A tungsten-based solid solution alloy and a preparation method and application thereof

Abstract

This invention relates to the field of solid solution alloy technology, specifically disclosing a tungsten-based solid solution alloy, its preparation method, and its applications. The tungsten-based solid solution alloy includes a matrix and alloying elements dissolved in the matrix, wherein the matrix is ​​metallic tungsten; and the alloying elements include hafnium, tantalum, and boron. This invention utilizes the homogeneity, low melting point, and strong capillary diffusion ability of the Hf-Ta-B amorphous alloy to pre-prepare its amorphous powder, which is then mixed with pure W powder to form the target alloy. The raw material powders are uniformly mixed by ball milling, and then the W-based solid solution alloy sintered body is prepared using conventional hot pressing sintering technology at a certain sintering temperature (slightly higher than the melting point of the Hf-Ta-B amorphous alloy). Finally, high-energy-rate forging further optimizes the composite solid solution strengthening of Hf and Ta, as well as the grain-refining strengthening effect of B, ultimately obtaining a fine-grained W-based rare-grain solid solution alloy with good composition and microstructure homogeneity, resulting in an alloy with both high thermal conductivity and excellent high-temperature mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of solid solution alloy technology, specifically to a tungsten-based solid solution alloy, its preparation method, and its applications. Background Technology

[0002] Tungsten (W) has the highest melting point of all metals, the second highest Young's modulus after osmium (Os), high high-temperature strength, and special properties such as high thermal conductivity, low physical sputtering rate, low tritium retention, and low neutron activation. It is widely used in engineering fields such as lighting, aerospace, electronic packaging, military equipment, and nuclear energy.

[0003] In future magnetic confinement fusion reactors, advanced W alloys are the primary materials for plasma-oriented components. During fusion reactor operation, W alloys need to withstand the high thermal loads caused by high-flux edge plasmas. Under immense thermal stress, they are prone to cracking, making high-temperature strength a critical performance indicator. On the other hand, W alloys must have high thermal conductivity to ensure rapid heat transfer to heat sink materials, preventing recrystallization or even surface melting. Therefore, high-temperature strength and thermal conductivity are two key properties for advanced W alloys used as high-heat-flux materials in fusion reactors.

[0004] Pure W has a high ductile-brittle transition temperature and a low recrystallization temperature, and its high-temperature strength and resistance to high-temperature creep are insufficient, making it difficult to meet the service performance requirements of plasma-oriented materials. Generally, W-based solid solution alloys have good high-temperature structural stability, and solid solution strengthening is an important way to improve the high-temperature performance of W materials. However, neutron activation limits the application of elements such as Nb, Mo, Ni, and Co as solid solution components; while low-neutron-activated solid solution elements such as Zr and Ti are beneficial to improving the strength of W, they also increase the ductile-brittle transition temperature of the material, thus severely restricting the processing of components. Among industrial W alloys, only W-Re alloys with high rhenium content (5 wt.%) have room-temperature plasticity; however, the transmutation of Re in the service environment causes severe helium embrittlement, prohibiting their use in fusion reactors. In particular, excessive addition of alloying elements such as Re causes a sharp decrease in the thermal conductivity of the material, severely limiting the application of W-Re and other solid solution alloys as high heat flux materials in fusion reactors.

[0005] To obtain tungsten-based solid solution alloys with high thermal conductivity and good high-temperature strength, the total content of solid solution elements must be strictly controlled (generally below 5 wt.%). Therefore, we need to select low-neutron-activating additives with good solid solution strengthening effects; simultaneously, we need to ensure that the low content of additives can be uniformly dissolved into the W matrix during the preparation process, and avoid grain coarsening caused by related processes.

[0006] Studies have shown that hafnium (Hf) has a significant solid solution strengthening effect on W materials, superior to tantalum (Ta) and re. Among the three solid solution elements mentioned above, Hf differs from W in atomic radius, lattice parameters, melting point, and density, and therefore has the lowest solid solubility in W (4 at.%, 800℃~9 at.%, 2512℃), far lower than re (~30 at.%, 800℃~45 at.%, 2890℃) and Ta (infinitely miscible).

