A La2O3 particle-reinforced molybdenum-tungsten alloy and its preparation method

Abstract

This invention relates to a La2O3 particle-reinforced molybdenum-tungsten alloy and its preparation method. First, molybdenum powder and lanthanum oxide nanoparticles are mixed at a mass ratio of 9:1 and ball-milled to obtain a Mo-10%La2O3 masterbatch. Then, the masterbatch is mixed with tungsten powder and molybdenum powder in a final alloy composition of Mo-30%W-xLa2O3 (x=0.1-1.0%) and ball-milled a second time. The mixed powder is pressed into a green blank, sintered at high temperature to obtain a sintered blank, and then subjected to roughing and multi-pass rolling to obtain a rolled sheet of lanthanum oxide particle-reinforced molybdenum-tungsten alloy. The addition of lanthanum oxide particles refines and homogenizes the grains of the tungsten-molybdenum alloy, solving the problem of abnormal grain growth in the sintered state of traditional tungsten-molybdenum alloys. The "stepwise doping ball-milling process" ensures that the lanthanum oxide particles are uniformly distributed on the Mo-30%W matrix, solving the problems of agglomeration and uneven distribution of nano-oxide particles, and improving the hardness, strength, and plasticity of the molybdenum-tungsten alloy.

Description

Technical Field

[0001] This invention belongs to the field of refractory metal material preparation technology, specifically a La2O3 particle-reinforced molybdenum-tungsten alloy and its preparation method. Background Technology

[0002] Mo-W alloys, as typical refractory metals, possess high melting points, excellent high-temperature strength, and good thermal and electrical conductivity. Among many refractory metals, molybdenum (Mo) and tungsten (W) hold an irreplaceable position due to their extremely high melting points. Molybdenum-tungsten alloys (Mo-W) cleverly combine the good toughness and machinability of molybdenum with the extremely high melting point, high modulus, and excellent corrosion resistance of tungsten through a solid solution strengthening mechanism, demonstrating enormous application potential and being widely used in extreme environments such as aerospace and nuclear industry. However, pure molybdenum-tungsten alloys suffer from problems such as high room-temperature brittleness and insufficient high-temperature creep resistance, requiring doping modification to improve their overall performance.

[0003] In recent years, ODS (oxide dispersion strengthening) technology has been regarded as one of the most effective ways to solve the brittleness of refractory metals and improve their high-temperature performance. This technology introduces nanoscale, thermally stable oxide particles into the metal matrix and utilizes their strong "pinning" effect to hinder grain boundary migration and dislocation movement, thereby significantly refining grains, increasing recrystallization temperature, and enhancing high-temperature strength and creep resistance.

[0004] Among various oxide-reinforcing phases, nano-lanthanum oxide (La2O3) is highly favored due to its unique advantages. La2O3 possesses a high melting point (2315°C) and excellent thermal stability, resisting decomposition or coarsening at high temperatures. More importantly, as a rare-earth oxide, La2O3 exhibits high chemical reactivity, interacting with the Mo matrix during preparation to effectively purify impurity elements (such as O and N) at grain boundaries, enhancing grain boundary bonding and thus lowering the ductile-brittle transition temperature. Studies have shown that adding nano-La2O3 to pure molybdenum can significantly refine the grains, increase the recrystallization temperature by over 200°C, and substantially improve room-temperature toughness and high-temperature strength.

[0005] Currently, most research focuses on ODS pure molybdenum or low-W molybdenum alloy systems. For molybdenum-tungsten alloys with specific applications, the evolution of their microstructure and the mechanisms of action due to the introduction of nano-La2O3 are still lacking in systematic and in-depth research. Achieving highly uniform dispersion of La2O3 in a Mo-W dual-phase matrix and improving the hardness, strength, and plasticity of molybdenum-tungsten alloys is a current technical challenge facing the industry. Summary of the Invention

[0006] To address the above problems, this invention provides a La2O3 particle-reinforced molybdenum-tungsten alloy and its preparation method. The method employs a "stepwise doping ball milling process," first preparing a Mo-10%La2O3 masterbatch, then mixing the Mo-10%La2O3 masterbatch with tungsten powder and molybdenum powder in a secondary ball milling process. The appropriate addition of second-phase La2O3 nanoparticles refines the grain size of the molybdenum-tungsten alloy, effectively solving the problem of abnormal grain growth in the sintered state of traditional molybdenum-tungsten alloys. Through stepwise powder mixing, La2O3 particles are uniformly distributed in the alloy matrix, solving the problems of agglomeration and uneven distribution of nano-oxide particles, and improving the hardness, strength, and plasticity of the molybdenum-tungsten alloy.

