Multi-component particle synergistically reinforced ultra-fine grain tungsten alloy and preparation method thereof

Abstract

The application discloses a preparation method of a multi-component particle synergistically reinforced ultra-fine grain tungsten alloy, which adopts tungsten powder, transition group metal powder and rare earth element oxide powder as raw materials, carries out periodic variable-speed ball milling and two-step low-temperature sintering; each cycle is the treatment of low-speed ball milling first and high-speed ball milling later, and the two-step low-temperature sintering includes pre-sintering and sintering treatment; and the application further discloses a multi-component particle synergistically reinforced ultra-fine grain tungsten alloy. The preparation method of the application introduces uniformly dispersed transition group metal element oxides and complex oxides in a tungsten matrix by adopting tungsten powder, transition group metal powder and rare earth element oxide powder as raw materials, combining variable-speed ball milling and low-temperature sintering, adjusts and controls the ultra-fine grain structure and improves the interface bonding characteristics of tungsten and oxides, effectively improves the room temperature brittleness of the tungsten alloy, reduces the ductile-brittle transition temperature, and is suitable for the preparation of plasma-facing materials.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy preparation technology of refractory metals and their alloys, and in particular relates to a multi-component particle synergistic reinforcement ultrafine crystalline tungsten alloy and its preparation method. Background Technology

[0002] Controlled thermonuclear fusion energy is considered the best potential clean energy source for the future, as its products pose no radioactive hazard to the natural environment, and its main component, deuterium, is abundant in the ocean. However, to achieve the rational utilization of fusion energy, many technical challenges need to be overcome, among which selecting suitable plasma-oriented materials (PFMs) is crucial.

[0003] The primary function of plasma flow meters (PFMs) is to regulate impurities infiltrated into the plasma, effectively conduct radiative energy, and protect other devices from plasma collision damage during unconventional shutdown conditions. Tungsten (W)-based materials have broad application prospects in PFMs due to their advantages such as high melting point, good thermal conductivity, low tritium retention, high self-sputtering threshold, and low sputtering yield. However, the practical application of tungsten in PFMs is limited by inherent material drawbacks, including high processing difficulty, high ductile-brittle transition temperature, and recrystallization brittleness. Furthermore, the fast neutrons generated by fusion reactions have extremely strong material penetrating power, causing irradiation damage to conventional materials, leading to material embrittlement and reduced service life. The design of tungsten-based materials for PFMs requires consideration of material composition, microstructure, and structure. Advanced material design techniques such as alloying and second-phase particle dispersion strengthening, combined with special structural designs such as ultrafine grains, are needed to improve the service performance of tungsten-based materials.

[0004] While nano-oxide particle dispersion strengthening of tungsten alloys can improve the mechanical properties of tungsten to some extent, its development also faces certain bottlenecks. On the one hand, the van der Waals forces between nano-oxide particles, their large specific surface area, and the high density and hardness of tungsten result in low ball milling efficiency, easy cold welding and agglomeration of the powder, making it difficult to achieve uniform dispersion of nano-sized oxides (such as Y₂O₃). This leads to easy agglomeration of oxide particles, reducing the strengthening effect. On the other hand, due to the high melting point of tungsten, the sintering temperature of conventional powder metallurgy is relatively high, further exacerbating the coarsening and growth of oxide particles. The size of nano-ceramic particles in the prepared tungsten alloys often reaches tens of micrometers, severely reducing the strengthening efficiency and easily leading to the deterioration of the mechanical properties of the tungsten alloy. Furthermore, the large differences in physical properties between tungsten and oxide interfaces (such as the coefficient of thermal expansion) often result in defects such as pores and weak bonding at the interface, directly affecting the strengthening efficiency of oxide particles. During service, these interface defects easily cause crack initiation, promote crack propagation, exacerbate the room temperature brittleness of tungsten alloys, and cause early failure of tungsten alloy structural components. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing multi-component particle synergistic reinforcement of ultrafine-grained tungsten alloys. This method uses tungsten powder, transition metal powder, and rare earth element oxide powder as raw materials, combined with periodic variable-speed ball milling and low-temperature sintering processes. This allows for the introduction of uniformly dispersed transition metal element oxides and complex oxides into the tungsten matrix, regulating the ultrafine-grained structure and improving the interfacial bonding characteristics between tungsten and oxides. This effectively improves the room-temperature brittleness of tungsten alloys, lowers the ductile-brittle transition temperature, and solves the problem that nano-oxide particle dispersion-reinforced tungsten alloys cannot simultaneously achieve high strength and high plasticity.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a method for preparing a multi-component particle synergistic reinforcement ultrafine crystalline tungsten alloy, characterized in that the preparation method uses tungsten powder, transition metal powder and rare earth element oxide powder as raw materials, and performs periodic variable speed ball milling and two-step low-temperature sintering to obtain an ultrafine crystalline tungsten alloy; each cycle of the periodic variable speed ball milling is a process of first low-speed ball milling and then high-speed ball milling, and the two-step low-temperature sintering includes pre-sintering and sintering treatment.