[0007] Recently, Liu Shasha (Influence of Hf Microalloying on the Microstructure and Properties of Tungsten-based Plasma-oriented Materials. Southwestern Institute of Physics, Nuclear Industry. 2020 Master's Thesis) prepared a W-Hf alloy with Hf (1.0 wt.% Hf) by combining spark plasma sintering (1850℃, 3 min, 90 MPa, small sample) and hydrogen sintering (~2300℃, large sample) with high energy rate forging technology. The test results showed that the Hf in the alloy mainly combined with O in the W matrix to form HfO2, which purified the grain boundary impurities of the W matrix, improved the low-temperature plasticity of the material, and increased the recrystallization temperature of the W material.

[0008] It must be pointed out that in W-Hf alloys with low Hf content prepared by current technologies, Hf is mainly distributed in the form of HfO2 oxide at the grain boundaries of the W matrix, and the addition of Hf has not been fully dissolved in the W matrix. This fact fully illustrates that it is very challenging to uniformly dissolve low-content Hf into the W matrix. At the same time, most existing W-Hf alloy preparation technologies are only suitable for the preparation of small-sized research samples and cannot meet the needs of preparing large-sized practical material samples; while hydrogen sintering can achieve the preparation of large-sized W materials, its sintering temperature is generally above 2100℃, which easily leads to grain coarsening of the W material. Summary of the Invention

[0009] The purpose of this invention is to provide a tungsten-based solid solution alloy that has both high thermal conductivity and excellent high-temperature mechanical properties, which can meet the performance requirements in nuclear fusion.

[0010] Furthermore, this invention also provides a method for preparing the above-mentioned tungsten-based solid solution alloy and its application; the method described in this invention not only successfully prepares hafnium-containing single-phase tungsten-based rare solid solution alloys, but also significantly reduces the sintering temperature and holding time of tungsten materials, ultimately enabling the prepared tungsten-based solid solution alloy to possess both high thermal conductivity and excellent high-temperature mechanical properties.

[0011] This invention is achieved through the following technical solution:

[0012] A tungsten-based solid solution alloy includes a matrix and alloying elements dissolved in the matrix, wherein the matrix is ​​metallic tungsten; and the alloying elements include hafnium, tantalum, and boron.

[0013] The tungsten-based solid solution alloy of this invention is a single-phase solid solution alloy. The tungsten-based solid solution alloy has alloying elements (hafnium, tantalum and boron) uniformly dissolved in a metallic tungsten matrix, realizing composite solid solution strengthening of Hf and Ta elements. By introducing B element, the grain coarsening problem during the sintering of W material is overcome, the fine grain strengthening effect is improved, and the grain coarsening problem caused by excessively high sintering temperature in the existing method of preparing large-size W material by hydrogen sintering is avoided.

[0014] The alloying elements (hafnium, tantalum, and boron) used in this invention possess the characteristics of homogeneity, low melting point, and strong capillary diffusion ability in amorphous alloys. They can be pre-prepared as amorphous powders and then used to prepare tungsten-based solid solution alloys through conventional hot pressing sintering technology. This can achieve sufficient solid solution of Hf in the matrix W, effectively solving the problem that existing low-Hf W-Hf alloys mainly have Hf distributed in the form of HfO2 oxide at the grain boundaries of the W matrix particles, and fail to achieve sufficient solid solution of the added element Hf in the matrix W.

[0015] Experiments have shown that the tungsten-based solid solution alloy described in this invention possesses both high thermal conductivity and excellent high-temperature mechanical properties, which can meet the performance requirements in nuclear fusion.

[0016] Furthermore, the chemical composition of the tungsten-based solid solution alloy, by weight percentage, is W 100-a (Hf,Ta,B) a Where 1≤a≤3.

[0017] That is, the weight percentage of W and alloying elements (a mixture of Hf, Ta and B) in the tungsten-based solid solution alloy of the present invention is (100-a):a.

