Method for improving high-temperature oxidation resistance of molybdenum-rhenium alloy, product and application of product

Abstract

The invention discloses a method for improving the high-temperature oxidation resistance of a molybdenum-rhenium alloy, a product and application of the product, belongs to the field of rhenium-molybdenum high-temperature alloys, and aims to solve the problem of how to reduce segregation of impurity elements in a high-temperature environment and particularly reduce the influence of a high-temperature oxygen environment on the performance of the Mo-Re alloy. The molybdenum-rhenium alloy resistant to high-temperature oxidation comprises the following alloy elements in percentage by mass: 4.89%-4.95% of Re, 0.05%-0.11% of Zr and the balance of Mo and inevitable impurities. On the premise that the Re content is reduced, the composition design thought of alloying Mo-Re is optimized, on the basis of the Mo-5Re alloy, Zr is used for replacing part of Re, the reduction amount of the Re content is made to be equal to the adding amount of the Zr content, and finally the high-temperature oxidation resistance superior to that of the Mo-5Re alloy is obtained. Test results show that after the Re content is reduced and a trace amount of Zr is added, the oxidation resistance of the molybdenum-rhenium alloy resistant to high-temperature oxidation is superior to that of a Mo-5Re alloy, and a large amount of segregation of oxides basically does not occur at the grain boundary.

Description

Technical Field

[0001] This invention relates to the field of metallic materials, particularly high-temperature alloys, specifically a method, product, and application for improving the high-temperature oxidation resistance of molybdenum-rhenium alloys. Background Technology

[0002] (I) Introduction to Mo-Re alloys.

[0003] Molybdenum (Mo), a refractory metal, possesses advantages such as a high melting point, excellent thermophysical properties, high hardness, superior high-temperature mechanical strength, low coefficient of thermal expansion, and good thermal and electrical conductivity, making it widely used in the electronics, aerospace, and energy industries. Molybdenum has a melting point as high as 2720℃ and exhibits good high-temperature tensile strength above 1000℃, thus becoming an important candidate material for high-temperature alloys. However, due to its typical body-centered cubic structure, molybdenum suffers from drawbacks such as room-temperature brittleness, poor processing performance, low recrystallization temperature, and susceptibility to oxidation. Currently, various methods exist to improve the low-temperature brittleness of molybdenum, including controlling impurity elements, improving heat treatment processes, and adding alloying elements to improve the grain size and phase composition of the metal. Among these, adding alloying elements, especially rhenium (Re), is considered one of the most effective methods to improve the low-temperature brittleness of molybdenum.

[0004] Re is currently considered the most effective alloying element for improving the room temperature brittleness and processing performance of Mo. Adding Re to Mo can improve the plasticity and strength of metallic Mo, and while significantly reducing the ductile-brittle transition temperature (DBTT) of Mo, it can increase the recrystallization temperature, thereby obtaining excellent low-temperature and high-temperature mechanical properties. The addition of Re also weakens anisotropy and improves the processing performance and thermophysical properties of molybdenum alloys. The changes in the physicochemical properties of metallic molybdenum caused by the addition of rhenium are called the "rhenium effect". The reasons for the formation of the "rhenium effect" are usually summarized as follows: (1) Rhenium can form MoReO4 type compounds with molybdenum, which are different from MO2 type compounds and do not wet the grain boundaries; (2) Rhenium can increase the solubility of C and O, making it difficult for carbides and oxides to precipitate; (3) Molybdenum-rhenium alloys undergo twinning deformation during low-temperature deformation, which is different from pure metallic molybdenum; (4) Rhenium changes the electronic structure of molybdenum, reduces the direction of atomic bonds, reduces the stacking fault energy, and increases the shear modulus.

[0005] Studies have shown that molybdenum alloys based on Mo with added 2%–5% Re can improve the low-temperature brittleness of Mo, thereby enhancing its processing and welding properties. They also maintain good ductility while increasing strength, classifying them as solid-solution strengthened alloys. When the Re content is around 14%, the elongation of the Mo-Re alloy approaches 40%, exhibiting the best processing performance, while simultaneously demonstrating a certain degree of solid-solution strengthening effect from Re. Mo-14Re alloys are widely used as structural materials in international space power systems. When the Re content increases to 35%, its rolling deformation at room temperature can reach 90%. Therefore, the room-temperature tensile strength, ductility, and resistivity of molybdenum-rhenium alloys increase with increasing rhenium content. Mo-50%Re is generally used as a high-temperature structural material. Mo-5%Re and Mo-41%Re are commonly used as thermocouple wires and structural materials in aerospace applications, while Mo-50%Re is generally used for high-temperature structural applications. Furthermore, research indicates that high-Re-content Mo-Re alloys with added rare earth elements also possess excellent comprehensive mechanical properties.

