A molybdenum alloy and a method of making the same

Abstract

This invention provides a molybdenum alloy and its preparation method, relating to the field of powder metallurgy materials technology. The molybdenum alloy, by mass percentage, comprises the following components: rare earth element (RE): 0.045wt%-0.1wt%, zirconium salt: 0.15wt%-0.20wt%, with the balance being Mo. The preparation method of the molybdenum alloy includes: heating and stirring rare earth salts, zirconium salts, and water to obtain a mixed solution; continuously spraying the mixed solution onto the surface of stirred molybdenum oxide powder using a high-pressure spraying device to obtain a spray-coated mixed powder; drying and calcining the spray-coated mixed powder to obtain rare earth-doped molybdenum oxide powder; and reducing and sintering the rare earth-doped molybdenum oxide powder to obtain the molybdenum alloy. This invention improves the strength and plasticity of sintered molybdenum alloys, eliminating the need for subsequent plastic processing steps.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy materials technology, and in particular to a molybdenum alloy and its preparation method. Background Technology

[0002] Molybdenum is a refractory metal with a melting point as high as 2610℃. It possesses excellent thermal and electrical conductivity (room temperature thermal conductivity of approximately 138 W / (m·K)), thermal stability, and high-temperature strength. Its ability to withstand extreme conditions makes it a core candidate material for high-end fields such as electronic components (e.g., heat sinks for high-power transistors), semiconductor manufacturing (e.g., molybdenum components for ion implanters), aerospace (e.g., high-temperature guide vanes for engines), and nuclear fusion reactors (e.g., first wall protection materials). However, the application of molybdenum and traditional molybdenum alloys has long been limited by three major bottlenecks:

[0003] First, molybdenum exhibits significant intrinsic brittleness at room temperature. Molybdenum has a body-centered cubic crystal structure, resulting in few dislocation slip systems at room temperature. Furthermore, interstitial elements (O, N, C) tend to segregate at grain boundaries, forming brittle phases or weakening grain boundary bonding. Consequently, the room-temperature elongation at break of traditional sintered molybdenum alloys is typically only 3-8%, far from meeting the plasticity requirements of structural components. To improve plasticity, existing technologies require subsequent high-temperature plastic processing techniques such as forging and rolling. This not only increases the production process (usually requiring 3-5 processing steps) but also leads to a dramatic increase in energy consumption (forging temperatures need to be 1200-1500℃, consuming more than three times the energy of sintering), significantly raising production costs.

[0004] Second, the uneven distribution of reinforcing phases and poor performance stability are problems. Existing ODS (oxide dispersion strengthened) molybdenum alloys mostly employ solid-state mixing methods (such as ball milling) to add reinforcing phases like Y₂O₃ and ZrO₂. Due to the density differences between rare earth oxides and molybdenum powder (Y₂O₃ density 5.01 g / cm³, ZrO₂ density 5.89 g / cm³, Mo density 10.28 g / cm³) and particle agglomeration effects, the reinforcing phases easily form localized enrichments or agglomerates in the matrix (agglomerate particle sizes often exceeding 500 nm). This not only fails to provide dispersion strengthening but also becomes a stress concentration source, leading to large fluctuations in alloy performance (tensile strength fluctuations can reach 15-20% during mass production), making it difficult to meet the consistency requirements of high-end applications.

[0005] Third, the complexity of the process and environmental pressures. Traditional molybdenum alloy preparation requires multiple steps, including powder mixing, pressing, sintering, forging, annealing, and machining. This process is lengthy (production cycles typically exceed 72 hours), and forging is prone to defects such as cracks and uneven deformation, resulting in a yield of only 60-70%. Furthermore, some processes use rare earth metal powders or halide raw materials, which can easily generate harmful gases (such as Cl2 and NO) during production. xEnvironmental treatment costs are high; solid-phase ball milling also introduces impurities in the grinding media (such as Fe and Cr), reducing the purity of the alloy.

[0006] Currently, industry attempts to address these issues mainly focus on two directions: first, optimizing the composition ratio, such as adjusting the Y2O3 addition to 0.2-0.5%, but simple composition adjustment cannot solve the problem of strengthening phase distribution; second, improving the sintering process, such as using plasma sintering or spark plasma sintering (SPS), which can refine grains, but requires large equipment investment (a single SPS unit costs over ten million yuan), making large-scale production difficult. In addition, related technologies disclose a rare earth oxide dispersion-strengthened molybdenum alloy, which uses a co-precipitation method of ammonium molybdate and rare earth salts to prepare powder. Although this improves the mixing uniformity, the co-precipitation process requires extremely high pH control precision (error ≤ ±0.1), resulting in poor stability in industrial production. Furthermore, the alloy still requires rolling to achieve a tensile strength ≥ 500 MPa, failing to solve the subsequent processing problems.

[0007] In summary, there is an urgent need to develop a new type of molybdenum alloy and its preparation method to improve the strength and plasticity of sintered molybdenum alloys and obtain high-performance molybdenum alloys without subsequent plastic processing. Summary of the Invention

[0008] In view of this, the present invention provides a molybdenum alloy and a method for preparing the same, the main purpose of which is to improve the strength and plasticity of the sintered molybdenum alloy.

[0009] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0010] On one hand, embodiments of the present invention provide a molybdenum alloy, wherein, by mass percentage, the molybdenum alloy comprises the following components:

[0011] Rare earth element (RE): 0.045wt%-0.1wt%, Zr: 0.15wt%-0.20wt%, balance Mo.

[0012] Preferably, the rare earth element RE is Y.

[0013] Preferably, the strengthening method of the molybdenum alloy includes synergistic strengthening of nano-dispersion strengthening, grain boundary purification strengthening and grain refinement strengthening.

[0014] Preferably, the microstructure of the molybdenum alloy comprises a molybdenum matrix and a nano-reinforcing phase; wherein the nano-reinforcing phase comprises rare earth oxides RE2O3, ZrO2, and composite oxides formed by rare earth elements RE, Zr, and O; wherein the particle size of the nano-reinforcing phase is 30nm-200nm and is uniformly dispersed in the molybdenum matrix; wherein the grain size of the molybdenum matrix is ​​≤10μm.

[0015] Preferably, the molybdenum alloy has a tensile strength ≥500MPa and an elongation at break ≥30% at room temperature; wherein the molybdenum alloy is a sintered molybdenum alloy that has not undergone plastic forming.

[0016] Preferably, the density of the molybdenum alloy is ≥9.58 g / cm³. 3 .

[0017] Preferably, the method for preparing the molybdenum alloy includes the following steps:

[0018] Solid-liquid mixing step: Rare earth salt, zirconium salt and water are heated and stirred to obtain a mixed solution; the mixed solution is continuously sprayed onto the surface of the stirred molybdenum oxide powder using a high-pressure spraying device to achieve coating, and a spray-coated mixed powder is obtained.

[0019] Drying process: The mixed powder after spray coating is dried to remove moisture and obtain pretreated powder.