[0018] The present invention limits the value of 'a' because the performance of W-based solid solution alloys will decrease if the value exceeds this range. If 'a' is less than 1, the performance of W-based solid solution alloys cannot be effectively improved due to insufficient addition of alloying elements. If 'a' is greater than 3, some brittle phases will be formed in the W-based solid solution alloys, resulting in a decrease in the performance of W-based solid solution alloys.

[0019] Furthermore, the chemical formulas of hafnium, tantalum, and boron, by weight percentage, are (Hf 100-b Ta b ) 98.5 B 1.5 Where 10≤b≤70.

[0020] That is, in the alloying elements, the weight percentage of Hf and Ta mixture to B is 98.5:1.5; and in the Hf and Ta mixture, the weight percentage of Hf and Ta is (100-b):b.

[0021] The limitation on the value of b in this invention is based on the selection when a is at a high value in the range [1,3]. When the value of a is too large, the mass proportion of the solid solution element is large, and the mass ratio of Ta to Hf is also large. Ta can be infinitely dissolved in tungsten, and an excessively high mass proportion will lead to a decrease in the plastic deformation ability of tungsten alloys. Therefore, it is necessary to limit the mass proportion of Ta in W-based solid solutions (i.e., the value of b).

[0022] A method for preparing tungsten-based solid solution alloys includes the following steps:

[0023] S1. Amorphous powders containing alloying elements are prepared by combining electric arc melting with melt atomization technology;

[0024] S2. The amorphous powder prepared in step S1 is ball-milled and mixed with tungsten powder to form a mixture.

[0025] S3. Prepare an alloy sintered body by hot pressing and sintering the mixture obtained in step S2;

[0026] S4. The alloy sintered body obtained in step S3 is subjected to high-energy-rate forging treatment.

[0027] This invention utilizes the homogeneity, low melting point, and strong capillary diffusion ability of Hf-Ta-B amorphous alloys. Amorphous powder is pre-prepared and mixed with pure W powder to form the target alloy. The raw material powders are then uniformly mixed using ball milling. A W-based solid solution alloy sintered body is prepared using conventional hot pressing sintering technology at a specific sintering temperature (slightly above the melting point of Hf-Ta-B amorphous alloys). Finally, high-energy-rate forging further optimizes the composite solid solution strengthening of Hf and Ta, as well as the grain-refining strengthening effect of B, ultimately obtaining a fine-grained W-based rare-grain solid solution alloy with good composition and microstructure homogeneity. This alloy possesses both high thermal conductivity and excellent high-temperature mechanical properties.

[0028] Further, step S1 includes the following steps:

[0029] S11. After mixing the alloying elements, place them in a non-consumable arc melting furnace and introduce argon gas to prepare alloy ingots through non-consumable arc melting.

[0030] S12. After crushing the alloy ingot prepared in step S11, atomize it to obtain amorphous powder.

[0031] Furthermore, during non-consumable arc melting, the working current is 200–250 A; the atomization powder production process is as follows:

[0032] After the alloy ingot is crushed, it is placed in a graphite crucible and heated to a temperature higher than the melting point of the alloying elements. The temperature is held for 2 to 5 minutes. Then, the molten alloying elements are sprayed out and cooled using atomization technology to obtain spherical powder material.

[0033] Furthermore, in step S2, the ball-to-material ratio of the ball mill mixture is 1:5 to 1:10, the ball milling time is 2 to 5 hours, and the ball mill speed is 150 to 200 rpm.

[0034] Furthermore, in step S3, the preload pressure for hot pressing sintering is 30 MPa, and the vacuum degree is 1 × 10⁻⁶. -2 Pa, sintering temperature is 1750-1850℃, sintering pressure is 70MPa, and holding time is 60-180min.

[0035] Furthermore, in step S4, the specific processing procedure for the high-energy-rate forging treatment is as follows:

[0036] First, heat the sintered billet to 1600℃ and hold for 30 minutes. Then, quickly place it in a high-speed pneumatic forging hammer for forging. The forging pressure is 40MPa, and the forging direction is along the central axis of the cylindrical sintered billet.

[0037] Applications of tungsten-based solid solution alloys in magnetic confinement fusion reactors, including their use in the fabrication of plasma components.