[0006] (II) Design and application of molybdenum-rhenium alloy composition.

[0007] Mo crystals have a body-centered cubic structure, while Re has a close-packed hexagonal structure. Re dissolves in Mo to form a body-centered cubic α phase, with a maximum solid solubility of 39% (mass fraction) at room temperature. With further increases in Re content, intermetallic compounds of δ and χ phases will appear in the alloy system. These compounds are brittle phases and easily degrade material properties. However, actual alloy preparation processes are usually conducted under non-absolute equilibrium conditions, and the Re mass fraction is typically controlled below 50% to obtain superior overall mechanical properties. It is generally believed that as the Re content increases, the solid solution strengthening effect of Re in Mo improves, the Re effect increases, and the strength and plasticity of Mo-Re alloys will increase accordingly. Until the Re mass fraction reaches approximately 50%, the precipitation of δ and χ phases leads to a decrease in material plasticity.

[0008] To maximize the utilization of the rhenium effect, Mo-Re alloys initially had high Re content. Mo-41Re and Mo-47.5Re (Mo-50Re) were the first molybdenum-rhenium alloys to be developed. In the 1960s, the United States was the first to mass-produce these two alloys for use in the manufacture of thermocouple sheaths and vacuum heat-resistant components. Subsequently, Russia, the United States, and other countries began to consider these two alloys as cladding materials, and systematic studies were conducted on their thermophysical properties, fracture properties, alkali metal corrosion, and neutron irradiation characteristics. Currently, Mo-Re alloys used on a large scale are mainly concentrated in Mo-Re alloys with a Re mass fraction of 30.0% to 47.5%.

[0009] Meanwhile, the United States researched and developed several space power systems suitable for use on lunar bases, with typical examples including the SNAP-8 series proposed in 1967 and the SP-100 Brayton Energy system proposed between 1991 and 1993. Entering the 21st century, the United States significantly accelerated the development of power systems for planetary surfaces, successively proposing dozens of planetary surface power system designs, including SAFE-400, SAIRS, HP-STMCs, SCoRe, S4, MRS, HOMER.SUSEE, AFSPS, and LEGO-LRCS. These power system designs widely utilize molybdenum-rhenium (Mo-Re) alloys as structural materials. In the SAFE-400 power system design, the body material is pure Mo metal, and the heat pipe material is Mo-44Re alloy.

[0010] Furthermore, molybdenum alloys with 2%–5% rhenium added to molybdenum can improve the low-temperature brittleness of molybdenum, thereby enhancing its processing and welding properties. They maintain good ductility while increasing strength, classifying them as solid-solution strengthened alloys. When the rhenium content is around 14%, the Mo-Re alloy exhibits an elongation close to 40% and the best processing performance, while also possessing a certain degree of solid-solution strengthening effect from Re. The Mo-14Re alloy is used in the casing, heat pipes, and body materials of HP-STMCs ​​power supplies in the United States.

[0011] Although Re significantly enhances the properties of Mo-Re alloys, Re metal resources are extremely scarce and expensive. Therefore, reducing the Re content in Mo-Re alloys is of great value for industrial applications. However, as the Re content decreases, the "Re effect" gradually weakens, and its strengthening effect (especially the improvement in plasticity) becomes less significant. Therefore, how to achieve the strengthening and toughening effect of high Re content at a lower Re content has become a challenge in the composition design of Mo-Re alloys.

[0012] (III) High-temperature oxidation resistance of Mo-Re alloy.

[0013] Neither pure molybdenum nor pure rhenium exhibits good oxidation resistance above 300°C. Pure metallic rhenium begins to oxidize to Re₂O₇ when heated to above 160°C in air; above 360°C, Re₂O₇ volatilizes, accelerating oxidation. Mo begins to oxidize when heated to above 300°C in air; above 600°C, the generated MoO₃ volatilizes violently in air. Mo-Re alloys also have weak oxidation resistance; after holding at 300°C in air for 2 hours, MoO₃ and Mo₈O₃ begin to form on the alloy surface. 23 The mixed oxidation products rapidly oxidized on the surface after being kept at 600℃ for 2 hours, forming a thick and loose oxide layer, which was also composed mainly of MoO3 and Mo8O. 23As a result, Mo-Re alloys are difficult to operate in air environments above 600°C without the protection of an anti-oxidation coating.