[0020] Calcination process: The pretreated powder is calcined to decompose rare earth salts and zirconium salts and remove organic impurities to obtain rare earth-doped molybdenum oxide powder.

[0021] Reduction treatment step: The rare earth-doped molybdenum oxide powder is subjected to reduction treatment to obtain molybdenum powder;

[0022] The sintering process involves sintering the molybdenum powder to obtain a molybdenum alloy.

[0023] Preferably, in the solid-liquid mixing step: the rare earth salt is selected from any one of anhydrous yttrium nitrate, yttrium nitrate hexahydrate, anhydrous yttrium acetate, yttrium acetate tetrahydrate, yttrium acetate trihydrate, and yttrium acetate monohydrate; the zirconium salt is selected from any one of anhydrous zirconium nitrate, zirconium nitrate tetrahydrate, zirconium nitrate pentahydrate, anhydrous zirconium acetate, zirconium acetate dihydrate, zirconium acetate tetrahydrate, and zirconium acetate monohydrate.

[0024] Preferably, in the solid-liquid mixing step: the temperature of the heating and stirring treatment is 50℃-60℃, the heating and stirring time is 40 minutes-60 minutes, and the stirring speed is ≥60 rpm.

[0025] Preferably, in the solid-liquid mixing step, the liquid-solid mass ratio of the mixed solution to the molybdenum oxide powder is 0.3-0.5:1.

[0026] Preferably, in the solid-liquid mixing step: the spray pressure of the high-pressure spray device is 0.3MPa-0.5MPa; the stirring speed in the stirring state is 100 rpm-150 rpm.

[0027] Preferably, in the drying process step: the drying temperature is 80℃-100℃, and the drying time is 2h-4h.

[0028] Preferably, in the roasting process, the roasting temperature is 400℃-500℃ and the roasting time is 1.5h-3h.

[0029] Preferably, in the reduction treatment step: the rare earth-doped molybdenum oxide powder is placed in a hydrogen atmosphere furnace, first heated to 500℃-650℃ and held for 2-3 hours, then heated to 700℃-950℃ and held for 3-5 hours, and after cooling, molybdenum powder is obtained; wherein the oxygen content in the molybdenum powder is less than 500ppm and the particle size is 400nm-900nm.

[0030] Preferably, the rare earth-doped molybdenum oxide powder is first loaded into a reduction boat and then placed in a hydrogen atmosphere furnace; wherein the thickness of the rare earth-doped molybdenum oxide powder in the reduction boat is 2mm-4mm.

[0031] Preferably, in the sintering process: molybdenum powder is loaded into a graphite mold and placed in a hot-press sintering furnace. Under a pressure of 40MPa-50MPa, the temperature is first raised to 1000℃-1100℃ and sintered for 1-2 hours, then raised to 1150℃-1350℃ and sintered for 2-3 hours, then raised to 1400℃-1600℃ and sintered for 1.5-4.5 hours, and finally raised to 2000℃-2100℃ and sintered for 4-6 hours to obtain a molybdenum alloy; wherein the heating rate is 5℃ / min-10℃ / min.

[0032] Compared with the prior art, the molybdenum alloy and its preparation method of the present invention have at least the following beneficial effects:

[0033] On one hand, embodiments of the present invention provide a molybdenum alloy, wherein, by mass percentage, the molybdenum alloy comprises the following components: rare earth elements (RE): 0.045wt%-0.1wt%, Zr: 0.15wt%-0.20wt%, with the balance being Mo. The above scheme is explained as follows: the Y and Zr elements in the molybdenum alloy of this application form rare earth oxides (e.g., Y₂O₃) and ZrO₂, both of which are high-melting-point, high-hardness ceramic phases. A precise ratio of 0.1wt%-0.045wt% rare earth elements (RE), 0.15wt%-0.20wt% Zr, and the balance being Mo forms a "dual-dispersion strengthening system." On the one hand, the nanoscale strengthening phase can effectively pin dislocation movement, increase dislocation slip resistance, and significantly improve alloy strength; on the other hand, the balanced ratio of the two avoids the decrease in plasticity caused by an excessive amount of a single strengthening phase, achieving synergistic optimization of strength and plasticity.

[0034] Furthermore, this embodiment of the invention provides a molybdenum alloy, the microstructure of which includes a molybdenum matrix and a nano-reinforcing phase; wherein the nano-reinforcing phase includes: rare earth oxides RE2O3, ZrO2, and a composite oxide formed by rare earth elements RE, Zr, and O; wherein the particle size of the nano-reinforcing phase is 30-200 nm and is uniformly dispersed in the molybdenum matrix; wherein the grain size of the molybdenum matrix is ​​≤10 μm. It should be noted that rare earth oxides (Y2O3) and ZrO2 have extremely strong adsorption capacity for interstitial oxygen (oxygen affinity is much higher than Mo), which can fix free oxygen in the matrix into a stable oxide phase, preventing oxygen segregation at grain boundaries to form a brittle MoO2 phase, significantly purifying grain boundaries and improving grain boundary bonding strength; simultaneously, the nano-reinforcing phase acts as a grain growth inhibitor, hindering grain boundary migration during sintering, maintaining a fine-grained structure of ≤10 μm in the molybdenum matrix. According to the Hall-Page relationship, the fine-grained structure can simultaneously improve the strength and plasticity of the alloy. Therefore, the molybdenum alloy provided in this embodiment achieves synergistic strengthening through nano-dispersion strengthening, grain boundary purification strengthening, and grain refinement strengthening to improve the strength and plasticity of the molybdenum alloy.

[0035] On the other hand, embodiments of the present invention provide a method for preparing a molybdenum alloy, the method comprising the following steps: heating and stirring rare earth salts, zirconium salts, and water to obtain a mixed solution; continuously spraying the mixed solution onto the surface of molybdenum oxide powder in a stirred state using a high-pressure spraying device to achieve coating, obtaining a spray-coated mixed powder; drying the spray-coated mixed powder to remove moisture, obtaining a pretreated powder; calcining the pretreated powder to decompose the rare earth salts and zirconium salts and remove organic impurities, obtaining rare earth-doped molybdenum oxide powder; reducing the rare earth-doped molybdenum oxide powder to obtain molybdenum powder; and sintering the molybdenum powder to obtain a molybdenum alloy. Here, the above scheme needs to be explained as follows: Traditional solid-phase mixing is prone to uneven distribution of reinforcing phase due to density differences and particle agglomeration. However, the present invention adopts a solid-liquid mixing method of high-pressure spraying and high-speed stirring, so that rare earth salt solution is coated on the surface of molybdenum oxide powder at the molecular scale. The Y2O3 and ZrO2 reinforcing phases formed after calcination can be uniformly dispersed in the molybdenum matrix, ensuring that each reinforcing phase particle can give full play to the dispersion strengthening effect, and providing a structural basis for high performance in the sintered state. In the subsequent reducing agent sintering step, this invention achieves the stepwise reduction of molybdenum oxide from MoO3 to MoO2 to Mo through multi-temperature reduction and gradual heating. This avoids incomplete reduction or powder agglomeration caused by single-temperature reduction, resulting in ultrafine molybdenum powder with low oxygen content and high activity. Multi-temperature sintering, through stepwise control of "preliminary densification → grain refinement → interface optimization → final densification", ensures that the alloy density meets the standard while avoiding coarse grains and agglomeration of reinforcing phases. Ultimately, it achieves excellent comprehensive performance without the need for plastic processing (e.g., forging) of the molybdenum alloy.