[0038] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0039] 1. This invention successfully prepared a single-phase W-based rare solid solution alloy containing Hf; its thermal conductivity from room temperature to 600℃ is close to that of pure W material; the yield strength measured by uniaxial tensile test at 400℃ exceeds 1000MPa, the plasticity exceeds 10%, and the high-temperature mechanical properties are excellent. That is, the tungsten-based solid solution alloy of this invention has both high thermal conductivity and excellent high-temperature mechanical properties, which can meet the performance requirements in nuclear fusion.

[0040] 2. This invention achieves composite solid solution strengthening of Hf and Ta elements, and overcomes the grain coarsening problem during the sintering of W materials by introducing B element, thereby improving the fine grain strengthening effect.

[0041] 3. By introducing special amorphous powder, liquid-solid reaction sintering of W-based rare solid solution alloys was successfully achieved, which significantly reduced the sintering temperature and holding time of W materials and avoided the problem of high-temperature grain coarsening in W materials; providing a new approach to improve the material properties and production efficiency of W-based solid solution alloys. Attached Figure Description

[0042] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0043] Figure 1 The image shows the XRD pattern of the spherical powder material prepared in the first step of Example 1 of this invention.

[0044] Figure 2 The image shows the XRD pattern of the sintered body prepared in the second step of Example 1 of this invention.

[0045] Figure 3 This is a fracture grain size diagram of the sintered body prepared in the second step of Example 1 of the present invention;

[0046] Figure 4 The following are uniaxial tensile stress-strain curves of the solid solution alloy prepared in Example 1 of this invention at different temperatures;

[0047] Figure 5 The image shows the XRD pattern of the spherical powder material prepared in the first step of Example 2 of this invention.

[0048] Figure 6 The image shows the XRD pattern of the sintered body prepared in the second step of Example 2 of this invention.

[0049] Figure 7 This is a fracture grain size diagram of the sintered body prepared in the second step of Example 2 of the present invention;

[0050] Figure 8 The images show the uniaxial tensile stress-strain curves of the solid solution alloy prepared in Example 2 of this invention at different temperatures; the red curve is covered by the blue curve, and the endpoint of the red curve is represented by a red triangle.

[0051] Figure 9 The image shows the XRD pattern of the spherical powder material prepared in the first step of Example 3 of this invention.

[0052] Figure 10 The image shows the XRD pattern of the sintered body prepared in the second step of Example 3 of this invention.

[0053] Figure 11 This is a fracture grain size diagram of the sintered body prepared in the second step of Example 3 of the present invention;

[0054] Figure 12 The uniaxial tensile stress-strain curves of the solid solution alloy prepared in Example 3 of the present invention at different temperatures. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0056] The existing techniques for preparing W alloys containing Hf have the following drawbacks: (1) no successful single-phase dilute solid solution alloys based on W with trace amounts of added Hf have been obtained; (2) all are solid-phase sintering, which makes it impossible for Hf to be fully and uniformly dissolved into the W matrix during sintering, and it is easy for Hf to segregate at the grain boundaries and induce the formation of HfO2 oxide, thus failing to achieve the solid solution strengthening effect of low Hf content; (3) the sintering temperature of large-size samples is generally higher than 2100℃, which easily leads to coarsening of W grains in the matrix.

[0057] To address the aforementioned problems, this embodiment provides a W-based rare-state solid solution alloy containing Hf, exhibiting both high thermal conductivity and excellent high-temperature mechanical properties, and its preparation method. The alloy is a single-phase solid solution with a 1-5m scale polycrystalline W as the matrix, comprising the matrix metal W and alloying elements Hf, Ta, and B. The chemical composition formula of the alloy is W. 100-a (Hf,Ta,B) a Where 1≤a≤3 represents the weight percentage of the components.