[0014] High-temperature structural materials typically operate under low oxygen partial pressure conditions protected by vacuum or inert gas. Studies on the oxidation behavior of Mo-41Re under low oxygen partial pressure conditions revealed that at 10... -3 ~10 -4 After holding at a dynamic vacuum of 10 Pa for 500 h, the Mo-41Re alloy showed a slight increase in mass. The increase in mass with increasing holding temperature was very minor, which is closely related to the formation of a stable MoO film on the surface. When the vacuum level decreased to 10 Pa... -2 At 800℃, the material exhibited significant weight loss, which is related to the generation of volatile MoO3. However, neither weight gain nor loss had any impact on the tensile strength of the material after oxidation, further confirming that the Mo-Re alloy did not undergo internal oxidation in a low-oxygen environment; oxygen corrosion of the material was mainly concentrated on the shallow surface. Research data shows that the uncoated Mo-Re alloy, under a vacuum of 10... -4 Under Pa conditions, it can operate up to 900℃ without oxidation or weight loss; under Ar atmosphere conditions, the vacuum level can be controlled at 5×10⁻⁶. -6 ~10×10 -6 The material can withstand a maximum service temperature of 800℃.

[0015] Regardless of whether the oxidation is in a low-oxygen or high-oxygen environment, the outer oxide products of Mo-Re alloys are mainly molybdenum, with very little Re oxide. Calculations of the Gibbs free energies for Mo-O and Re-O reactions at 600–1000 °C revealed that the Gibbs free energies for all Re-O reactions are greater than those for the Mo-O reaction. Therefore, during alloy oxidation, O will adsorb onto the alloy surface and preferentially react with Mo. As the oxide layer thickens, the molybdenum-based solid solution in contact with the oxide layer will become enriched in Re, leading to the precipitation of new χ and δ phases in the inner layer.

[0016] Below 1000℃, there is no need to consider the oxidation problem of Mo-Re alloys. However, if Mo-Re alloys are used as structural materials in high-temperature heat pipes, they are generally used in deep space exploration, space surface energy and other outer space applications, where the operating temperature is above 1000℃. When high-temperature heat pipes are tested or launched on the ground, accidents may occur, causing the system to lose its airtightness. This exposes the Mo-Re alloy to the high-temperature air environment, posing a great risk of oxidation failure. Therefore, improving the high-temperature oxidation resistance of molybdenum-rhenium alloys is extremely important for their application in high-temperature environments.

[0017] Prolonged high-temperature operation can lead to aging weakening or embrittlement of materials. It is noteworthy that Mo-Re alloys, under prolonged high temperatures, exhibit grain coarsening and segregation of O and N impurities at grain boundaries, resulting in reduced tensile strength and increased embrittlement, severely limiting their reliability and service life. Furthermore, irradiation of Mo-Re alloys accelerates the segregation of O and N impurities and transmutation products at grain boundaries. Research from Oak Ridge National Laboratory in the United States indicates that at irradiation temperatures above 1100 K, even at low doses, severe irradiation embrittlement and intergranular fracture occur with increasing temperature. This high-temperature embrittlement may be caused by irradiation-induced Re transmutation and irradiation-induced precipitates. Therefore, when improving the high-temperature oxidation resistance of molybdenum-rhenium alloys, it is essential to select alloys with appropriate rhenium content.

[0018] (iv) Preparation process of molybdenum-rhenium alloy.

[0019] The main technologies for preparing molybdenum-rhenium alloys include powder metallurgy and electric arc melting.

[0020] Powder metallurgy is the most common method for preparing molybdenum-rhenium alloy ingots. First, molybdenum powder and rhenium powder are mixed evenly, then molded or isostatically pressed, followed by pre-sintering and high-temperature sintering at above 2000℃ to produce a molybdenum-rhenium alloy with a relative density of approximately 90%. The purity of the molybdenum powder used in preparing the alloy is generally not less than 99.95%, and the purity of the rhenium powder is generally not less than 99.98%, with an average particle size of less than 5μm. Another powder metallurgy method for preparing molybdenum-rhenium alloys is medium-temperature sintering. Compared to the above method, the difference lies primarily in the raw materials used. This method uses MO3 and NH4ReO4, which are mixed and co-reduced to prepare molybdenum-rhenium alloy powder. This powder is then pressed, pre-sintered, and sintered at a medium temperature of 1700℃ to produce a rhenium-molybdenum alloy ingot. The process of preparing molybdenum-rhenium alloys using powder metallurgy is simple and low-cost, but the impurity content of the ingots is often high. When the rhenium content is high, the alloy ingots are also prone to forming brittle σ phases.