[0036] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0037] Figure 1 This is a microstructure diagram of the molybdenum alloy prepared in Example 1;

[0038] Figure 2 This is a microstructure diagram of the molybdenum alloy prepared in Comparative Example 1;

[0039] Figure 3 This is a microstructure diagram of the molybdenum alloy prepared in Comparative Example 2;

[0040] Figure 4 This is a microstructure diagram of the molybdenum alloy prepared in Comparative Example 3;

[0041] Figure 5 This is a microstructure diagram of the molybdenum alloy prepared in Comparative Example 4;

[0042] Figure 6 These are the tensile property curves of the molybdenum alloys prepared in Example 1 and Comparative Examples 1-3. Detailed Implementation

[0043] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0044] This invention provides a molybdenum alloy and its preparation method. Through precise composition design and innovative process synergy, the sintered molybdenum alloy directly obtains comprehensive properties of high strength and high plasticity, while simplifying the process, reducing costs, and improving industrial feasibility.

[0045] On one hand, embodiments of the present invention provide a molybdenum alloy, wherein, by mass percentage, the molybdenum alloy comprises the following components: rare earth element RE: 0.045wt%-0.1wt%, Zr: 0.15wt%-0.20wt%, with the balance being Mo and unavoidable impurities (total impurity content ≤0.1%). Preferably, the rare earth element RE is Y.

[0046] The key features of this molybdenum alloy are as follows:

[0047] (1) The strengthening methods of the molybdenum alloy include the synergistic strengthening of nano-dispersion strengthening, grain boundary purification strengthening and fine grain strengthening.

[0048] (2) The microstructure of the molybdenum alloy includes a molybdenum matrix and a nano-reinforcing phase; wherein the nano-reinforcing phase includes rare earth oxides RE2O3, ZrO2 and composite oxides formed by rare earth RE, Zr and O elements; wherein the particle size of the nano-reinforcing phase is 30nm-200nm and is uniformly dispersed in the interior and grain boundaries of the molybdenum matrix without obvious agglomeration; wherein the grain size of the molybdenum matrix is ​​≤10μm (with a uniform fine-grained structure).

[0049] (3) The nano-reinforced phase and the matrix form a tightly bonded interface structure with no cracks or voids at the interface and high bonding strength.

[0050] (4) The molybdenum alloy has a density of ≥98.5wt% and no obvious pores or inclusions.

[0051] (5) The molybdenum alloy has a tensile strength of ≥500MPa and an elongation at break of ≥30% at room temperature; wherein the molybdenum alloy is a sintered molybdenum alloy that has not undergone plastic forming.

[0052] (6) The density of the molybdenum alloy is ≥9.58 g / cm³. 3 .

[0053] On the other hand, embodiments of the present invention provide a method for preparing the above-mentioned molybdenum alloy, wherein the method for preparing the molybdenum alloy includes the following steps:

[0054] Solid-liquid mixing step: Rare earth salt, zirconium salt and water are heated and stirred to obtain a mixed solution; the mixed solution is continuously sprayed onto the surface of the stirred molybdenum oxide powder using a high-pressure spraying device to obtain a spray-coated mixed powder.

[0055] In this step, the rare earth salt is selected from any one of anhydrous yttrium nitrate (purity ≥99.0%), yttrium nitrate hexahydrate (purity ≥99.0%), anhydrous yttrium acetate (purity ≥99.0%), yttrium acetate tetrahydrate (purity ≥99.0%), yttrium acetate trihydrate (purity ≥99.0%), and yttrium acetate monohydrate (purity ≥99.0%); the zirconium salt is selected from any one of anhydrous zirconium nitrate (purity ≥99.0%), zirconium nitrate tetrahydrate (purity ≥99.0%), zirconium nitrate pentahydrate (purity ≥99.0%), anhydrous zirconium acetate (purity ≥99.0%), zirconium acetate dihydrate (purity ≥99.0%), zirconium acetate tetrahydrate (purity ≥99.0%), and zirconium acetate monohydrate (purity ≥99.0%). The purity of the molybdenum oxide powder is ≥99.9%, and the particle size is 1μm-5μm, ensuring that the raw materials are free of lumps and obvious impurities.

[0056] In this step, rare earth salts and zirconium salts are added to deionized water, with the liquid-to-solid mass ratio controlled at 0.3-0.5:1. Under constant temperature water bath heating at 50℃-60℃, the mixture is magnetically stirred at a speed of ≥60 rpm for 40-60 minutes to completely dissolve and form a transparent and uniform mixed solution. This mixed solution is then uniformly sprayed onto the surface of molybdenum oxide powder, which is being stirred at a high speed of 100-150 rpm, through a high-pressure spraying device of 0.3MPa-0.5MPa. This achieves molecular-level coating of rare earth elements on the surface of molybdenum oxide powder, preventing the agglomeration of the reinforcing phase.

[0057] Drying process: The mixed powder after spray coating is dried to remove moisture and obtain pretreated powder.

[0058] The mixed powder after spray coating is transferred to a drying device and dried with hot air (80℃-100℃, 2 hours-4 hours) to remove moisture, so as to obtain loose and uniform pretreated powder and prevent powder agglomeration that could lead to unevenness in subsequent processes.

[0059] Calcination process: The pretreated powder is calcined to decompose rare earth salts and zirconium salts and remove organic impurities to obtain rare earth-doped molybdenum oxide powder.

[0060] In this step, the pretreated powder is placed in a muffle furnace and calcined at 400℃-500℃ for 1.5-3 hours with a heating rate controlled at 5℃ / min to completely decompose the rare earth salt and zirconium salt (the rare earth salt decomposes into Y2O3 and the zirconium salt decomposes into ZrO2). At the same time, adsorbed water and organic impurities in the powder are removed to obtain rare earth-doped molybdenum oxide powder.

[0061] Reduction treatment step: The rare earth-doped molybdenum oxide powder is subjected to reduction treatment to obtain molybdenum powder.

[0062] In this process, rare earth-doped molybdenum oxide composite powder is loaded into a reduction boat, with the thickness of the material controlled at 2mm-4mm (to ensure sufficient contact with hydrogen). The boat is then placed in a hydrogen atmosphere furnace for multi-temperature reduction: first, the temperature is raised to 500℃-650℃ and held for 2-3 hours (preliminary reduction of MoO3 to MoO2), and then the temperature is raised to 700℃-950℃ and held for 3-5 hours (deep reduction of MoO2 to Mo). The hydrogen flow rate is controlled at 0.5L / min-1.0 L / min to obtain highly dispersible ultrafine molybdenum powder with low oxygen content and a particle size of 300nm-2000nm.