[0007] This invention is specifically achieved through the following technical solution: a method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy according to this invention includes the following steps: (1) Molybdenum powder and La2O3 nanoparticles were mixed at a mass ratio of 9:1 and ball-milled for the first time under argon protection with a ball-to-material ratio of 10:1 to obtain Mo-10%La2O3 masterbatch, in which the mass percentage of La2O3 was 10%. At this time, the ball-to-material ratio was very high, the ball-milling effect was great, and it could effectively disperse the agglomerated particles in the La2O3 nanoparticles; (2) According to the final alloy composition of Mo-30%W-xLa2O3, take a certain amount of Mo-10%La2O3 masterbatch prepared in step (1), mix it with a certain amount of tungsten powder and molybdenum powder, put the mixed powder into a ball mill, control the ball-to-material ratio to be 1:1, and carry out a second ball milling under argon protection to obtain mixed powder; at this time the ball-to-material ratio is very low, the ball milling effect is small, and it mainly plays a stirring role. With fewer balls and more material, the production efficiency is high. In the Mo-30%W-xLa2O3 described in this step, the mass percentage of W is 30%, the mass percentage of La2O3 is x, the value of x is 0.1-1.0%, and the balance is Mo; (3) The mixed powder obtained in step (2) is loaded into a rubber mold and pressed into shape by cold isostatic pressing to obtain a blank; (4) The green blank obtained in step (3) is sintered in a hydrogen atmosphere at a sintering temperature of 2100℃~2200℃ to obtain a sintered La2O3 particle-reinforced molybdenum-tungsten alloy, namely a sintered Mo-30%W-xLa2O3 alloy, where x is 0.1-1.0%; (5) The sintered La2O3 particle-reinforced molybdenum-tungsten alloy obtained in step (4) is rolled at 1400℃ and then rolled in multiple passes to obtain La2O3 particle-reinforced molybdenum-tungsten alloy rolled sheet.

[0008] In the aforementioned method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy, the ball milling speed in step (1) is set to 300-400 rpm and the ball milling time is 20-24 h.

[0009] In the aforementioned method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy, the ball milling speed in step (2) is set to 250-350 rpm and the ball milling time is 20-24 h.

[0010] In the aforementioned method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy, the pressure for cold isostatic pressing in step (3) is 200 MPa, and the holding time is 10 min.

[0011] In the aforementioned method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy, the heating rate in step (4) is 5-10℃ / min, and the holding time is 3-5h.

[0012] In the aforementioned method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy, step (5) involves a total number of passes of 5-8, a single pass deformation of 30-50%, and a total deformation of no less than 85%.

[0013] The aforementioned method for preparing La2O3 particle-reinforced molybdenum-tungsten alloys involves molybdenum powder with a purity ≥99.95% and a Fisher particle size of 2-5 μm; tungsten powder with a purity ≥99.95% and a Fisher particle size of 2-5 μm; and La2O3 nanopowder with a purity ≥99.5% and an average particle size of 50-100 nm.

[0014] The present invention also provides a sintered La2O3 particle-reinforced molybdenum-tungsten alloy obtained by the aforementioned method, wherein the hardness of the sintered La2O3 particle-reinforced molybdenum-tungsten alloy is 240-275HV.

[0015] The present invention also provides a La2O3 particle-reinforced molybdenum-tungsten alloy rolled sheet obtained by the aforementioned method. After annealing at 1400℃ for 1 hour, the La2O3 particle-reinforced molybdenum-tungsten alloy rolled sheet has a tensile strength of 450-700 MPa, a yield strength of 400-650 MPa, and an elongation of 3-10%.

[0016] Compared with the prior art, the present invention has significant advantages and beneficial effects, achieving considerable technological progress and practicality, and has broad application value. It possesses at least the following advantages: (1) The La2O3 particle-reinforced molybdenum-tungsten alloy manufactured in this invention has La2O3 particles dispersed on the Mo-W matrix, which strengthens the alloy matrix and improves the hardness and strength of the alloy. At the same time, the La2O3 particles have the effect of hindering grain growth during sintering, rolling heating and recrystallization, which plays a role in grain refinement and strengthening, thereby improving the plasticity and toughness of the alloy material at the same time, and has a dual effect.