[0021] To overcome the above shortcomings, vacuum melting purification technology was applied to the preparation of molybdenum-rhenium alloys. Compared with other methods, vacuum melting produces molybdenum-rhenium alloy ingots with lower impurity content, especially a significant reduction in gaseous elements, and the second phase is less likely to precipitate, all of which are beneficial for subsequent processing of molybdenum-rhenium alloys. However, the grains of molybdenum-rhenium alloy ingots prepared by this method are usually very coarse, which is not conducive to the blanking of the alloy. Mo-41Re materials were prepared by using both powder metallurgy and melting methods. It was found that the molybdenum-rhenium alloy prepared by melting method had lower oxygen content but coarse grains. The material prepared by powder metallurgy method had fine grains, and the internal pores could be removed by large deformation, resulting in better tensile strength and plasticity. The two preparation methods had little effect on the elastic modulus.

[0022] Therefore, powder metallurgy has advantages such as simple process flow, highly adjustable process parameters, and high material utilization. However, molybdenum-rhenium alloys prepared by arc melting exhibit better purification and higher density. Although powder metallurgy has become the main technical route for the industrial production of refractory metal materials, alloys prepared by melting methods have fewer impurities and larger grains, which can more clearly reflect changes in microstructure. When studying the high-temperature oxidation behavior of molybdenum-rhenium alloys, alloy samples prepared by melting methods are more advantageous for characterizing oxides and segregated phases at grain boundaries.

[0023] In summary, reducing the segregation of impurity elements, especially the impact of high-temperature oxygen environments, on the properties of Mo-Re alloys is a key challenge in Mo-Re alloy composition design. Therefore, there is an urgent need to develop a high-temperature oxidation-resistant molybdenum-rhenium alloy that combines excellent performance with promising applications. Summary of the Invention

[0024] The technical problem to be solved by this invention is how to reduce the segregation of impurity elements and the influence of high-temperature oxygen environment on the performance of Mo-Re alloys under high temperature environment. This is a difficult point in the composition design of Mo-Re alloys. To this end, this application provides a method, product and application for improving the high-temperature oxidation resistance of molybdenum-rhenium alloys.

[0025] Resin (re) metal resources are extremely scarce and expensive. Reducing the Re content in Mo-Re alloys is of great value for industrial applications. However, as the Re content decreases, the "Re effect" gradually weakens, and its strengthening effect, especially the improvement in plasticity, becomes less significant, greatly limiting the further development of molybdenum-rhenium alloys in industrial applications. Therefore, how to achieve and optimize the alloy properties at the original Re content while reducing the Re content is a challenge in the composition design of Mo-Re alloys.

[0026] This invention improves the alloying composition design of Mo-Re while reducing the Re content. Based on the Mo-5Re alloy, Zr is used to replace part of the Re, and the reduction in Re content is equal to the addition of Zr content, ultimately resulting in high-temperature oxidation resistance that surpasses that of the Mo-5Re alloy.

[0027] To achieve the above objectives, the present invention adopts the following technical solution.

[0028] A method for improving the high-temperature oxidation resistance of molybdenum-rhenium alloys involves replacing part of the Re element with Zr element based on Mo-5Re alloy to improve the high-temperature oxidation resistance of Mo-5Re alloy.

[0029] The mass percentage of Zr used is 0.05%~0.11%.

[0030] Zr is used to replace part of the Re element, and the mass percentage of Zr in the alloy is the same as the mass percentage of the replaced Re element in the alloy.

[0031] In this alloy, the sum of the mass percentages of Zr and Re is 5.00%.

[0032] The balance is Mo and unavoidable impurities.

[0033] Application of the aforementioned methods for improving the high-temperature oxidation resistance of molybdenum-rhenium alloys.

[0034] This method was used to improve the high-temperature oxidation resistance of Mo-5Re alloys.

[0035] A molybdenum-rhenium alloy resistant to high-temperature oxidation, wherein the mass percentages of each alloying element are as follows: 4.89-4.95% Re, 0.05-0.11% Zr, with the balance being Mo and unavoidable impurities.

[0036] In this alloy, the sum of the mass percentages of Zr and Re is 5.00%.

[0037] The mass percentages of each alloying element are as follows: 4.94% Re, 0.06% Zr, with the balance being Mo and unavoidable impurities.

[0038] The mass percentages of each alloying element are as follows: 4.92% Re, 0.08% Zr, with the balance being Mo and unavoidable impurities.

[0039] The mass percentages of each alloying element are as follows: 4.90% Re, 0.10% Zr, with the balance being Mo and unavoidable impurities.