[0063] The molybdenum powder is sintered to obtain a molybdenum alloy.

[0064] In this step, molybdenum powder is loaded into a graphite mold and placed in a hot-press sintering furnace. Under a pressure of 40MPa-50MPa, multi-temperature sintering is carried out at a heating rate of 5℃ / min-10℃ / min: first, the temperature is raised to 1000℃-1100℃ and sintered for 1-2 hours (to achieve initial densification of the powder and eliminate porosity), then the temperature is raised to 1150℃-1350℃ and sintered for 2-3 hours (to suppress excessive grain growth and lay the foundation for uniform distribution of the strengthening phase), then the temperature is raised to 1400℃-1600℃ and sintered for 1.5-4.5 hours (to promote the bonding between the strengthening phase and the matrix interface), and finally the temperature is raised to 2000℃-2100℃ and sintered for 4-6 hours (to finally achieve high densification). The furnace is then cooled to room temperature to obtain the molybdenum alloy.

[0065] The above-described solution of the present invention is explained below:

[0066] The principle of the present invention is explained as follows:

[0067] 1) Synergistic Strengthening by Composition: The rare earth oxides (Y2O3) and ZrO2 in the molybdenum alloy of this application are both high-melting-point (Y2O3 melting point 2410℃, ZrO2 melting point 2715℃) and high-hardness ceramic phases. They are precisely proportioned with rare earth RE: 0.045wt%-0.1wt%, Zr: 0.15wt%-0.20wt%, and the balance being Mo, forming a "dual dispersion strengthening system". On the one hand, the nanoscale strengthening phase can effectively pin dislocation movement, increase dislocation slip resistance, and significantly improve the alloy strength; on the other hand, the two are in a balanced ratio, avoiding the decrease in plasticity caused by an excessive amount of a single strengthening phase, thus achieving synergistic optimization of strength and toughness.

[0068] 2) Grain boundary purification and grain refinement effect: Rare earth oxides (Y2O3) and ZrO2 have a strong adsorption capacity for interstitial oxygen (oxygen affinity is much higher than that of Mo), which can fix free oxygen in the matrix into a stable oxide phase, preventing oxygen from segregating at grain boundaries to form a brittle MoO2 phase, significantly purifying grain boundaries and improving grain boundary bonding strength; at the same time, the nano-reinforcing phase acts as a grain growth inhibitor, hindering grain boundary migration during sintering, so that the molybdenum matrix maintains a fine grain structure of ≤10μm. According to the Hall-Page relationship, the fine grain structure can simultaneously improve the strength and plasticity of the alloy.

[0069] 3) Ensuring the uniformity of solid-liquid mixing: Traditional solid-phase mixing is prone to uneven distribution of reinforcing phase due to density differences and particle agglomeration. However, this invention adopts a solid-liquid mixing method of high-pressure spraying and high-speed stirring, which allows rare earth salt solution to coat the surface of molybdenum oxide powder at the molecular scale. The Y2O3 and ZrO2 reinforcing phases formed after calcination can be uniformly dispersed in the molybdenum matrix, ensuring that each reinforcing phase particle can fully exert its dispersion strengthening effect, providing a structural basis for high performance in the sintered state.

[0070] 4) Densification and microstructure control through multi-temperature reduction: Multi-temperature reduction achieves the stepwise reduction of molybdenum oxide from MoO3 to MoO2 to Mo by gradually increasing the temperature, avoiding incomplete reduction or powder agglomeration caused by single-temperature reduction, and obtaining ultrafine molybdenum powder with low oxygen content and high activity; Multi-temperature sintering is controlled stepwise by "preliminary densification → grain refinement → interface optimization → final densification", which ensures that the alloy density is ≥98.5% and avoids coarse grains and agglomeration of strengthening phases, and finally achieves excellent comprehensive performance without forging.

[0071] The innovation of this invention is explained as follows:

[0072] 1) Precise composition optimization: This invention breaks through the limitations of traditional "adjusting composition based on experience". Through extensive research, the optimal ratio of rare earth RE: 0.045wt%-0.1wt%, Zr: 0.15wt%-0.20wt%, and the balance Mo has been determined. This ensures the strengthening effect while controlling the total amount of oxides, avoiding plasticity loss due to excessive strengthening phase. At the same time, the raw material ratio is simple and easy to control the composition in industrial production.

[0073] 2) Industrialization of solid-liquid mixing process: The high-pressure spraying device and high-speed stirring equipment used are mature equipment in the powder metallurgy industry, requiring no additional R&D investment. Moreover, the process parameters (spraying pressure, stirring speed, liquid-solid ratio) can be precisely controlled, adapting to large-scale production lines. This solves the problems of complex and poor stability of traditional co-precipitation process, and the mixing uniformity meets the standard rate of ≥95%.

[0074] 3) Forging-free process innovation: Through the synergy of composition and process, the alloy directly achieves high performance with tensile strength ≥500MPa and elongation at break ≥30% after sintering. This eliminates multiple plastic processing steps such as forging, rolling, and annealing in traditional processes, shortening the production cycle from 72 hours to less than 48 hours, reducing energy consumption by more than 40%, increasing the yield to more than 90%, significantly reducing production costs, and conforming to green manufacturing.

[0075] 4) Environmentally friendly and readily available raw materials: Yttrium nitrate, zirconium nitrate, and molybdenum oxide powder are all commercially available industrial-grade raw materials, with low procurement costs and stable supply; no harmful gas emissions are emitted during the preparation process (the roasting and decomposition products of nitrates are N2, O2, and water vapor, which are pollution-free), and the wastewater contains only a small amount of nitrates, which can meet the discharge standards after neutralization treatment, resulting in low environmental pressure and suitability for large-scale industrial production.

[0076] 5) Performance stability and compatibility: The alloy prepared by this invention has a performance fluctuation of ≤5%, which is far better than the 15%-20% of the traditional process, meeting the requirements of high-end fields for product consistency; at the same time, the sintered properties of the alloy can be adapted according to actual needs by fine-tuning the sintering temperature (2000℃-2100℃) and pressure (40MPa-50MPa), making it compatible with the performance requirements of different application scenarios.

[0077] The present invention will be further illustrated below with specific embodiments:

[0078] Example 1

[0079] This embodiment prepares a molybdenum alloy, mainly including the following steps:

[0080] Solid-liquid mixing steps: Weigh 10.2g of yttrium nitrate hexahydrate (99.5% purity), 10.5g of zirconium nitrate pentahydrate, and 1491.4g of molybdenum oxide powder by mass percentage. The raw materials are free of lumps and impurities.

[0081] Yttrium nitrate and zirconium nitrate were added to 500 mL of deionized water and heated in a constant temperature water bath at 55°C. The mixture was then magnetically stirred at 80 rpm for 50 minutes to form a transparent mixed solution. The solution was then uniformly sprayed onto the surface of molybdenum oxide powder, which was being stirred at 120 rpm, through a 0.4 MPa high-pressure spraying device to complete the coating process, resulting in a spray-coated mixed powder. The liquid-to-solid mass ratio of the mixed solution to the molybdenum oxide powder was 0.4:1.

