rolling amount of 45%. Then, it is cold rolled in multiple passes with a single rolling amount of 12% and a total cold rolling amount of 75% to obtain interstitial oxygen element doped high-entropy alloy sheet. Step 4, Heat treatment: The interstitial oxygen element doped high-entropy alloy plate obtained in Step 3 is annealed at 1000℃ and held for 30 minutes, followed by water quenching to obtain the nuclear interstitial oxygen element doped high-entropy alloy material.

[0046] Testing revealed that the interstitial nitrogen-doped high-entropy alloy material prepared in this embodiment exhibited tensile strength, yield strength, and elongation of 1053 MPa, 1090 MPa, and 27% at 25°C, 870 MPa, 1155 MPa, and 31% at 400°C, and 715 MPa, 880 MPa, and 34% at 600°C. This demonstrates that the interstitial nitrogen-doped high-entropy alloy material possesses excellent room-temperature and high-temperature strength and ductility.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A high-entropy alloy material doped with interstitial elements for nuclear applications, characterized in that, This high-entropy alloy material is denoted as (Ti) according to the molar ratio of its constituent elements. a V b Cr c Al d Zr e )X f X is selected from one of the interstitial elements O, B and N, and satisfies: 20≤a≤40, 15≤b≤30, 10≤c≤25, 10≤d≤25, 5≤e≤20, 0.1≤f≤5, and a+b+c+d+e+f=100.

2. A method for preparing a high-entropy alloy material doped with interstitial elements for nuclear applications as described in claim 1, characterized in that, The method includes the following steps: Step 1, Mechanical alloying: Pour elemental metal powders of Ti, V, Cr, Al and Zr and ceramic powders containing interstitial elements O, B or N into a ball mill jar for ball milling and mechanical alloying to obtain interstitial element-doped high-entropy alloy powder. Step 2, Sintering and Shaping: The interstitial element-doped high-entropy alloy powder obtained in Step 1 is subjected to rapid hot pressing sintering to obtain an interstitial element-doped high-entropy alloy billet. Step 3, Rolling: The interstitial element-doped high-entropy alloy billet obtained in Step 2 is subjected to hot rolling and cold rolling in sequence to obtain interstitial element-doped high-entropy alloy sheet. Step 4, Heat Treatment: The interstitial element-doped high-entropy alloy plate obtained in Step 3 is subjected to annealing heat treatment to obtain a high-temperature resistant nuclear interstitial element-doped high-entropy alloy material.

3. The method according to claim 2, characterized in that, The ceramic powder containing interstitial elements O, B, or N mentioned in step one is TiO2, TiB2, or TiN, respectively.

4. The method according to claim 2, characterized in that, The average particle size of the elemental metal powder and ceramic powder mentioned in step one is 5μm~100μm.

5. The method according to claim 2, characterized in that, The rotational speed of the ball mill mechanical alloying in step one is 100 r / min to 500 r / min, and the time is 24 h to 72 h.

6. The method according to claim 2, characterized in that, The rapid hot pressing sintering process described in step two involves a heating rate of 50℃ / min to 500℃ / min, a temperature of 800℃ to 1300℃, a pressure of 10MPa to 50MPa, and a holding time of 30min.

7. The method according to claim 2, characterized in that, The hot rolling temperature in step three is 700℃~1000℃, the single rolling amount is 8%~20%, and the total rolling amount is 30%~50%.

8. The method according to claim 2, characterized in that, In step three, the single rolling amount of cold rolling is 5% to 15%, and the total rolling amount is 70% to 90%.

9. The method according to claim 2, characterized in that, The annealing heat treatment in step four is performed at a temperature of 600℃~1100℃ for 5min~120min, and the cooling method after annealing heat treatment is water quenching or furnace cooling.

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