[0040] The Mo powder has a purity ≥ 99.95% and a particle size of 325 mesh; the rhenium powder has a purity ≥ 99.99% and a particle size of 325 mesh; the Zr powder has a purity ≥ 99.95% and a particle size of 325 mesh.

[0041] The aforementioned high-temperature oxidation-resistant molybdenum-rhenium alloy is prepared by a method comprising the following steps:

[0042] Step 1: Mixing and Preparing Flour

[0043] Weigh out Mo powder, Re powder, and Zr powder according to the specified ratio, and mix them evenly in a mixer. During mixing, a protective gas is introduced, and the mixing time is 12-24 hours. The evenly mixed powder is then quantitatively distributed to obtain the first raw material.

[0044] Step 2, Send powder

[0045] The first raw material obtained in step 1 is fed into and filled into the high-throughput melting position of the vacuum arc melting furnace;

[0046] Step 3: Vacuum melting

[0047] After step 2 is completed, the first raw material in the high-throughput melting position is subjected to arc melting in a vacuum arc melting furnace with a vacuum degree of 10. -4 ~10 -5 Pa, to obtain the ingot;

[0048] Step 4, Heat Treatment

[0049] The ingot obtained after melting in step 3 is annealed at a temperature of 800~1000℃ for a duration not exceeding 2.5h.

[0050] In step 1, the protective gas is argon.

[0051] In step 4, the annealing time is 0.5~2.5h.

[0052] In step 1, Mo powder, Re powder, and Zr powder are weighed according to the ratio and mixed evenly in a mixer. The total amount of powder mixed in each batch is 4.0~4.1 kg, and the mixing time is 1224h. The powder mixed in each batch is quantitatively distributed to obtain the first raw material.

[0053] Each batch of mixed powder was quantitatively allocated, with 160~170g of raw material for preparing a single high-throughput sample of molybdenum-rhenium alloy resistant to high-temperature oxidation. This raw material was designated as the first raw material.

[0054] In step 1, the high-throughput melting stations of the vacuum arc melting furnace are 1 to 100.

[0055] The aforementioned applications of molybdenum-rhenium alloys resistant to high-temperature oxidation.

[0056] This molybdenum-rhenium alloy was used as a high-temperature oxidation resistant alloy.

[0057] This molybdenum-rhenium alloy will be used in the aerospace, electronics, and energy industries.

[0058] As mentioned earlier, Mo-Re alloys possess excellent mechanical properties, machinability, high-temperature resistance, and corrosion resistance, making them promising for applications in aerospace, electronics, high-temperature environments, and electric light sources. However, the high price of rhenium limits their widespread application, necessitating the development of high-performance low-rhenium alloys. Meanwhile, molybdenum-rhenium alloys are among the best candidate materials for reactor core structures in space nuclear power sources. Improving the performance of low-rhenium alloys like Mo-5Re and reducing manufacturing costs is crucial for the industrial application of rhenium-molybdenum alloys. Therefore, this application provides a method, product, and application for improving the high-temperature oxidation resistance of molybdenum-rhenium alloys. In a specific example, it is a low-rhenium-content molybdenum-rhenium alloy composition, with the following mass percentages of major alloying elements: Re: 4.89~4.95%; Zr: 0.05%~0.11%; balance being Mo and unavoidable impurities. Preferably, the mass percentages of major alloying elements are as follows: Re: 4.94%; Zr: 0.06%; balance being Mo and unavoidable impurities. Preferably, the mass percentages of the major alloying elements are as follows: Re: 4.92%; Zr: 0.08%; the balance being Mo and unavoidable impurities. Preferably, the mass percentages of the major alloying elements are as follows: Re: 4.90%; Zr: 0.10%; the balance being Mo and unavoidable impurities.

[0059] This invention, while reducing the Re content in Mo-5Re alloys, replaces part of the Re with Zr, ensuring that the reduction in Re content equals the increase in Zr content. This significantly enhances the oxidation resistance of Mo-Re alloys in high-temperature oxygen environments, maintaining and surpassing other properties of the original alloy, demonstrating significant advancement. Furthermore, by utilizing existing Mo-5Re alloy production processes, it meets the demands of industrial-scale, mass production, and has high application value and promising prospects in aerospace, electronics, and energy industries.

[0060] Compared with existing technologies, this invention adjusts the alloy composition to provide a molybdenum-rhenium alloy resistant to high-temperature oxidation. Compared with existing Mo-5Re alloys, this invention has the following advantages and beneficial effects:

[0061] (1) After reducing the Re content and adding trace amounts of Zr, the oxidation resistance of the molybdenum-rhenium alloy resisting high temperature oxidation of the present invention surpasses that of the Mo-5Re alloy, and there is basically no large amount of oxide segregation at the grain boundaries.