[0082] Drying process: Place the spray-coated mixed powder in a 90℃ hot air drying oven and dry for 3 hours to obtain loose pretreated powder.

[0083] Calcination process: The pretreated powder is placed in a muffle furnace and heated to 450°C at a rate of 5°C / min. The powder is then calcined for 2 hours to obtain rare earth-doped molybdenum oxide composite powder.

[0084] Reduction process: Rare earth-doped molybdenum oxide composite powder is loaded into a reduction boat with a thickness of 3 mm and placed in a hydrogen atmosphere furnace with a hydrogen flow rate of 0.8 L / min. The temperature is first raised to 500℃ and held for 2.5 hours, then raised to 950℃ and held for 4 hours to obtain ultrafine molybdenum powder with low oxygen content.

[0085] Sintering steps: The ultrafine molybdenum powder is loaded into a graphite mold and placed in a hot press sintering furnace. Under a sintering pressure of 45 MPa and a heating rate of 8 °C / min, the temperature is first raised to 1000 °C and sintered for 1.5 hours, then raised to 1300 °C and sintered for 2.5 hours, then raised to 1600 °C and sintered for 2 hours, and finally raised to 2100 °C and sintered for 5 hours. The furnace is then cooled to room temperature to obtain the molybdenum alloy.

[0086] Among them, such as Figure 6 As shown, the molybdenum alloy prepared in this embodiment has a tensile strength of 530 MPa and an elongation at break of 38%.

[0087] In this embodiment, the molybdenum alloy prepared by mass fraction includes the following components: rare earth oxide Y: 0.094 wt%, Zr: 0.19 wt%, and the balance being Mo.

[0088] The microstructure of the molybdenum alloy prepared in this embodiment is as follows: Figure 1 As shown, it includes a molybdenum matrix and a nano-reinforcing phase; wherein the nano-reinforcing phase includes rare earth oxides Y2O3, ZrO2, and composite oxides formed by Y, Zr, and O elements; wherein the particle size of the nano-reinforcing phase is 30-200 nm and is uniformly dispersed in the molybdenum matrix; wherein the grain size of the molybdenum matrix is ​​≤10 μm.

[0089] Example 2

[0090] This embodiment prepares a molybdenum alloy, mainly including the following steps:

[0091] Solid-liquid mixing steps: Weigh 10.3g of yttrium acetate tetrahydrate, 11.4g of zirconium acetate dihydrate, and 1491.4g of molybdenum oxide powder (purity 99.9%, particle size 3μm) by mass percentage. The raw materials are free of lumps and impurities.

[0092] Yttrium acetate tetrahydrate and zirconium acetate dihydrate were added to 500 mL of deionized water and heated in a constant temperature water bath at 50 °C. The mixture was then magnetically stirred at 70 rpm for 60 minutes to form a transparent mixed solution. The solution was then uniformly sprayed onto the surface of molybdenum oxide powder, which was being stirred at 100 rpm, through a 0.3 MPa high-pressure sprayer to complete the coating process, resulting in a spray-coated mixed powder. The liquid-solid mass ratio of the mixed solution to the molybdenum oxide powder was 0.35:1.

[0093] Drying process: The mixed powder after spray coating is spray-dried to obtain loose pretreated powder.

[0094] Calcination process: The pretreated powder is placed in a muffle furnace and heated to 500°C at a rate of 5°C / min for 3 hours to obtain rare earth-doped molybdenum oxide composite powder.

[0095] Reduction process: Rare earth-doped molybdenum oxide composite powder is loaded into a reduction boat with a thickness of 2 mm and placed in a hydrogen atmosphere furnace with a hydrogen flow rate of 0.5 L / min. The temperature is first raised to 500℃ and held for 3 hours, then raised to 950℃ and held for 5 hours to obtain ultrafine molybdenum powder with low oxygen content.

[0096] Sintering steps: The ultrafine molybdenum powder is loaded into a graphite mold and placed in a hot press sintering furnace. Under a sintering pressure of 40 MPa and a heating rate of 5 °C / min, the temperature is first raised to 1000 °C and sintered for 2 hours, then raised to 1300 °C and sintered for 3 hours, then raised to 1600 °C and sintered for 2.5 hours, and finally raised to 2100 °C and sintered for 6 hours. The furnace is then cooled to room temperature to obtain the molybdenum alloy.

[0097] In this embodiment, the molybdenum alloy has a tensile strength of 530 MPa and an elongation at break of 33%.

[0098] In this embodiment, the molybdenum alloy is prepared by mass fraction as follows: Y: 0.045 wt%, Zr: 0.20 wt%, and the balance is Mo.

[0099] The microstructure of the molybdenum alloy prepared in this embodiment includes a molybdenum matrix and a nano-reinforcing phase. The nano-reinforcing phase includes rare earth oxides Y2O3, ZrO2, and composite oxides formed by Y, Zr, and O elements. The particle size of the nano-reinforcing phase is 30-200 nm and is uniformly dispersed in the molybdenum matrix. The grain size of the molybdenum matrix is ​​≤10 μm.

[0100] Comparative Example 1

[0101] Comparative Example 1 prepared a molybdenum alloy using a traditional solid-state mixing method, mainly including the following steps:

[0102] Solid-phase mixing step: Weigh 3g of Y₂O₃, 3g of ZrO₂, and 994g of molybdenum powder (99.9% purity). Add the above raw materials to a ball mill and ball mill under Ar atmosphere protection to obtain a mixed powder. The ball-to-material ratio is 10:1, the ball milling speed is 200 rpm, and the ball milling time is 10 hours.

[0103] Sintering steps: The mixed powder is loaded into a graphite mold and placed in a hot press sintering furnace. Under a sintering pressure of 45 MPa and a heating rate of 8 °C / min, the temperature is first raised to 1000 °C and sintered for 1.5 hours, then raised to 1300 °C and sintered for 2.5 hours, then raised to 1600 °C and sintered for 2 hours, and finally raised to 2100 °C and sintered for 5 hours. The furnace is then cooled to room temperature to obtain a molybdenum alloy.

[0104] Among them, such as Figure 6 As shown, the molybdenum alloy obtained in Comparative Example 1 has a room temperature tensile strength of about 470 MPa and a room temperature elongation at break of about 6%.

[0105] The microstructure of the molybdenum alloy prepared in Comparative Example 1 is shown in [reference]. Figure 2 As shown, the second phase of the molybdenum alloy prepared in Comparative Example 1 forms an agglomerated phase.