[0017] (2) This invention effectively solves the core technical pain points of traditional doping processes and overcomes the problem of difficult dispersion of nanoparticles. In the prior art, when nano-La2O3 is directly doped into Mo-W alloys, although La2O3 is nanoscale, there are still a large number of soft agglomerates in the powder. Due to the large density difference between La2O3 and Mo and W powders, the soft agglomerates are easily unevenly distributed, causing agglomeration. Moreover, during the sintering process, the soft agglomerates are also prone to adsorb surrounding La2O3 particles and grow into large particles, resulting in large fluctuations in alloy properties, limited strengthening effect, and even cracking during rolling. This invention adopts a "stepwise doping ball milling process". First, Mo-10%La2O3 masterbatch is prepared. Through the first ball milling (ball-to-material ratio 10:1, speed 300-400rpm), the soft agglomerates of La2O3 are dispersed. At this time, the molybdenum powder also acts as a dispersant, realizing the uniform dispersion of La2O3 in the molybdenum matrix. The Mo-10%La2O3 masterbatch was then mixed with tungsten powder and molybdenum powder in a specific ratio and subjected to a second ball milling process (ball-to-material ratio 1:1, speed 250-350 rpm). This fundamentally avoided the agglomeration and segregation problems caused by direct doping. SEM analysis showed that the La2O3 particles in the final alloy were uniformly dispersed within the grains and at the grain boundaries of the Mo-W matrix, with no obvious agglomeration or segregation. Compared with the traditional direct doping process, the uniformity of nanoparticle dispersion was significantly improved, fully leveraging the dispersion strengthening effect of La2O3.

[0018] (3) The present invention uses a pre-made masterbatch method to fully break down the soft agglomerated particles of La2O3 nanopowder, which is efficient and effective. If ball milling is used for mixing, the ball-to-powder ratio is 10:1, the amount of material processed at one time is limited, the production efficiency is low, and a large amount of molybdenum powder and tungsten powder will also be broken during ball milling, resulting in irregular shapes and hardening due to cold deformation, which is not conducive to pressing and molding. In addition, the oxygen content of molybdenum powder and tungsten powder will increase significantly during this process, which is not conducive to improving the alloy performance. Furthermore, the high ball-to-powder ratio during ball milling causes the grinding balls to collide with each other and fatigue and peel off, and the grinding debris (some of which are coarse particles of several micrometers or even tens of micrometers) enters the alloy powder, which will reduce the performance of the alloy. Although this invention may also result in such a situation, it only occurs in the production of Mo-10%La2O3 masterbatch. Mo-10%La2O3 masterbatch accounts for less than 1 / 10 of all alloy powders, and has little impact on pressing and molding and alloy performance. At the same time, only a large ball-to-material ratio needs to be used when producing Mo-10%La2O3 masterbatch, while the ball-to-material ratio is small during formal mixing. Therefore, the production efficiency is high, making it more suitable for mass production and resulting in significant economic and social benefits. Attached Figure Description

[0019] Figure 1 In the image, a and a1 are SEM images of the sintered Mo-30%W alloy obtained in Comparative Example 1 at different magnifications.

[0020] Figure 2 b and b1 are SEM images of the sintered Mo-30%W-0.25%La2O3 alloy obtained in Example 1 at different magnifications.

[0021] Figure 3 c and c1 are SEM images of the sintered Mo-30%W-0.5%La2O3 alloy obtained in Example 2 at different magnifications.

[0022] Figure 4 d and d1 are SEM images of the sintered Mo-30%W-0.75%La2O3 alloy obtained in Example 3 at different magnifications.

[0023] Figure 5 In the image, e and e1 are SEM images of the sintered Mo-30%W-1.00%La2O3 alloy obtained in Example 4 at different magnifications.

[0024] Figure 6 The values ​​are room temperature tensile curves of the alloy rolled plates obtained in Examples 1-4 and Comparative Example 1 after annealing at 1400℃ for 1 hour. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Unless otherwise specified, all conditions in the following examples were performed under standard conditions or conditions recommended by the manufacturer. Raw materials and reagents without a specified manufacturer were all commercially available products. The molybdenum powder used in the following examples had a purity ≥99.95% and a Fisher particle size of 2-5 μm; the tungsten powder had a purity ≥99.95% and a Fisher particle size of 2-5 μm; the La2O3 nanoparticles had a purity ≥99.5% and an average particle size of 50-100 nm. Unless otherwise specified, all percentages in the following examples are by mass.