[0058] A method for preparing a W-based alloy containing Hf rare solid solution, exhibiting both high thermal conductivity and excellent high-temperature mechanical properties, firstly involves preparing a W-based alloy with a melting point below 1900℃ using arc melting combined with melt atomization technology. 100-b Ta b ) 98.5 B 1.5 (10≤b≤70, weight percentage) Amorphous powder; after sieving, it is mixed with commercially available high-purity W powder as raw material, and the mixture is formulated based on the nominal composition of the target W-based rare solid solution alloy. After being ball-milled and mixed evenly, it is placed in a sintering furnace and prepared by hot pressing sintering technology. 100-a (Hf,Ta,B) a Alloy sintered body; finally, the prepared sintered body is subjected to high-energy-rate forging treatment.

[0059] Example 1:

[0060] A tungsten-based solid solution alloy comprises a matrix and alloying elements dissolved in the matrix, wherein the matrix is ​​metallic tungsten; and the alloying elements include hafnium, tantalum, and boron. The chemical formula of the tungsten-based solid solution alloy is W. 98.48 Hf 0.5 Ta1B 0.02 .

[0061] W 98.48 Hf 0.5 Ta1B 0.02 The preparation process of solid solution alloys is as follows:

[0062] (1) The first step is to prepare (Hf) 33.3 Ta 66.7 ) 98.5 B 1.5 Amorphous powder

[0063] First, using industrial-grade pure Hf (>99%), Ta (>99.5%), and B (>99%) as raw materials, a mixture with a weight percentage composition of (Hf) was prepared. 33.3 Ta 66.7 ) 98.5 B 1.5 The alloy was placed in a water-cooled copper crucible in a non-consumable arc furnace and evacuated to a vacuum of 5 × 10⁻⁶. -2 Pa, and 0.02 MPa of industrial pure Ar gas is introduced for non-consumable arc melting, with a melting working current of 250 A; the alloy is repeatedly melted by turning it upside down 3 times to obtain an alloy ingot with uniform composition.

[0064] (Hf) 33.3 Ta 66.7 ) 98.5 B 1.5 The alloy ingot was crushed and placed in a graphite crucible for atomization powder preparation: it was heated to 1800℃ (above the melting point of the alloy ingot) by medium-frequency induction heating and held for 3 minutes. The powder was then sprayed out and cooled using atomization technology (atomizing gas pressure of 5 MPa, guide rod nozzle orifice diameter of 1 mm) to obtain spherical powder material with a particle size between 5 and 20 μm, which was then sieved and set aside. X-ray diffraction (XRD) results are shown below. Figure 1 As shown, this indicates that the powder has an amorphous structure.

[0065] (2) The second step is to prepare W 98.48 Hf 0.5 Ta1B 0.02 solid solution dilute solid solution alloy

[0066] Using commercially available pure W powder (>99.9%) with a particle size of 2μm as the material matrix, and Hf with a particle size of 5-6.5μm... 33.3 Ta 66.7 ) 98.5 B 1.5 Amorphous powder (sieved using 2000-mesh and 5000-mesh sieves) was used as raw material, weighed, and formulated with a nominal composition of W. 98.48 [(Hf 33.3 Ta 66.7 ) 98.5 B 1.5 ] 1.52 (i.e. W) 98.48 Hf 0.5 Ta1B 0.02 Alloy. After mixing the powder raw materials, they were loaded into a ball mill jar together with grinding balls (material-to-ball ratio of 1:5) and subjected to high-energy ball milling in an argon atmosphere. The ball mill speed was 180 rpm and the ball milling time was 2 hours.

[0067] The thoroughly mixed powder raw materials were loaded into a vacuum hot-pressing sintering furnace for sintering to produce the target alloy sintered body. The preload pressure during sintering was 30 MPa, and the vacuum degree was 1 × 10⁻⁶. -2 The sintering temperature was 1800℃, the sintering pressure was 70MPa, and the holding time was 120min. The furnace was then cooled to room temperature, and the sintered sample was removed. The density of the sintered body was measured to be 95.8%. X-ray diffraction (XRD) results are as follows: Figure 2 As shown: This indicates that the sintered body has a single-phase BCC structure. Optical microscopy revealed that the average grain size of the sintered body is approximately 2 μm, and the grain size at the fracture surface is as follows. Figure 3 As shown.