[0106] The reasons why the molybdenum alloy prepared in the embodiments of the present invention has better performance than Comparative Example 1 are explained as follows:

[0107] The microstructure of the molybdenum alloy prepared in this embodiment of the invention consists of a molybdenum matrix and nano-reinforcing phases dispersed within the matrix, wherein the nano-reinforcing phases include RE₂O₃, ZrO₂, and RE. x Zr y O (1.5x+2y) This composite oxide exhibits a coherent or semi-coherent interface between the nano-reinforcing phase and the molybdenum matrix. The nano-reinforcing phase provides dispersion strengthening by pinning dislocations and grain boundaries, and inhibits grain growth to achieve fine-grain strengthening. Simultaneously, W elements dissolved in the molybdenum matrix provide solid solution strengthening. These strengthening mechanisms synergistically enhance the alloy's strength. Furthermore, rare earth elements can adsorb and fix interstitial oxygen atoms at grain boundaries, reducing grain boundary embrittlement caused by oxygen segregation, improving grain boundary bonding strength, and inhibiting early grain boundary cracking, thereby improving the alloy's plasticity.

[0108] Compared with Comparative Example 1, which was prepared by solid-solid method, the molybdenum alloy prepared in the present invention has a more uniform distribution of the second phase and the grain boundary agglomeration phenomenon is suppressed, thus making it easier to obtain excellent strengthening and toughening effects.

[0109] Comparative Example 2

[0110] Comparative Example 2 prepared a molybdenum alloy, mainly including the following steps:

[0111] Solid-liquid mixing steps: Weigh 20.5g of yttrium nitrate hexahydrate (purity 99.5%), 22.7g of zirconium nitrate pentahydrate (purity 99.5%), and 1482.5g of molybdenum oxide powder (purity 99.9%, particle size 3μm). The raw materials are free of lumps and impurities.

[0112] Yttrium nitrate hexahydrate and zirconium nitrate pentahydrate were added to 500 mL of deionized water and heated in a constant temperature water bath at 55 °C. The mixture was then magnetically stirred at 80 rpm for 50 minutes to form a transparent mixed solution. The solution was then uniformly sprayed onto the surface of molybdenum oxide powder, which was being stirred at 120 rpm, through a 0.4 MPa high-pressure spraying device to complete the coating process, resulting in a spray-coated mixed powder. The liquid-to-solid mass ratio of the mixed solution to the waste molybdenum oxide was 0.4:1.

[0113] Drying process: Place the spray-coated mixed powder in a 90°C hot air drying oven and dry for 3 hours to obtain loose pretreated powder.

[0114] Calcination treatment: The pretreated powder is placed in a muffle furnace and heated to 450°C at a rate of 5°C / min, and calcined for 2 hours to obtain rare earth-doped molybdenum oxide composite powder.

[0115] Reduction process: Rare earth-doped molybdenum oxide composite powder is loaded into a reduction boat with a thickness of 3 mm and placed in a hydrogen atmosphere furnace with a hydrogen flow rate of 0.8 L / min. The temperature is first raised to 500℃ and held for 2.5 hours, then raised to 950℃ and held for 4 hours to obtain ultrafine molybdenum powder with low oxygen content.

[0116] Sintering steps: The ultrafine molybdenum powder is loaded into a graphite mold and placed in a hot press sintering furnace. Under the conditions of sintering pressure of 45MPa and heating rate of 8℃ / min: first heat to 1000℃ and sinter for 1.5 hours, then heat to 1300℃ and sinter for 2.5 hours, then heat to 1600℃ and sinter for 2 hours, and finally heat to 2100℃ and sinter for 5 hours. The furnace is then cooled to room temperature to obtain the molybdenum alloy.

[0117] Among them, such as Figure 6 As shown, the molybdenum alloy prepared in Comparative Example 2 has a tensile strength of over 460 MPa and an elongation at break of over 3%.

[0118] In Comparative Example 2, the molybdenum alloy prepared by mass fraction included the following components: Y: 0.29 wt%, Zr: 0.23 wt%, and the balance being Mo.

[0119] The microstructure diagram of the molybdenum alloy prepared in Comparative Example 2 is shown below. Figure 3 As shown, the second phase of the molybdenum alloy prepared in Comparative Example 2 forms an agglomerated phase. In Comparative Example 2, because the addition amounts of Y and Zr elements exceeded the critical range, the second phase particles coarsened and were prone to agglomeration at the grain boundaries, resulting in a weakening of its dispersion strengthening, grain refinement strengthening, and grain boundary purification effects. Therefore, the strengthening and toughening effects described in the embodiments of this invention could not be obtained.

[0120] Comparative Example 3

[0121] Comparative Example 3 prepared a molybdenum alloy, mainly including the following steps:

[0122] Solid-liquid mixing steps: Weigh 30.7g of yttrium nitrate hexahydrate (purity 99.5%), 34g of zirconium nitrate pentahydrate (purity 99.5%), and 1473.5g of molybdenum oxide powder (purity 99.9%, particle size 3μm). The raw materials are free of lumps and impurities.

[0123] Yttrium nitrate hexahydrate and zirconium nitrate pentahydrate were added to 500 mL of deionized water and heated in a constant temperature water bath at 55°C. The mixture was then magnetically stirred at 80 rpm for 50 minutes to form a transparent mixed solution. This mixed solution was then uniformly sprayed onto the surface of molybdenum oxide powder, which was being stirred at 120 rpm, using a 0.4 MPa high-pressure spraying device to complete the coating process, resulting in a spray-coated mixed powder. The liquid-to-solid mass ratio of the mixed solution to the waste molybdenum oxide was 0.4:1.

[0124] Drying process: Place the spray-coated mixed powder in a 90°C hot air drying oven and dry for 3 hours to obtain loose pre-treated powder.

[0125] Calcination process: The loose pretreated powder is placed in a muffle furnace and heated to 450°C at a rate of 5°C / min. The powder is then calcined for 2 hours to obtain rare earth-doped molybdenum oxide composite powder.

[0126] Reduction process: Rare earth-doped molybdenum oxide composite powder is loaded into a reduction boat with a thickness of 3 mm and placed in a hydrogen atmosphere furnace with a hydrogen flow rate of 0.8 L / min. The temperature is first raised to 500℃ and held for 2.5 hours, then raised to 950℃ and held for 4 hours to obtain ultrafine molybdenum powder with low oxygen content.

[0127] Sintering steps: Ultrafine molybdenum powder is loaded into a graphite mold and placed in a hot press sintering furnace. Under the conditions of sintering pressure of 45MPa and heating rate of 8℃ / min: first heat to 1000℃ and sinter for 1.5 hours, then heat to 1300℃ and sinter for 2.5 hours, then heat to 1600℃ and sinter for 2 hours, and finally heat to 2100℃ and sinter for 5 hours. The furnace is then cooled to room temperature to obtain a new type of high-performance sintered molybdenum alloy.

[0128] like Figure 6 As shown, the molybdenum alloy prepared in Comparative Example 3 has a tensile strength of 450 MPa and an elongation at break of more than 1%.

[0129] In Comparative Example 3, the molybdenum alloy prepared by mass fraction included the following components: Y: 0.56 wt%, Zr: 0.16 wt%, and the balance being Mo.