[0027] Example 1 The specific steps for preparing a Mo-30%W-0.25%La2O3 alloy are as follows: (1) Place 100g of La2O3 nanopowder and 900g of molybdenum powder in a ball mill jar, add zirconium oxide grinding balls, with a ball-to-material ratio of 10:1, and ball mill at 360rpm for 24h. After completion, pass through a 200-mesh sieve to obtain 1kg of uniformly mixed Mo-10%La2O3 powder, which is the Mo-10%La2O3 masterbatch. (2) Take 50g of Mo-10%La2O3 masterbatch, 1350g of molybdenum powder and 600g of tungsten powder and put them into a ball mill jar. Add zirconium oxide grinding balls with a ball-to-material ratio of 1:1. Ball mill at 250rpm for 24h. After completion, 2kg of mixed powder with lanthanum oxide content of 0.25% is obtained. (3) Place the mixed powder obtained in step (2) into a rubber mold, select a cold isostatic press for pressing, the molding pressure is 200MPa, the holding time is 10min, and the raw blank is obtained. (4) The obtained green billet was heated to 2100℃ at 10℃ / min in an induction sintering furnace under hydrogen atmosphere and held for 5h to obtain sintered Mo-30%W-0.25%La2O3 alloy. (5) The obtained sintered Mo-30%W-0.25%La2O3 alloy was rolled at 1400℃ and rolled 6 times. The single-pass deformation was 40% and the total deformation was 95%, resulting in a 1mm thick Mo-30%W-0.25%La2O3 alloy rolled plate.

[0028] Example 2 The specific steps for preparing a Mo-30%W-0.5%La2O3 alloy are as follows: (1) Same as in Example 1, Mo-10%La2O3 masterbatch was obtained; (2) Take 100g of Mo-10%La2O3 masterbatch, 1300g of molybdenum powder and 600g of tungsten powder and put them into a ball mill jar. Add zirconium oxide grinding balls with a ball-to-material ratio of 1:1. Ball mill at 350rpm for 20h. After completion, 2kg of mixed powder with lanthanum oxide content of 0.5% is obtained. (3) Same as in Example 1, to obtain the green blank; (4) The obtained green blank was heated to 2150°C at 8°C / min in an induction sintering furnace under a hydrogen atmosphere and held for 5 hours to obtain a sintered Mo-30%W-0.5%La2O3 alloy. (5) The obtained sintered Mo-30%W-0.5%La2O3 alloy was rolled at 1400℃ and rolled 6 times. The single-pass deformation was 40% and the total deformation was 95%, resulting in a 1mm thick Mo-30%W-0.5%La2O3 alloy rolled plate.

[0029] Example 3 The specific steps for preparing a Mo-30%W-0.75%La2O3 alloy are as follows: (1) Same as in Example 1, Mo-10%La2O3 masterbatch was obtained; (2) Take 150g of Mo-10%La2O3 masterbatch, 1250g of molybdenum powder and 600g of tungsten powder and put them into a ball mill jar. Add zirconium oxide grinding balls with a ball-to-material ratio of 1:1. Ball mill at 350rpm for 24h. After completion, 2kg of mixed powder with a lanthanum oxide content of 0.75% is obtained. (3) Same as in Example 1, to obtain the green blank; (4) The obtained green blank was heated to 2150°C at 8°C / min in an induction sintering furnace under a hydrogen atmosphere and held for 5 hours to obtain a sintered Mo-30%W-0.75%La2O3 alloy. (5) The obtained sintered Mo-30%W-0.75%La2O3 alloy was rolled at 1400℃ and rolled 5 times. The single-pass deformation was 50% and the total deformation was 95%, resulting in a 1mm thick Mo-30%W-0.75%La2O3 alloy rolled plate.