[0068] Next, the sintered billet sample was heated to 1600℃ and held for 30 min. Then, it was rapidly placed in a high-speed pneumatic forging hammer for forging at a forging pressure of 40 MPa, with the forging direction along the central axis of the cylindrical sintered billet sample. Finally, the mechanical and thermal conductivity properties of the forged sample were tested. The results show that W 98.48 Hf 0.5 Ta1B 0.02 The thermal conductivity of the rare-saturated solid solution alloy from 30℃ to 600℃ is 176 W / (m·K)-30℃, 118 W / (m·K)-400℃, and 113 W / (m·K)-600℃, respectively, and the thermal conductivity is 159 W / (m·K)-30℃, 123 W / (m·K)-400℃, and 122 W / (m·K)-600℃, respectively, all exceeding 97% of the thermal conductivity of pure W under the same conditions; its uniaxial tensile test curves from room temperature to 400℃ are attached. Figure 4 As shown, its yield strength at 400℃ is close to 1100MPa, and its plasticity is over 10%, indicating good comprehensive high-temperature performance.

[0069] Example 2:

[0070] A tungsten-based solid solution alloy comprises a matrix and alloying elements dissolved in the matrix, wherein the matrix is ​​metallic tungsten; and the alloying elements include hafnium, tantalum, and boron. The chemical formula of the tungsten-based solid solution alloy is W. 99 Hf 0.887 Ta 0.098 B 0.015 .

[0071] W 99 Hf 0.887 Ta 0.098 B 0.015 The preparation process of solid solution alloys is as follows:

[0072] (1) The first step is to prepare (Hf) 90 Ta 10 ) 98.5 B 1.5Amorphous powder

[0073] First, using industrial-grade pure Hf (>99%), Ta (>99.5%), and B (>99%) as raw materials, a mixture with a weight percentage composition of (Hf) was prepared. 90 Ta 10 ) 98.5 B 1.5 The alloy was placed in a water-cooled copper crucible in a non-consumable arc furnace and evacuated to a vacuum of 3 × 10⁻⁶. -2 Pa, and 0.01 MPa of industrial pure Ar gas is introduced for non-consumable arc melting, with a melting working current of 200 A; the alloy is repeatedly melted by turning it upside down 3 times to obtain an alloy ingot with uniform composition.

[0074] (Hf) 90 Ta 10 ) 98.5 B 1.5 The alloy ingot was crushed and placed in a graphite crucible for atomization powder preparation: it was heated to 1750℃ (above the melting point of the alloy ingot) by medium-frequency induction heating and held for 2 minutes. The powder was then sprayed out and cooled using atomization technology (atomizing gas pressure of 2 MPa, guide rod nozzle orifice diameter of 1 mm) to obtain spherical powder material with a particle size between 10 and 30 μm, which was then sieved and set aside. X-ray diffraction (XRD) results are shown below. Figure 5 As shown: This indicates that the powder has an amorphous structure.

[0075] (2) The second step is to prepare W 99 Hf 0.887 Ta 0.098 B 0.015 solid solution dilute solid solution alloy

[0076] Using commercially available pure W powder (>99.9%) with a particle size of 8μm as the material matrix, and Hf with a particle size of 10-13μm... 90 Ta 10 ) 98.5 B 1.5 Amorphous powder (sieved using 1000-mesh and 1340-mesh sieves) was used as raw material, weighed, and formulated with a nominal composition of W. 99 [(Hf 90 Ta 10 ) 98.5 B 1.5 ]1 (i.e. W) 99 Hf 0.887 Ta 0.098 B 0.015 Alloy. After mixing the powder raw materials, they were loaded into a ball mill jar together with grinding balls (material-to-ball ratio of 1:10) and subjected to high-energy ball milling in an argon atmosphere. The ball mill speed was 200 rpm and the ball milling time was 5 hours.