[0062] (2) Compared with the Mo-5Re alloy, the high-temperature oxidation resistant molybdenum rhenium alloy of the present invention has a grain size that is 79% smaller than that of the Mo-5Re alloy, which is of significant progress.

[0063] (3) Based on the existing Mo-5Re alloy, this invention can prepare a rhenium-molybdenum alloy that is resistant to high temperature oxidation by adding a trace amount of Zr to replace the Re element. The existing production process of Mo-5Re alloy can be used, which can meet the needs of industrialization, large-scale and batch production. It has high application value and good application prospects. Attached Figure Description

[0064] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0065] Figure 1 The images show the microstructure of each embodiment under high temperature and oxygen conditions.

[0066] Figure 2 This is a microstructure diagram of the Mo-5Re alloy under high temperature and oxygen conditions.

[0067] Figure 3 These are ZrO2 particles formed within the matrix of Example 1.

[0068] Figure 4 These are ZrO2 particles formed within the matrix of Example 2.

[0069] Figure 5 These are ZrO2 particles formed within the matrix of Example 3.

[0070] Figure 6 This is a schematic diagram of a high-throughput tensile specimen. Detailed Implementation

[0071] The following description is intended to disclose the invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0072] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0073] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0074] It should be noted that the terms "comprising" or "may include" used in the various embodiments of this application indicate the presence of the claimed function, operation, or element, and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in the various embodiments of this application, the terms "comprising," "having," and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or adding one or more combinations of the foregoing.

[0075] In various embodiments of this application, the expression "or" or "at least one of B and / or C" includes any combination or all combinations of the words listed simultaneously. For example, the expression "B or C" or "at least one of B and / or C" may include B, may include C, or may include both B and C.

[0076] It should be understood that terms such as "first," "second," "third,"..."seventh" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," "third,"..."seventh" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Unless the context clearly indicates an exception, words such as "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list; the method or apparatus may also include other steps or elements.

[0077] The present invention will be described in detail below with reference to specific embodiments. Unless otherwise specified, all conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Raw materials and reagents whose manufacturers are not specified are all commercially available products.

[0078] (a) Sample preparation Example 1

[0079] In this embodiment, the composition and mass percentage of the high-temperature oxidation-resistant molybdenum-rhenium alloy used are as follows: 4.94% Re, 0.06% Zr, with the balance being Mo and unavoidable impurities.

[0080] The above-mentioned method for preparing the high-temperature oxidation-resistant molybdenum-rhenium alloy includes the following steps.

[0081] Step 1: Powder Mixing and Preparation: Mo powder, Re powder, and Zr powder are placed in a mixer according to the specified ratio and mixed evenly. A protective gas (such as argon) is introduced. The total mass of the mixed powder is 4.0 kg, and the mixing time is 12 h. The mixed powder is then quantitatively distributed, with 160 g of raw material used for preparing a single high-throughput sample of molybdenum-rhenium alloy resistant to high-temperature oxidation.

[0082] Step 2, Powder Feeding: The raw materials are fed into and filled into the 24 high-throughput melting positions of the vacuum arc melting furnace. The vacuum arc melting furnace has 3 rows of high-throughput melting positions, with 8 positions in each row, for a total of 24 melting positions.

[0083] Step 3, Vacuum Melting: The raw materials in the high-throughput melting position are melted by electric arc in a vacuum arc melting furnace with a vacuum degree of 10. -4 Pa.

[0084] Step 4, heat treatment: The high-throughput ingot after melting is annealed at 800℃ for 1.5 hours to obtain molybdenum-rhenium alloy. Example 2

[0085] In this embodiment, the composition and mass percentage of the high-temperature oxidation-resistant molybdenum-rhenium alloy used are as follows: 4.92% Re, 0.08% Zr, with the balance being Mo and unavoidable impurities.

[0086] The above-mentioned method for preparing the high-temperature oxidation-resistant molybdenum-rhenium alloy includes the following steps.

[0087] Step 1: Powder Mixing and Preparation: Mo powder, Re powder, and Zr powder are placed in a mixer according to the specified ratio and mixed evenly. A protective gas (such as argon) is introduced. The total amount of powder to be mixed is 4.0 kg, and the mixing time is 18 h. The mixed powder is then quantitatively distributed, with 165 g of raw material used for preparing a single high-throughput sample of molybdenum-rhenium alloy resistant to high-temperature oxidation.

[0088] Step 2, Powder feeding: Feed the raw materials into and fill the 24 high-throughput melting positions of the vacuum arc melting furnace.