[0030] Example 4 The specific steps for preparing a Mo-30%W-1.00%La2O3 alloy are as follows: (1) Same as in Example 1, Mo-10%La2O3 masterbatch was obtained; (2) Take 200g of Mo-10%La2O3 masterbatch, 1200g of molybdenum powder and 600g of tungsten powder and put them into a ball mill jar. Add zirconium oxide grinding balls with a ball-to-material ratio of 1:1. Ball mill at 350rpm for 24h. After completion, 2kg of mixed powder with lanthanum oxide content of 1.00% is obtained. (3) Same as in Example 1, to obtain the green blank; (4) The obtained green blank was heated to 2200℃ at 5℃ / min in an induction sintering furnace under hydrogen atmosphere and held for 3h to obtain sintered Mo-30%W-1.00%La2O3 alloy. (5) The obtained sintered Mo-30%W-1.00%La2O3 alloy was rolled at 1400℃ and rolled 8 times. The single-pass deformation was 30% and the total deformation was 95%, resulting in a 1mm thick Mo-30%W-1.00%La2O3 alloy rolled plate.

[0031] Comparative Example 1 The specific steps for preparing the Mo-30%W alloy are as follows: (1) Take 1400g of molybdenum powder and 600g of tungsten powder and place them in a ball mill jar. Add zirconium oxide grinding balls with a ball-to-material ratio of 1:1. Mill at 350rpm for 24h. After completion, 2kg of molybdenum-tungsten mixed powder (lanthanum oxide content is 0) is obtained. (3) The obtained molybdenum-tungsten mixed powder is placed in a rubber mold and pressed by a cold isostatic press. The molding pressure is 200 MPa and the holding time is 10 min to obtain the blank. (4) The obtained green billet was heated to 2100℃ at 8℃ / min in an induction sintering furnace under hydrogen atmosphere and held for 5h to obtain sintered Mo-30%W alloy. (5) The obtained sintered Mo-30%W alloy was rolled at 1400℃ and rolled 8 times, with a single-pass deformation of 30% and a total deformation of 95%, to obtain a 1mm thick Mo-30%W alloy rolled plate.

[0032] The sintered Mo-30%W-xLa2O3 alloys (x = 0.25%, 0.5%, 0.75%, and 1.00%, respectively) prepared in step (4) of Examples 1-4 and the sintered Mo-30%W alloys prepared in step (4) of Comparative Example 1 (hereinafter referred to as "sintered molybdenum-tungsten alloys") were subjected to Vickers hardness tests, and the results are shown in Table 1.

[0033] Table 1. Hardness test results of sintered molybdenum-tungsten alloys prepared in Examples 1-4 and Comparative Example 1, step (4). Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Hardness / HV 242.11 251.06 269.63 240.88 233.42 As shown in Table 1, compared with Comparative Example 1, the hardness of the sintered molybdenum-tungsten alloy with added lanthanum oxide particles was significantly improved after treatment by the methods of Examples 1-4 of the present invention.

[0034] Figure 1 In the image, a and a1 are SEM images of the sintered Mo-30%W alloy obtained in Comparative Example 1 at different magnifications. Figures 2-5 The images show SEM images of the sintered Mo-30%W-xLa2O3 alloys (x = 0.25%, 0.5%, 0.75%, and 1.00%) prepared in step (4) of Examples 1-4 at different magnifications. It can be seen that, compared to Comparative Example 1, the sintered Mo-30%W-xLa2O3 alloys (x = 0.25%, 0.5%, 0.75%, and 1.00%) obtained in Examples 1-4 have finer grains and a more uniform microstructure. Figures 2-5 La2O3 particles can be clearly observed dispersed on the Mo-W matrix. The vast majority of La2O3 particles are smaller than 100 nm in size, while a small portion are 100-300 nm in size. La2O3 particles can inhibit dislocation movement and grain boundary migration, thus refining the grains and increasing the hardness of the alloy material.

[0035] Figure 6 These are the room temperature tensile curves of the alloy rolled plates prepared in Examples 1-4 and Comparative Example 1 (5) after annealing at 1400℃ for 1 hour. Figure 6It can be seen that the tensile strength, yield strength, and elongation of the alloy rolled plates obtained in Examples 1-4 are all higher than those in Comparative Example 1. Comparative Example 1 underwent complete recrystallization after annealing at 1400℃, resulting in brittle fracture and almost no plasticity, while Examples 1-4 all showed obvious yield points and elongations.