[0077] The thoroughly mixed powder raw materials were loaded into a vacuum hot-pressing sintering furnace for sintering to produce the target alloy sintered body. The preload pressure during sintering was 30 MPa, and the vacuum degree was 1 × 10⁻⁶. -2 The sintering temperature was 1700℃, the sintering pressure was 70MPa, and the holding time was 180min. The furnace was then cooled to room temperature, and the sintered sample was removed. The density of the sintered body was measured to be 96.2%. X-ray diffraction (XRD) results are as follows: Figure 6 As shown: This indicates that the sintered body has a single-phase BCC structure. Optical microscopy revealed that the average grain size of the sintered body is approximately 5 μm, and the grain size at the fracture surface is as follows. Figure 7 As shown.

[0078] Next, the sintered billet sample was heated to 1600℃ and held for 30 min. Then, it was rapidly placed in a high-speed pneumatic forging hammer for forging at a forging pressure of 40 MPa, with the forging direction along the central axis of the cylindrical sintered billet sample. Finally, the mechanical and thermal conductivity properties of the forged sample were tested. The results show that W 99 Hf 0.887 Ta 0.098 B 0.015 The thermal conductivity of rare-density solid solution alloys from 30℃ to 600℃ exceeds that of pure W under the same conditions by 99%; their yield strength at 400℃ is close to 1000MPa, and their plasticity reaches 18%. Figure 8 As shown, it exhibits good overall high-temperature performance.

[0079] Example 3:

[0080] A tungsten-based solid solution alloy comprises a matrix and alloying elements dissolved in the matrix, wherein the matrix is ​​metallic tungsten; and the alloying elements include hafnium, tantalum, and boron. The chemical formula of the tungsten-based solid solution alloy is W. 97 Hf 0.887 Ta 2.068 B 0.045 .

[0081] W 97 Hf 0.887 Ta 2.068 B 0.045 The preparation process of solid solution alloys is as follows:

[0082] (1) The first step is to prepare (Hf) 30 Ta 70 ) 98.5 B 1.5 Amorphous powder

[0083] First, using industrial-grade pure Hf (>99%), Ta (>99.5%), and B (>99%) as raw materials, a mixture with a weight percentage composition of (Hf) was prepared. 30 Ta 70 ) 98.5B 1.5 The alloy was placed in a water-cooled copper crucible in a non-consumable arc furnace and evacuated to a vacuum of 1×10⁻⁶. -2 Pa, and 0.01 MPa of industrial pure Ar gas is introduced for non-consumable arc melting, with a melting working current of 250 A; the alloy is repeatedly melted by turning it upside down 3 times to obtain an alloy ingot with uniform composition.

[0084] (Hf) 30 Ta 70 ) 98.5 B 1.5 The alloy ingot was crushed and placed in a graphite crucible for atomization powder preparation: it was heated to 1900℃ (above the melting point of the alloy ingot) by medium-frequency induction heating and held for 5 minutes. The powder was then sprayed out and cooled using atomization technology (atomizing gas pressure of 5 MPa, guide rod nozzle orifice diameter of 1 mm) to obtain spherical powder material with a particle size between 5 and 20 μm, which was then sieved and set aside. X-ray diffraction (XRD) was performed as follows... Figure 9 As shown, the results indicate that the powder has an amorphous structure.

[0085] (2) The second step is to prepare W 97 Hf 0.887 Ta 2.068 B 0.045 solid solution dilute solid solution alloy

[0086] Using commercially available pure W powder (>99.9%) with a particle size of 5μm as the material matrix, and Hf with a particle size of 5-10μm... 30 Ta 70 ) 98.5 B 1.5 Amorphous powder (sieved using 1340-mesh and 5000-mesh sieves) was used as raw material, weighed, and prepared with a nominal composition of W. 97 [(Hf 30 Ta 70 ) 98.5 B 1.5 ]3 (i.e. W) 97 Hf 0.887 Ta 2.068 B 0.045 Alloy. After mixing the powder raw materials, they were loaded into a ball mill jar together with grinding balls (material-to-ball ratio of 1:8) and subjected to high-energy ball milling in an argon atmosphere. The ball mill speed was 180 rpm and the ball milling time was 3 hours.