[0089] Step 3, Vacuum Melting: The raw materials in the high-throughput melting position are melted by electric arc in a vacuum arc melting furnace with a vacuum degree of 10. -5 Pa.

[0090] Step 4, heat treatment: The high-throughput ingot after melting is annealed at 900℃ for 2 hours to obtain molybdenum-rhenium alloy. Example 3

[0091] In this embodiment, the composition and mass percentage of the high-temperature oxidation-resistant molybdenum-rhenium alloy used are as follows: 4.90% Re, 0.10% Zr, with the balance being Mo and unavoidable impurities.

[0092] The above-mentioned method for preparing the high-temperature oxidation-resistant molybdenum-rhenium alloy includes the following steps.

[0093] Step 1: Powder Mixing and Preparation: Mo powder, Re powder, and Zr powder are placed in a mixer according to the specified ratio and mixed evenly, with a protective gas (such as argon) purging the mixture. The total amount of powder to be mixed is 4.1 kg, and the mixing time is 24 h. The mixed powder is then quantitatively distributed, with 170 g of raw material used for preparing a single high-throughput sample of molybdenum-rhenium alloy resistant to high-temperature oxidation.

[0094] Step 2, Powder feeding: The batch-prepared raw materials are fed into and filled into the 24 high-throughput melting positions of the vacuum arc melting furnace.

[0095] Step 3, Vacuum Melting: The raw materials in the high-throughput melting position are melted by electric arc in a vacuum arc melting furnace with a vacuum degree of 10. -5 Pa;

[0096] Step 4, heat treatment: The high-throughput ingot after melting is annealed at 1000℃ for 2.5 hours to obtain molybdenum-rhenium alloy.

[0097] (ii) Performance Testing

[0098] The high-temperature oxidation resistance and room-temperature mechanical properties of the molybdenum-rhenium alloys prepared in each embodiment were tested and compared with those of the Mo-5Re alloy under the same conditions. The relevant information is as follows.

[0099] (1) Resistance to high temperature oxidation

[0100] High-temperature oxidation samples were taken from the ingot, with a sample size of φ15mm×5mm. The oxidation temperature was 1000℃, the oxygen concentration was 2000ppm, and the oxidation time was 4h. The composition, size, and grain boundary segregation of the precipitated phases in the material were characterized by SEM and the built-in EDS energy dispersive spectroscopy analyzer.

[0101] in, Figure 1 Microstructure diagrams of each embodiment under high temperature and oxygen conditions are provided. Figure 2 Microstructure diagrams of Mo-5Re alloy under high-temperature oxygen conditions are presented. Figure 1 and Figure 2Comparison reveals that in the Mo-5Re alloy, oxygen segregates at the grain boundaries, forming a large amount of MoO intergranular oxides. In contrast, no oxide segregation was observed at the grain boundaries of the high-temperature oxidation-resistant molybdenum-rhenium alloys of the various embodiments of this invention; oxygen is uniformly dispersed within the alloy matrix. Unlike the Mo-5Re alloy, oxygen forms relatively uniform ZrO2 particles within the high-temperature oxidation-resistant molybdenum-rhenium alloy matrix of the embodiments of this invention, as shown in the attached figure. Figure 3 , Figure 4 , Figure 5 As shown.

[0102] (2) Mechanical property testing

[0103] High-throughput tensile specimens were taken from the ingot. Figure 6 The sample dimensions are given; indentation samples were taken from the ingot, with a sample size of φ10mm×4mm; tensile tests were performed on the high-throughput tensile samples, the grain size of the material was characterized using a crystal phase microscope, and the hardness value of the material was tested using a nanoindenter. The test results are shown in Table 1. Table 1 shows the test results of the mechanical properties of each embodiment and Mo-5Re.

[0104] Table 1. Test results of mechanical properties of each embodiment and Mo-5Re.

[0105]

[0106] Based on the test results in Table 1, it can be seen that the mechanical properties and grain size of the high-temperature oxidation-resistant molybdenum-rhenium alloys in each embodiment of the present invention are superior to those of the Mo-5Re alloy.

[0107] Based on the above test results, it can be seen that the finished product manufactured using the high-temperature oxidation-resistant molybdenum-rhenium alloy composition of this invention not only surpasses the high-temperature oxidation resistance of Mo-5Re alloy, but also exhibits superior mechanical properties and grain size. The high-temperature oxidation-resistant molybdenum-rhenium alloy composition design concept of this invention can effectively reduce the impact of high-temperature oxygen environments on the performance of Mo-Re alloys, thereby enhancing the application value of Mo-Re alloys in special service environments.