[0036] Table 2 shows the mechanical properties of the alloy rolled plates obtained in Examples 1-4 and Comparative Example 1 after annealing at 1400℃ for 1 hour. As can be seen from Table 2, the Mo-30%W-0.75%La2O3 alloy rolled plate prepared in Example 3 has the highest tensile strength, yield strength, and elongation, thus exhibiting the best overall performance.

[0037] Table 2. Mechanical properties of the alloy rolled sheets obtained in Examples 1-4 and Comparative Example 1 after annealing at 1400℃ project Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Tensile strength / MPa 457.3 538.0 667.4 523.3 411.1 Yield strength / MPa 403.6 502.5 634.3 478.1 390.5 Elongation / % 3.22 4.29 9.96 3.11 0.86 The above description is merely an embodiment of the present invention and is not intended to limit the present invention in any way. The present invention can also have other embodiments based on the above structure and function, which will not be listed hereafter. Therefore, any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a La2O3 particle-reinforced molybdenum-tungsten alloy, characterized in that, Includes the following steps: (1) Molybdenum powder and La2O3 nanoparticles were mixed at a mass ratio of 9:1 and ball-milled for the first time under argon protection with a ball-to-material ratio of 10:1 to obtain Mo-10%La2O3 masterbatch. The mass percentage of La2O3 in the Mo-10%La2O3 masterbatch was 10%. (2) According to the final alloy composition of Mo-30%W-xLa2O3, take a certain amount of Mo-10%La2O3 masterbatch prepared in step (1), mix it with tungsten powder and molybdenum powder, put the mixed powder into a ball mill, control the ball-to-material ratio to be 1:1, and perform a second ball milling under argon protection to obtain mixed powder; In the Mo-30%W-xLa2O3 described in this step, the mass percentage of W is 30%, the mass percentage of La2O3 is x, the value of x is 0.1-1.0%, and the balance is Mo; (3) The mixed powder obtained in step (2) is loaded into a rubber mold and pressed into shape by cold isostatic pressing to obtain a blank; (4) The green blank obtained in step (3) is sintered in a hydrogen atmosphere at a sintering temperature of 2100℃~2200℃ to obtain a sintered La2O3 particle-reinforced molybdenum-tungsten alloy. (5) The sintered La2O3 particle-reinforced molybdenum-tungsten alloy obtained in step (4) is rolled at 1400℃ and then rolled in multiple passes to obtain La2O3 particle-reinforced molybdenum-tungsten alloy rolled sheet.

2. The method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy as described in claim 1, characterized in that, In step (1), the ball milling speed is set to 300-400 rpm and the ball milling time is 20-24 h.

3. The method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy as described in claim 1, characterized in that, In step (2), the ball milling speed is set to 250-350 rpm and the ball milling time is 20-24 h.

4. The method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy as described in claim 1, characterized in that, In step (3), the pressure for cold isostatic pressing is 200 MPa, and the holding time is 10 min.

5. The method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy as described in claim 1, characterized in that, In step (4), the heating rate is 5-10℃ / min and the holding time is 3-5h.

6. The method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy as described in claim 1, characterized in that, In step (5), the total number of passes is 5-8, the deformation per pass is 30-50%, and the total deformation is not less than 85%.

7. The method for preparing La2O3 particle-reinforced molybdenum-tungsten alloy as described in claim 1, characterized in that, The molybdenum powder has a purity of ≥99.95% and a Fisher particle size of 2-5μm; the tungsten powder has a purity of ≥99.95% and a Fisher particle size of 2-5μm; the La2O3 nanopowder has a purity of ≥99.5% and an average particle size of 50-100nm.

8. The sintered La2O3 particle-reinforced molybdenum-tungsten alloy obtained by any of the preparation methods described in claims 1-7, wherein Mo and W are used as the alloy matrix, La2O3 is dispersed in the alloy matrix, the mass percentage of La2O3 is 0.1-1.0%, the mass percentage of W is 30%, and the balance is Mo.

9. The sintered La2O3 particle-reinforced molybdenum-tungsten alloy as described in claim 8, characterized in that, The hardness of this sintered La2O3 particle-reinforced molybdenum-tungsten alloy is 240-275 HV.

10. The La2O3 particle-reinforced molybdenum-tungsten alloy rolled sheet obtained by any of the preparation methods described in claims 1-7, after annealing at 1400℃ for 1 hour, has a tensile strength of 450-700 MPa, a yield strength of 400-650 MPa, and an elongation of 3-10%.

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