[0007] This invention uses the periodic change of rotation speed between low-speed ball milling and high-speed ball milling to subject the powder to alternating forces under different impact and shear energies. This helps prevent the powder from agglomerating or accumulating in "dead zones" during high-energy ball milling, resulting in near-spherical powder with a narrow particle size distribution. This improves the powder's flowability and forming density, and helps promote the in-situ synthesis of complex oxides and subsequent low-temperature sintering. Furthermore, the high-speed ball milling stage enhances the interfacial friction and diffusion between the oxide and the tungsten matrix, while the low-speed stage promotes the release and recombination of interfacial stress, ultimately forming a stable interfacial structure. The alternation of these two stages improves the thermal stability and resistance to coarsening and growth of oxide particles, and contributes to good tungsten / oxide interfacial bonding. This avoids the limitations of traditional single-speed ball milling in the preparation of tungsten alloys. For example, constant high speed leads to excessive cold welding of powder, excessive temperature rise, and serious introduction of impurities due to excessive energy input, while constant low speed cannot effectively break up high-hardness and high-density tungsten powder due to insufficient energy input, and cannot achieve nanoscale dispersion of oxides.

[0008] The above-mentioned method for preparing a multi-component particle synergistic reinforcement ultrafine crystalline tungsten alloy is characterized in that the tungsten powder has a particle size of less than 5 μm, the transition metal powder has a particle size of less than 10 μm, and the rare earth element oxide powder has a particle size of 20 nm to 200 nm.

[0009] The preparation method of the above-mentioned multi-component particle synergistic reinforcement ultrafine crystalline tungsten alloy is characterized in that the transition metal powder accounts for 0.5% to 5% of the total mass of the raw materials, and the rare earth element oxide powder accounts for 0.3% to 10% of the total mass of the raw materials.

[0010] The above-mentioned method for preparing a multi-component particle synergistic reinforcement ultrafine crystalline tungsten alloy is characterized in that the transition metal powder is one or more of Ti, Zr, and Hf, and the rare earth element oxide powder is Y2O3 and / or La2O3.

[0011] The above-mentioned method for preparing a multi-component particle synergistic reinforcement ultrafine crystalline tungsten alloy is characterized in that the rotation speed of the low-speed ball mill is 100 rpm to 250 rpm, the low-speed ball milling time is 1 h to 5 h, the rotation speed of the high-speed ball mill is 350 rpm to 500 rpm, the high-speed ball milling time is 1 h to 4 h, and the periodic variable speed ball milling time is 10 h to 20 h.

[0012] This invention reduces the introduction of impurity elements while ensuring the effectiveness of variable speed ball milling by controlling the entire variable speed ball milling time and configuring the rotation speed and milling time appropriately.

[0013] The above-mentioned method for preparing a multi-component particle synergistic reinforcement ultrafine crystalline tungsten alloy is characterized in that the milling medium of the variable speed ball mill is tungsten carbide balls, the diameter of the tungsten carbide balls is 5mm~10mm, and the ball-to-material ratio of the variable speed ball mill is 5~15:1.