[0108] Furthermore, this embodiment seeks protection for the application of the high-temperature oxidation-resistant molybdenum-rhenium alloy. Preferably, protection is sought for the use of this molybdenum-rhenium alloy in the aerospace, electronics, and energy industries.

[0109] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. 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's technical solution shall still fall within the scope of the present invention's technical solution.

[0110] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0111] Furthermore, this specification uses specific terms to describe embodiments thereof. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Moreover, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

[0112] Furthermore, unless expressly stated in the claims, the order of processing elements and sequences, the use of numbers and letters, or other names described in this specification are not intended to limit the order of the processes and methods described herein. Although various examples have been discussed in the foregoing disclosure of some embodiments of the invention that are currently considered useful, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments; rather, the claims are intended to cover all modifications and equivalent combinations that conform to the spirit and scope of the embodiments described herein. For example, while the system components described above can be implemented using hardware devices, they can also be implemented solely using software solutions, such as installing the described system on existing servers or mobile devices.

[0113] Similarly, it should be noted that, in order to simplify the description disclosed herein and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of embodiments in this specification may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this method of disclosure does not imply that the subject matter of this specification requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of a single embodiment disclosed above.

[0114] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this specification are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0115] For each patent, patent application, patent application publication, and other material such as articles, books, specifications, publications, and documents referenced in this specification, the entire contents of which are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this specification, as well as documents that limit the broadest scope of the claims in this specification (currently or subsequently appended to this specification). It should be noted that in the event of any inconsistency or conflict between the descriptions, definitions, and / or terminology used in the supplementary materials to this specification and the content of this specification, the descriptions, definitions, and / or terminology used in this specification shall prevail.

[0116] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. A method for improving the high-temperature oxidation resistance of molybdenum-rhenium alloys, characterized in that, Based on the Mo-5Re alloy, Zr element is used to replace part of the Re element to improve the high-temperature oxidation resistance of the Mo-5Re alloy.

2. The method for improving the high-temperature oxidation resistance of molybdenum-rhenium alloy according to claim 1, characterized in that, The mass percentage of Zr used is 0.05%~0.11%.

3. The method for improving the high-temperature oxidation resistance of molybdenum-rhenium alloy according to claim 2, characterized in that, Zr is used to replace part of the Re element, and the mass percentage of Zr in the alloy is the same as the mass percentage of the replaced Re element in the alloy.

4. The method for improving the high-temperature oxidation resistance of molybdenum-rhenium alloy according to claim 3, characterized in that, In this alloy, the sum of the mass percentages of Zr and Re is 5.00%.

5. The application of the method for improving the high-temperature oxidation resistance of molybdenum-rhenium alloy as described in any one of claims 1 to 4.

6. The application according to claim 5, characterized in that, This method was used to improve the high-temperature oxidation resistance of Mo-5Re alloys.

7. A molybdenum-rhenium alloy resistant to high-temperature oxidation, characterized in that, The mass percentages of each alloying element are as follows: 4.89-4.95% Re, 0.05-0.11% Zr, with the balance being Mo and unavoidable impurities.

8. The high-temperature oxidation-resistant molybdenum-rhenium alloy according to claim 7, characterized in that, In this alloy, the sum of the mass percentages of Zr and Re is 5.00%.

9. The high-temperature oxidation-resistant molybdenum-rhenium alloy according to claim 7 or 8, characterized in that, This molybdenum-rhenium alloy is prepared by a method including the following steps: Step 1: Mixing and Preparing Flour Weigh out Mo powder, Re powder, and Zr powder according to the specified ratio, and mix them evenly in a mixer. During mixing, a protective gas is introduced, and the mixing time is 12-24 hours. The evenly mixed powder is then quantitatively distributed to obtain the first raw material. Step 2, Send powder The first raw material obtained in step 1 is fed into and filled into the high-throughput melting position of the vacuum arc melting furnace; Step 3: Vacuum melting After step 2 is completed, the first raw material in the high-throughput melting position is subjected to arc melting in a vacuum arc melting furnace with a vacuum degree of 10. -4 ~10 -5 Pa, to obtain the ingot; Step 4, Heat Treatment The ingot obtained after melting in step 3 is annealed at a temperature of 800~1000℃ for a duration not exceeding 2.5h.

10. The application of the high-temperature oxidation-resistant molybdenum-rhenium alloy as described in any one of claims 7 to 9.

11. The application according to claim 10, characterized in that, This molybdenum-rhenium alloy was used as a high-temperature oxidation resistant alloy.

12. The application according to claim 10, characterized in that, This molybdenum-rhenium alloy will be used in the aerospace, electronics, and energy industries.

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