[0130] The microstructure of the molybdenum alloy prepared in Comparative Example 3 is shown in [reference]. Figure 4 As shown, from Figure 4 It can be seen that the second phase of the molybdenum alloy prepared in Comparative Example 3 forms an agglomerated phase. In Comparative Example 3, because the amount of Y element added far exceeds the critical range, even if the Zr element meets the requirements of the principle, the second phase is still severely coarsened and easily agglomerates at the grain boundaries, resulting in a weakening of its dispersion strengthening, grain refinement strengthening and grain boundary purification effects, and thus the toughening effect described in this invention cannot be obtained.

[0131] Comparative Example 4

[0132] Comparative Example 4 prepared a molybdenum alloy, which mainly included the following steps:

[0133] Step 1): Weigh 1820g of ammonium molybdate and place it in deionized water. Heat and stir the solution to promote dissolution and obtain a precursor solution (a uniformly mixed, clear solution). Heating is performed using a water bath at 65℃, and stirring is done with a magnetic stirrer at 120 rpm. The heating and stirring process lasts for 120 minutes.

[0134] Step 2): Add citric acid to the precursor solution to adjust the pH value to 1, heat in a water bath to 80°C to obtain the complex precursor in the solution, and then spray dry to obtain the dry powder.

[0135] Step 3): In a muffle furnace, the mixed powder is calcined at 450°C for 2 hours to obtain doped molybdenum oxide powder.

[0136] Step 4): The doped molybdenum oxide powder is placed in a hydrogen furnace and heated to 550°C and held for 2 hours, then heated to 800°C and held for 4 hours, and finally heated to 900°C and held for 4 hours for reduction treatment to obtain molybdenum powder with low oxygen content, high dispersion, and high porosity.

[0137] The thickness of the molybdenum oxide powder in the hydrogen furnace is 3 mm.

[0138] Step 5): Heat the molybdenum powder to 1000℃ and sinter for 1 hour, then raise the temperature to 1200℃ and sinter for 2 hours, then raise the temperature to 1400℃ and sinter for 1.5 hours, then raise the temperature to 1600℃ and sinter for 2 hours, and finally raise the temperature to 2100℃ and sinter for 5 hours. The sintering pressure is 40 MPa to obtain a molybdenum alloy.

[0139] The molybdenum alloy obtained in Comparative Example 4 has a tensile strength of over 440 MPa and an elongation at break of over 4%.

[0140] Among them, the molybdenum alloy prepared in Comparative Example 4 was pure molybdenum.

[0141] The microstructure of the molybdenum alloy prepared in Comparative Example 4 is as follows: Figure 5 As shown, in Comparative Example 4, due to the lack of Y and Zr elements, a uniformly dispersed nano-reinforcing phase cannot be formed in situ within the molybdenum matrix, thus lacking the dispersion strengthening effect described in the embodiments of the present invention. Simultaneously, the relevant alloying elements failed to dissolve into the molybdenum matrix, therefore also lacking the corresponding solid solution strengthening effect. Furthermore, due to the lack of pinning and inhibiting effect of the nano-second phase on grain boundaries, the molybdenum matrix is ​​more prone to grain coarsening and abnormal growth during sintering, resulting in a significantly coarser microstructure. Since the core strengthening mechanisms such as dispersion strengthening, solid solution strengthening, and grain refinement strengthening are not established, the strength and plasticity of the molybdenum alloy prepared in Comparative Example 4 are significantly lower than those in the embodiments of the present invention.

[0142] Comparative Example 5

[0143] Comparative Example 5 prepared a molybdenum alloy, mainly including the following steps:

[0144] Solid-liquid mixing steps: Weigh 10.2g of yttrium nitrate hexahydrate (99.5% purity), 10.5g of zirconium nitrate pentahydrate, and 1491.4g of molybdenum oxide powder by mass percentage. The raw materials are free of lumps and impurities.

[0145] Yttrium nitrate and zirconium nitrate were added to 500 mL of deionized water and heated in a constant temperature water bath at 55°C. The mixture was then magnetically stirred at 80 rpm for 50 minutes to form a transparent mixed solution. The solution was then uniformly sprayed onto the surface of molybdenum oxide powder, which was being stirred at 120 rpm, through a 0.4 MPa high-pressure spraying device to complete the coating process, resulting in a spray-coated mixed powder. The liquid-to-solid mass ratio of the mixed solution to the molybdenum oxide powder was 0.4:1.

[0146] Drying process: Place the spray-coated mixed powder in a 90℃ hot air drying oven and dry for 3 hours to obtain loose pretreated powder.

[0147] Calcination process: The pretreated powder is placed in a muffle furnace and heated to 450°C at a rate of 5°C / min. The powder is then calcined for 2 hours to obtain rare earth-doped molybdenum oxide composite powder.

[0148] Reduction process: Rare earth-doped molybdenum oxide composite powder is loaded into a reduction boat with a thickness of 3 mm and placed in a hydrogen atmosphere furnace with a hydrogen flow rate of 0.8 L / min. The temperature is first raised to 500℃ and held for 2.5 hours, then raised to 950℃ and held for 4 hours to obtain ultrafine molybdenum powder with low oxygen content.

[0149] Sintering steps: The ultrafine molybdenum powder is loaded into a graphite mold and placed in a hot press sintering furnace. Under a sintering pressure of 45 MPa and a heating rate of 8 °C / min, the temperature is first raised to 1000 °C and sintered for 1.5 hours, then raised to 1300 °C and sintered for 2.5 hours, then raised to 1600 °C and sintered for 2 hours, and finally raised to 1850 °C and sintered for 5 hours. The furnace is then cooled to room temperature to obtain the molybdenum alloy.

[0150] It should be noted that the sintering process defined in this application—"loading molybdenum powder into a graphite mold, placing it in a hot-press sintering furnace, and sintering at 1000℃-1100℃ for 1-2 hours under a pressure of 40MPa-50MPa, then sintering at 1150℃-1350℃ for 2-3 hours, then sintering at 1400℃-1600℃ for 1.5-4.5 hours, and finally sintering at 2000℃-2100℃ for 4-6 hours to obtain a molybdenum alloy; wherein the heating rate is 5℃ / min-10℃ / min"—is the key threshold for ensuring the densification of the internal structure of the molybdenum alloy. Because the sintering temperature in the final step of Comparative Example 5 did not meet the standard, the density of the sintered molybdenum alloy was severely insufficient, exhibiting intrinsic structural defects. During tensile deformation, these internal pores and weak bonding interfaces easily induce localized stress concentration, promoting the initiation and rapid propagation of microcracks even at relatively low stress levels. This severely hinders the intrinsic deformation capacity of the matrix, resulting in a degradation of both the yield strength and fracture elongation of the alloy, and a significant deficiency in its overall mechanical properties.

[0151] In summary, the embodiments of the present invention provide a molybdenum alloy and its preparation method. Through the synergistic effect of compositional optimization design and solid-liquid mixing process, and with the combined effect of nano-dispersion strengthening, grain boundary purification and fine grain strengthening, the molybdenum alloy can achieve excellent comprehensive properties such as room temperature tensile strength ≥500MPa and elongation at break ≥30% without plastic processing (such as forging, rolling, etc.). The process is simple, environmentally friendly, and easy to scale up, and is suitable for fields with stringent requirements for material strength and toughness, such as electronic semiconductors, aerospace, and high-end machinery.