[0014] This invention, by controlling the diameter of the grinding balls to be relatively small, helps to break up the agglomerates of rare earth element oxide powder particles during the ball milling process, providing more interaction surfaces with tungsten powder, and promoting the embedding of transition metal powder and rare earth element oxide powder.

[0015] The above-mentioned method for preparing a multi-component particle-synergistically reinforced ultrafine crystalline tungsten alloy is characterized in that the low-temperature sintering adopts a spark plasma sintering process.

[0016] The above-mentioned method for preparing a multi-component particle-synergistically reinforced ultrafine crystalline tungsten alloy is characterized in that the pre-sintering process is as follows: under vacuum and pressure of 50MPa~100MPa, the temperature is raised to 900℃~1100℃ at a rate of 50℃ / min~150℃ / min and held for 3min~10min; the sintering process is as follows: under vacuum and pressure of 50MPa~100MPa, the temperature is raised to 1400℃~1600℃ at a rate of 50℃ / min~150℃ / min and held for 5min~20min, and then cooled at a rate of 50℃ / min~150℃ / min.

[0017] This invention employs a spark plasma sintering process with two-step low-temperature sintering. Pre-sintering removes gaseous impurities, followed by heating to the sintering temperature. This sintering temperature ensures high sintering density and effectively inhibits oxide coarsening and growth, promoting a uniform and dispersed distribution of oxide particles. It also suppresses grain growth to form an ultrafine-grained structure and promotes interfacial metallurgical bonding between the oxide and the tungsten matrix, enhancing the interfacial stability of the composite system. Controlling the sintering pressure promotes dense sintering and good tungsten / oxide interfacial bonding. Controlling the heating and cooling rates reduces internal thermal stress in the material. Furthermore, low-temperature sintering offers energy-saving and high-efficiency advantages, thereby reducing costs, simplifying the process, and facilitating mass production.

[0018] The present invention also discloses a multi-component particle synergistic reinforcement ultrafine tungsten alloy, characterized in that it is obtained by the above preparation method, the ultrafine tungsten alloy is composed of a tungsten matrix, transition metal element oxides and complex oxides, the complex oxides are formed in situ by transition metal elements and oxide particles, and the average grain size of the ultrafine tungsten alloy is less than 1 μm.

[0019] This invention controls the grain size of the ultrafine-grained tungsten alloy, resulting in a high-density grain boundary distribution in the ultrafine-grained microstructure. This provides grain refinement and increases the distribution density of impurity elements such as carbon and oxygen, thereby improving the strength and plasticity of the ultrafine-grained tungsten alloy.

[0020] The above-mentioned multi-component particle synergistic reinforcement ultrafine crystalline tungsten alloy is characterized in that the ultrafine crystalline tungsten alloy is composed of the following components in volume percentage: 1%~15% transition metal element oxides, 1%~10% complex oxides, and the balance being tungsten and unavoidable impurities.

[0021] Compared with the prior art, the present invention has the following advantages: 1. This invention targets the high density and high hardness characteristics of tungsten alloys. By periodically changing the rotation speed, the powder is subjected to alternating forces under different impact and shear energies. This results in finer and more uniformly distributed oxide dispersion-strengthened particles. The high-speed stage enhances the interfacial friction and diffusion between the oxide and the tungsten matrix, while the low-speed stage promotes the release and recombination of interfacial stress, forming a stable tungsten / oxide interface structure. This improves the thermal stability and resistance to coarsening and growth of oxide particles. At the same time, it helps to reduce the sintering temperature of tungsten alloys, enabling low-temperature sintering.

[0022] 2. This invention effectively suppresses the coarsening and aggregation of oxide particles by employing a composite process of variable speed ball milling and two-step low-temperature sintering, promoting their uniform dispersion in the tungsten matrix. During the sintering process, it can significantly inhibit grain growth, forming an ultrafine grain structure, while promoting the interfacial metallurgical bonding between oxide particles and the tungsten matrix, thereby improving the interfacial stability of the composite system, effectively improving the room temperature brittleness of tungsten alloys, and reducing the ductile-brittle transition temperature.