[0087] The thoroughly mixed powder raw materials were loaded into a vacuum hot-pressing sintering furnace for sintering to produce the target alloy sintered body. The preload pressure during sintering was 30 MPa, and the vacuum degree was 1 × 10⁻⁶. -2The sintering temperature was 1850℃, the sintering pressure was 70MPa, and the holding time was 60min. The furnace was then cooled to room temperature, and the sintered sample was removed. The density of the sintered body was measured to be 95.3%. X-ray diffraction (XRD) results are as follows: Figure 10 As shown: This indicates that the sintered body has a single-phase BCC structure. Optical microscopy revealed that the average grain size of the sintered body is approximately 3 μm, and the grain size at the fracture surface is as follows. Figure 11 As shown.

[0088] Next, the sintered billet sample was heated to 1600℃ and held for 30 min. Then, it was rapidly placed in a high-speed pneumatic forging hammer for forging at a forging pressure of 40 MPa, with the forging direction along the central axis of the cylindrical sintered billet sample. Finally, the mechanical and thermal conductivity properties of the forged sample were tested. The results show that W 97 Hf 0.887 Ta 2.068 B 0.045 The thermal conductivity of rare-density solid solution alloys from 30℃ to 600℃ exceeds that of pure W under the same conditions by 96%; their yield strength at 400℃ is close to 1000MPa. Figure 12 As shown, the plastic deformation reaches 15%, indicating good overall high-temperature performance.

[0089] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A tungsten-based solid solution alloy, characterized in that, It includes a matrix and alloying elements dissolved in the matrix, wherein the matrix is ​​metallic tungsten; and the alloying elements include hafnium, tantalum, and boron. The chemical composition of the tungsten-based solid solution alloy, by weight percentage, is W 100-a (Hf,Ta,B) a Where 1 ≤ a ≤ 3; The chemical formulas of hafnium, tantalum, and boron, by weight percentage, are (Hf 100-b Ta b ) 98.5 B 1.5 Where 10≤b≤70.

2. The method for preparing the tungsten-based solid solution alloy as described in claim 1, characterized in that, Includes the following steps: S1. Amorphous powder containing alloying elements is prepared by combining electric arc melting with melt atomization technology; S2. The amorphous powder prepared in step S1 is ball-milled and mixed with tungsten powder to form a mixture. S3. Prepare an alloy sintered body by hot pressing and sintering the mixture obtained in step S2; S4. The alloy sintered body obtained in step S3 is subjected to high-energy-rate forging treatment.

3. The preparation method according to claim 2, characterized in that, Step S1 includes the following steps: S11. After mixing the alloying elements, place them in a non-consumable arc melting furnace and introduce argon gas to prepare alloy ingots through non-consumable arc melting. S12. After crushing the alloy ingot prepared in step S11, atomize it to obtain amorphous powder.

4. The preparation method according to claim 3, characterized in that, During non-consumable arc melting, the working current is 200~250A; the atomization powder production process is as follows: After the alloy ingot is crushed, it is placed in a graphite crucible and heated to a temperature higher than the melting point of the alloying elements. The temperature is held for 2-5 minutes. Then, the molten alloying elements are sprayed out and cooled using atomization technology to obtain spherical powder material.

5. The preparation method according to claim 2, characterized in that, In step S2, the ball-to-material ratio of the ball mill mixture is 1:5 to 1:10, the ball milling time is 2 to 5 hours, and the ball mill speed is 150 to 200 rpm.

6. The preparation method according to claim 2, characterized in that, In step S3, the preload pressure for hot pressing sintering is 30 MPa, and the vacuum degree is 1 × 10⁻⁶. -2 Pa, sintering temperature is 1750-1850℃, sintering pressure is 70MPa, and holding time is 60-180min.

7. The preparation method according to claim 2, characterized in that, In step S4, the specific process of high-energy-rate forging is as follows: First, heat the sintered billet to 1600 ℃ and hold for 30 min. Then, quickly place it in a high-speed pneumatic forging hammer for forging. The forging pressure is 40 MPa, and the forging direction is along the central axis of the cylindrical sintered billet.

8. The application of the tungsten-based solid solution alloy as described in claim 1 in a magnetically confined fusion reactor, characterized in that, This includes components used in the fabrication of plasma.

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