[0152] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A molybdenum alloy, characterized in that, The molybdenum alloy is a sintered molybdenum alloy that has not undergone plastic processing; the sintered molybdenum alloy has a tensile strength ≥500MPa and an elongation at break ≥30% at room temperature; The sintered molybdenum alloy comprises the following components by mass percentage: Rare earth element (RE): 0.045wt%-0.1wt%, Zr: 0.15wt%-0.20wt%, balance Mo; wherein the rare earth element (RE) is Y; The microstructure of the sintered molybdenum alloy comprises a molybdenum matrix and a nano-reinforcing phase; wherein the nano-reinforcing phase comprises rare earth oxides RE₂O₃, ZrO₂, and composite oxides formed by rare earth elements RE, Zr, and O; wherein the particle size of the nano-reinforcing phase is 30 nm-200 nm and is uniformly dispersed in the molybdenum matrix; wherein the grain size of the molybdenum matrix is ​​≤10 μm; The method for preparing the sintered molybdenum alloy includes the following steps: Solid-liquid mixing step: Rare earth salt, zirconium salt, and water are heated and stirred to obtain a mixed solution; the mixed solution is continuously sprayed onto the surface of the stirred molybdenum oxide powder using a high-pressure spraying device to achieve coating, resulting in a spray-coated mixed powder; wherein, the spraying pressure of the high-pressure spraying device is 0.3MPa-0.5MPa; and the stirring speed during the stirring process is 100 rpm-150 rpm. Drying process: The mixed powder after spray coating is dried to remove moisture and obtain pretreated powder. Calcination step: The pretreated powder is calcined to decompose rare earth salts and zirconium salts and remove organic impurities to obtain rare earth-doped molybdenum oxide powder; wherein the calcination temperature is 400℃-500℃ and the calcination time is 1.5h-3h. Reduction treatment step: The rare earth-doped molybdenum oxide powder is reduced to obtain molybdenum powder; wherein, the rare earth-doped molybdenum oxide powder is placed in a hydrogen atmosphere furnace, first heated to 500℃-650℃ and held for 2-3 hours, then heated to 700℃-950℃ and held for 3-5 hours, and after cooling, molybdenum powder is obtained. The molybdenum powder has an oxygen content of less than 500 ppm and a particle size of 400 nm-900 nm. The sintering process involves sintering the molybdenum powder to obtain a molybdenum alloy; wherein: Molybdenum powder is loaded into a graphite mold and placed in a hot-press sintering furnace. Under a pressure of 40MPa-50MPa, the temperature is first raised to 1000℃-1100℃ and sintered for 1-2 hours, then raised to 1150℃-1350℃ and sintered for 2-3 hours, then raised to 1400℃-1600℃ and sintered for 1.5-4.5 hours, and finally raised to 2000℃-2100℃ and sintered for 4-6 hours to obtain a molybdenum alloy. The heating rate is 5℃ / min-10℃ / min.

2. The molybdenum alloy according to claim 1, characterized in that, The strengthening methods of the molybdenum alloy include synergistic strengthening of nano-dispersion strengthening, grain boundary purification strengthening, and grain refinement strengthening.

3. The molybdenum alloy according to claim 1, characterized in that, The density of the molybdenum alloy is ≥9.58 g / cm³. 3 .

4. The method for preparing the molybdenum alloy according to any one of claims 1-3, characterized in that, The preparation method of the molybdenum alloy includes the following steps: Solid-liquid mixing step: Rare earth salt, zirconium salt, and water are heated and stirred to obtain a mixed solution; the mixed solution is continuously sprayed onto the surface of the stirred molybdenum oxide powder using a high-pressure spraying device to achieve coating, resulting in a spray-coated mixed powder; wherein, the spraying pressure of the high-pressure spraying device is 0.3MPa-0.5MPa; and the stirring speed during the stirring process is 100 rpm-150 rpm. Drying process: The mixed powder after spray coating is dried to remove moisture and obtain pretreated powder. Calcination step: The pretreated powder is calcined to decompose rare earth salts and zirconium salts and remove organic impurities to obtain rare earth-doped molybdenum oxide powder; wherein the calcination temperature is 400℃-500℃ and the calcination time is 1.5h-3h. Reduction treatment step: The rare earth-doped molybdenum oxide powder is reduced to obtain molybdenum powder; wherein, the rare earth-doped molybdenum oxide powder is placed in a hydrogen atmosphere furnace, first heated to 500℃-650℃ and held for 2-3 hours, then heated to 700℃-950℃ and held for 3-5 hours, and after cooling, molybdenum powder is obtained. The molybdenum powder has an oxygen content of less than 500 ppm and a particle size of 400 nm-900 nm. The sintering process involves sintering the molybdenum powder to obtain a molybdenum alloy. Specifically, the molybdenum powder is placed in a graphite mold and then in a hot-press sintering furnace. Under a pressure of 40 MPa-50 MPa, the temperature is first raised to 1000℃-1100℃ and sintered for 1-2 hours, then raised to 1150℃-1350℃ and sintered for 2-3 hours, followed by raising to 1400℃-1600℃ and sintering for 1.5-4.5 hours, and finally raised to 2000℃-2100℃ and sintered for 4-6 hours to obtain the final molybdenum alloy. The heating rate is 5℃ / min-10℃ / min.

5. The method for preparing the molybdenum alloy according to claim 4, characterized in that, In the solid-liquid mixing step: the rare earth salt is selected from any one of anhydrous yttrium nitrate, yttrium nitrate hexahydrate, anhydrous yttrium acetate, yttrium acetate tetrahydrate, yttrium acetate trihydrate, and yttrium acetate monohydrate; the zirconium salt is selected from any one of anhydrous zirconium nitrate, zirconium nitrate tetrahydrate, zirconium nitrate pentahydrate, anhydrous zirconium acetate, zirconium acetate dihydrate, zirconium acetate tetrahydrate, and zirconium acetate monohydrate.

6. The method for preparing the molybdenum alloy according to claim 4, characterized in that, In the solid-liquid mixing step: The heating and stirring process is carried out at a temperature of 50℃-60℃, for a duration of 40-60 minutes, and at a stirring speed of ≥60 rpm.

7. The method for preparing the molybdenum alloy according to claim 4, characterized in that, In the solid-liquid mixing step, the liquid-solid mass ratio of the mixed solution to the molybdenum oxide powder is 0.3-0.5:

1.

8. The method for preparing the molybdenum alloy according to claim 4, characterized in that, In the drying process: the drying temperature is 80℃-100℃, and the drying time is 2h-4h.

9. The method for preparing the molybdenum alloy according to claim 4, characterized in that, The rare earth-doped molybdenum oxide powder is first loaded into a reduction boat and then placed in a hydrogen atmosphere furnace; wherein the thickness of the rare earth-doped molybdenum oxide powder in the reduction boat is 2mm-4mm.

Images