[0023] 3. This invention introduces in-situ generated fine and complex oxide particles and transition metal oxides dispersed in the tungsten matrix, and combines this with controlling the particle size and preparation process of transition metal powder and rare earth element oxide powder to form a multi-scale, multi-component synergistic strengthening effect. This promotes the synergistic improvement of the strength and plasticity of the ultrafine-grained tungsten alloy, improves the room temperature brittleness of tungsten materials, and gives the ultrafine-grained tungsten alloy excellent comprehensive mechanical properties. This ultrafine-grained tungsten alloy shows broad application prospects in the field of plasma materials for controlled nuclear fusion.

[0024] 4. This invention employs low-temperature sintering with spark plasma, which has advantages such as low energy consumption and high efficiency, helping to reduce preparation costs, simplify the process, and achieve mass production of ultrafine-grained tungsten alloys.

[0025] 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

[0026] Figure 1 This is a microscopic morphology diagram of the tungsten alloy ball milled powder in Example 1 of the present invention.

[0027] Figure 2 This is a microstructure diagram of the ultrafine-grained tungsten alloy in Example 1 of the present invention.

[0028] Figure 3 The image shows the compression test results of the ultrafine-grained tungsten alloy in Example 1 of this invention.

[0029] Figure 4 This is a microscopic morphology diagram of the tungsten ball-milled powder in Comparative Example 1 of the present invention.

[0030] Figure 5 This is a microstructure diagram of tungsten in Comparative Example 1 of the present invention.

[0031] Figure 6 The image shows the compression test results of tungsten in Comparative Example 1 of this invention.

[0032] Figure 7 This is a microstructure diagram of the ultrafine-grained tungsten alloy in Example 2 of the present invention.

[0033] Figure 8 This is a microscopic image of the interface between the tungsten matrix and oxide particles in the ultrafine crystalline tungsten alloy of Example 2 of the present invention.

[0034] Figure 9 This is a microstructure diagram of the tungsten alloy in Comparative Example 2 of the present invention. Detailed Implementation

[0035] Example 1 The preparation method of this embodiment is as follows: In a glove box under an argon atmosphere, tungsten powder with a particle size of less than 5 μm, titanium powder with a particle size of less than 10 μm, and yttrium oxide powder with an average particle size of 50 nm are used as raw materials for batching. The raw materials are composed of the following components in the indicated mass percentages: tungsten powder 97.5%, titanium powder 2%, and yttrium oxide powder 0.5%. The ball mill jar containing raw materials and grinding balls is installed in the ball mill. The tungsten carbide grinding balls are 5mm in size and the ball-to-material ratio is 10:1. The ball mill is performed at a low speed of 200 rpm for 3 hours, followed by a high speed of 400 rpm for 3 hours. The process of first low speed and then high speed ball milling is repeated once to obtain tungsten alloy ball mill powder. The total ball milling time is 12 hours. Then, the tungsten alloy ball-milled powder is loaded into a graphite sintering mold and subjected to spark plasma sintering at a vacuum degree better than 10. -2 Under the conditions of Pa and pressure of 80 MPa, the temperature is increased to 1000℃ at a rate of 100℃ / min and held for 5 min, then increased to 1600℃ at a rate of 100℃ / min and held for 10 min, and then cooled at a rate of 50℃ / min. After grinding and polishing, an ultrafine crystalline tungsten alloy is obtained.

[0036] The tungsten alloy powder obtained in this embodiment was characterized by scanning electron microscopy (SEM), such as... Figure 1 As shown, the tungsten alloy powder is generally equiaxed, and the particle size distribution is relatively uniform. The ultrafine-grained tungsten alloy obtained in this embodiment was characterized by SEM, as shown below. Figure 2 As shown, the ultrafine-grained tungsten alloy exhibits a relatively uniform microstructure with a grain size of 0.7 µm and a micro Vickers hardness of 809.6 HV. The second-phase particles, including TiO2 and Y2Ti2O7, are uniformly distributed within the tungsten matrix. Room temperature compression testing of this ultrafine-grained tungsten alloy yielded the following results: Figure 3 As shown, the compressive strength is 2494.3 MPa and the fracture strain is 15.5%, exhibiting excellent comprehensive mechanical properties.

[0037] Comparative Example 1 The difference between this comparative example and Example 1 is that the raw material is only tungsten powder.

[0038] The tungsten ball-milled powder after variable-speed ball milling in this comparative example was characterized by SEM, such as... Figure 4 As shown, the tungsten ball-milled powder exhibits severe cold welding and large dimensions; the sintered tungsten of this comparative example was characterized by SEM, as shown... Figure 5As shown, this tungsten exhibits obvious defects such as pores at grain boundaries. Compared to the ultrafine-grained tungsten alloy of Example 1, its grains are coarser, with an average grain size of 8µm, and its microVickers hardness is 410HV, lower than that of the ultrafine-grained tungsten alloy of Example 1. Room temperature compression tests were performed on this tungsten, and the results are as follows... Figure 6 As shown, the compressive strength is 1068 MPa and the fracture strain is 3.9%, both of which are much lower than those of the ultrafine-grained tungsten alloy in Example 1. This indicates that the ultrafine-grained structure of TiO2 and Y2Ti2O7 uniformly distributed in the tungsten matrix prepared in Example 1 can enhance the comprehensive mechanical properties.

[0039] Example 2 The difference between this embodiment and Embodiment 1 is that the raw materials consist of the following components by mass percentage: 97% tungsten powder, 2% titanium powder, and 1% yttrium oxide powder; the low-temperature sintering process is as follows: spark plasma sintering is performed at a vacuum level better than 10... -2 Under the conditions of Pa and pressure of 100 MPa, the temperature is increased to 1000℃ at a rate of 100℃ / min and held for 10 min, then increased to 1600℃ at a rate of 100℃ / min and held for 5 min, and then cooled at a rate of 50℃ / min.

[0040] The ultrafine-grained tungsten alloy obtained in this embodiment was characterized by SEM, such as... Figure 7 As shown, the ultrafine-grained tungsten alloy exhibits a relatively uniform microstructure with a grain size of 0.51 µm and a micro Vickers hardness of 940.5 HV. The second-phase particles, including TiO2 and Y2Ti2O7, are uniformly distributed within the tungsten matrix. TEM characterization of this ultrafine-grained tungsten alloy is shown in the following figures. Figure 8 As shown, the tungsten matrix and oxide particles have good interfacial bonding with no obvious interfacial defects. The ultrafine-grained tungsten alloy was subjected to room temperature compression test and showed a compressive strength of 2893.8 MPa and a fracture strain of 19.6%, which indicates excellent comprehensive mechanical properties.

[0041] Comparative Example 2 The difference between this comparative example and Example 2 is that the ball milling was performed at a constant speed of 300 rpm for 12 hours.

[0042] Microstructure analysis was performed on the tungsten alloy obtained by sintering in this comparative example, such as... Figure 9 As shown, compared with the ultrafine-grained tungsten alloy of Example 2, the average grain size of this tungsten alloy is 1.9µm, which is larger than the grain size of Example 2, and it does not achieve an ultrafine-grained structure (<1µm). In addition, there are large oxide particles in this tungsten alloy, which are unevenly distributed, and there are obvious pore defects at the interface between the oxide particles and the matrix. The micro Vickers hardness of this comparative tungsten alloy was measured to be 850.1HV, the room temperature compressive strength was 2523.3MPa, and the fracture strain was 10.1%, all of which were lower than those of Example 2. In summary, under the same composition design, the variable speed ball milling + low temperature sintering process proposed in this invention can greatly improve the uniform dispersion distribution of oxide particles, improve interfacial bonding, promote low temperature sintering densification, and improve room temperature brittleness.

[0043] Example 3 The preparation method of this embodiment is as follows: In a glove box under an argon atmosphere, tungsten powder with a particle size of less than 5 μm, hafnium powder with a particle size of less than 10 μm, and yttrium oxide powder with an average particle size of 20 nm are used as raw materials for batching. The raw materials are composed of the following components in the indicated mass percentages: tungsten powder 99.2%, hafnium powder 0.5%, and yttrium oxide powder 0.3%. The ball mill jar containing raw materials and grinding balls is installed in the ball mill. The tungsten carbide grinding balls are 10mm in size and the ball-to-material ratio is 15:1. The ball mill is performed at a low speed of 250rpm for 1 hour, followed by a high speed of 500rpm for 4 hours. The process of first low speed and then high speed ball milling is repeated once to obtain tungsten alloy ball mill powder. The total ball milling time is 10 hours. Then, the tungsten alloy ball mill powder is loaded into a graphite sintering mold and sintered under a vacuum degree better than 10. -2 Under the conditions of Pa and pressure of 100 MPa, the temperature is increased to 1100℃ at a rate of 150℃ / min and held for 3 min, then increased to 1400℃ at a rate of 150℃ / min and held for 20 min, and then cooled at a rate of 100℃ / min to obtain an ultrafine crystalline tungsten alloy.

[0044] Upon inspection, the second phase particles in the ultrafine crystalline tungsten alloy obtained in this embodiment include HfO2 and Y2Hf2O7 and are uniformly distributed in the tungsten matrix. The micro Vickers hardness is 560.2 HV, the compressive strength is 1834.5 MPa, and the fracture strain is 25.3%.

[0045] Example 4 The preparation method of this embodiment is as follows: In a glove box under an argon atmosphere, tungsten powder with a particle size of less than 5 μm, zirconium powder with a particle size of less than 10 μm, and lanthanum oxide powder with an average particle size of 200 nm are used as raw materials for batching. The raw materials are composed of the following components in the following mass percentages: 85% tungsten powder, 5% zirconium powder, and 10% lanthanum oxide powder. The ball mill jar containing raw materials and grinding balls is installed in the ball mill. The tungsten carbide grinding balls are 8mm in size and the ball-to-material ratio is 10:1. The ball mill is performed at a low speed of 100rpm for 5 hours, followed by a high speed of 350rpm for 4 hours. The process of first low speed and then high speed ball milling is repeated once to obtain tungsten alloy ball mill powder. The total ball milling time is 18 hours. Then, the tungsten alloy ball mill powder is loaded into a graphite sintering mold and sintered under a vacuum degree better than 10. -2Under the conditions of Pa and pressure of 50 MPa, the temperature is increased to 1000℃ at a rate of 50℃ / min and held for 5 min, then increased to 1500℃ at a rate of 50℃ / min and held for 10 min, and then cooled at a rate of 50℃ / min to obtain an ultrafine crystalline tungsten alloy.

[0046] Upon inspection, the second phase particles in the ultrafine crystalline tungsten alloy obtained in this embodiment include ZrO2 and La2Zr2O7 and are uniformly distributed in the tungsten matrix. The micro Vickers hardness is 1204.3 HV, the compressive strength is 3256.1 MPa, and the fracture strain is 15.4%.

[0047] Example 5 The preparation method of this embodiment is as follows: In a glove box under an argon atmosphere, tungsten powder with a particle size of less than 5 μm, hafnium powder with a particle size of less than 10 μm, and lanthanum oxide powder with an average particle size of 100 nm are used as raw materials for batching. The raw materials are composed of the following components in the following mass percentages: tungsten powder 92%, hafnium powder 3%, and lanthanum oxide powder 5%. The ball mill jar containing raw materials and grinding balls was installed in the ball mill. The tungsten carbide grinding balls were 5 mm in size and the ball-to-material ratio was 5:1. The ball milling was carried out at a low speed of 200 rpm for 4 hours, followed by a high speed of 500 rpm for 1 hour. The process of first low speed and then high speed ball milling was repeated three times to obtain tungsten alloy ball mill powder. The total ball milling time was 20 hours. Then, the tungsten alloy ball mill powder is loaded into a graphite sintering mold and sintered under a vacuum degree better than 10. -2 Under the conditions of Pa and pressure of 80 MPa, the temperature is increased to 900℃ at a rate of 100℃ / min and held for 10 min, then increased to 1600℃ at a rate of 100℃ / min and held for 10 min, and then cooled at a rate of 80℃ / min to obtain an ultrafine crystalline tungsten alloy.

[0048] Upon inspection, the second phase particles in the ultrafine crystalline tungsten alloy obtained in this embodiment include HfO2 and La2Hf2O7 and are uniformly distributed in the tungsten matrix. The micro Vickers hardness is 1035.8 HV, the compressive strength is 2932.5 MPa, and the fracture strain is 17.9%.

[0049] Example 6 The difference between this embodiment and Embodiment 5 is that the cooling rate is 150℃ / min.

[0050] Upon inspection, the second phase particles in the ultrafine crystalline tungsten alloy obtained in this embodiment include HfO2 and La2Hf2O7 and are uniformly distributed in the tungsten matrix. The micro Vickers hardness is 1049.6 HV, the compressive strength is 2953.2 MPa, and the fracture strain is 16.5%.

[0051] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a multi-component particle-reinforced ultrafine-grained tungsten alloy, characterized in that, This preparation method uses tungsten powder, transition metal powder, and rare earth element oxide powder as raw materials, and performs periodic variable speed ball milling and two-step low-temperature sintering to obtain an ultrafine-grained tungsten alloy. Each cycle of the periodic variable speed ball milling consists of low-speed ball milling followed by high-speed ball milling. The two-step low-temperature sintering includes pre-sintering and sintering. The pre-sintering temperature is 900℃~1100℃, and the sintering temperature is 1400℃~1600℃. The ultrafine-grained tungsten alloy is composed of a tungsten matrix, transition metal element oxides, and complex oxides. The tungsten powder has a particle size of less than 5 μm, the transition metal powder has a particle size of less than 10 μm, and the rare earth element oxide powder has a particle size of 20 nm to 200 nm; the transition metal powder accounts for 0.5% to 5% of the total mass of the raw materials, and the rare earth element oxide powder accounts for 0.3% to 10% of the total mass of the raw materials; the transition metal powder is one or more of Ti, Zr, and Hf, and the rare earth element oxide powder is Y2O3 and / or La2O3; The low-speed ball mill operates at a rotation speed of 100 rpm to 250 rpm for 1 hour to 5 hours; the high-speed ball mill operates at a rotation speed of 350 rpm to 500 rpm for 1 hour to 4 hours; and the periodic variable-speed ball mill operates for 10 hours to 20 hours. The milling media in the variable-speed ball mill is tungsten carbide balls with a diameter of 5 mm to 10 mm, and the ball-to-material ratio is 5 to 15:

1.

2. The method for preparing a multi-component particle-reinforced ultrafine-grained tungsten alloy according to claim 1, characterized in that, The low-temperature sintering is carried out using a spark plasma sintering process.

3. The method for preparing a multi-component particle-reinforced ultrafine-grained tungsten alloy according to claim 1, characterized in that, The pre-sintering process is as follows: under vacuum and pressure of 50MPa~100MPa, the temperature is increased to 900℃~1100℃ at a rate of 50℃ / min~150℃ / min and held for 3min~10min. The sintering process is as follows: under vacuum and pressure of 50MPa~100MPa, the temperature is increased to 1400℃~1600℃ at a rate of 50℃ / min~150℃ / min and held for 5min~20min, and then the temperature is decreased at a rate of 50℃ / min~150℃ / min.

4. A multi-component particle-reinforced ultrafine-grained tungsten alloy, characterized in that, The complex oxide is obtained by the preparation method according to any one of claims 1 to 3, wherein the complex oxide is formed in situ from transition metal elements and oxide particles, and the average grain size of the ultrafine tungsten alloy is less than 1 μm; the ultrafine tungsten alloy is composed of the following components in volume percentage: 1% to 15% transition metal element oxides, 1% to 10% complex oxides, and the balance being tungsten and unavoidable impurities.

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