Preparation method of rhenium or rhenium alloy coarse grains

Abstract

The invention provides a preparation method of rhenium and rhenium alloy coarse grains, which comprises the following steps: firstly, preparing an initial sample of rhenium and rhenium alloy, carrying out deoxidation treatment, then loading the initial sample into a tool of electric arc melting equipment, starting circulating cooling water, and carrying out vacuumizing and gas washing treatment; carrying out preheating treatment and electric arc melting processing in an argon atmosphere, turning over and repeating for multiple times, and rapidly cooling along with the furnace; and finally, the sample is placed in a high-temperature furnace to be subjected to solution treatment and cooled to the room temperature along with the furnace, and the thick rhenium and rhenium alloy lamellar structure can be obtained. According to the method, the blank of rhenium and rhenium alloy coarse grain material research is filled up, the urgent demand of the academic world on rhenium and rhenium alloy coarse grains is met, and technical support is provided for anisotropy such as rhenium and rhenium alloy mechanics and corrosion irradiation; and a good raw material basis is provided for research work of deep deformation mechanisms such as rhenium and rhenium alloy microdefects. The method has the advantages of being simple in process, convenient to operate, wide in applicability, excellent in technical effect and the like.

Description

Technical Field

[0001] The invention relates to the research field of coarse crystals, rhenium and rhenium alloy materials, and in particular provides a method for preparing coarse crystals of rhenium or rhenium alloy. Background Art

[0002] In the world of metals, rhenium is a unique and precious element. Although it is rare in the earth's crust, it is unique in the field of materials science with its unique physical and chemical properties. Rhenium is one of the most refractory metals, with a melting point of up to 3180°C. It has high mechanical strength, good plasticity, excellent mechanical stability and excellent physical and chemical properties. Metal rhenium has no brittle critical transition temperature, and has good creep resistance under high temperature and rapid cooling and heating conditions, making it suitable for ultra-high temperature and strong thermal shock working environments. As a rare metal with special uses, rhenium plays an irreplaceable role in high-temperature alloys for aerospace engines and is an important strategic new material resource. 70% of the world's rhenium production is used to manufacture high-temperature alloy components for jet engines.

[0003] Rhenium is expensive, and alloys containing rhenium are often used in aerospace, energy, chemical and other application fields. Rhenium alloys mainly include W-Re, Mo-Re, W-33.3Mo-33.3Re, Mo-Re-Hf-Zr, Mo-Re-Hf-V alloys, etc. Among them, tungsten-rhenium and molybdenum-rhenium alloys are the most widely used. When rhenium is combined with metals such as tungsten and molybdenum, rhenium alloys show remarkable potential. They have high-temperature strength and corrosion resistance, which enables rhenium alloys to maintain structural and functional stability in extreme temperatures and environments. Tungsten and molybdenum have the characteristics of high strength and high hardness. When combined with rhenium, the tungsten-rhenium alloys and molybdenum-rhenium alloys formed not only maintain the original high hardness and high strength, but also obtain excellent plasticity. In addition, the high-temperature stability of tungsten-rhenium alloys and molybdenum-rhenium alloys is particularly outstanding. They can maintain structural and performance stability under extreme temperatures and pressures, and are ideal for manufacturing key components such as high-performance engines and rocket nozzles. In addition, it also shows broad application prospects in the fields of electronics, chemical industry, energy, etc.

[0004] Before the application of materials, their performance needs to be evaluated. The performance of materials is closely related to alloy composition, deformation mode, forming process, annealing system, etc., and is determined by microstructure, grain size, texture strength, micro defects, slip system activation and other factors at the micro level. Current research shows that crystal orientation has a great influence on the mechanical, corrosion, oxidation, irradiation and creep properties of rhenium and rhenium alloys. For example, when external forces are applied along different directions of the crystal, the slip system activated inside the pure rhenium crystal and the proportion of twins appearing will be significantly different, making the alloy performance anisotropic; tungsten-rhenium alloy has a body-centered cubic (BCC) structure, and its radiation damage resistance depends on the crystal plane, among which {011} has a higher radiation resistance than {100} or {111}. Crystal orientation control makes tungsten have high functionality, so the preparation of coarse grains is particularly important; materials resistant to high temperature creep also require the grains to reach a larger size or even a single crystal level. In addition, many basic research fields often urgently need coarse-grained or single-crystalline materials, such as studying the deformation mechanism of materials or macroscopic in-situ deformation research. The preparation of coarse crystals has become a major problem for scientific researchers.

[0005] However, most of the materials are polycrystalline materials at present. The preparation of coarse crystals has practical scientific value and important guiding significance for the basic research and application research of polycrystalline materials. Scholars are also looking for an effective method for preparing coarse crystals of rhenium and rhenium alloys. However, according to existing reports, there is no method for preparing coarse crystals of rhenium and rhenium alloys. Summary of the invention

[0006] In view of the shortcomings of the prior art and the urgent needs of the academic community, the present invention provides a method for preparing coarse crystals of rhenium and rhenium alloys which has simple process, easy operation, low cost and excellent technical effect.

[0007] The present invention adopts the following technical scheme: a method for preparing coarse crystals of rhenium or rhenium alloy, the preparation method specifically comprising the following steps:

[0008] S1) preparing an initial sample of rhenium or a rhenium alloy and performing a deoxidation treatment;

[0009] S2) loading the initial sample of rhenium or rhenium alloy treated in S1) into the tooling mold of the arc melting equipment, closing the furnace door, turning on the circulating cooling water, and performing a gas washing treatment after the equipment reaches a vacuum condition;

[0010] S3) preheating the initial sample of rhenium or rhenium alloy treated in S2), then arc melting it, turning it over and repeating the arc melting operation multiple times to obtain a sample of rhenium or rhenium alloy;

[0011] S4) subjecting the sample obtained in S3) to a solution treatment, and finally cooling the sample to room temperature in a furnace to obtain coarse crystals of rhenium or rhenium alloy.

[0012] Furthermore, the rhenium in S1) is pure rhenium, and the rhenium alloy is a rhenium alloy in which one or more main alloying elements of Mo, W, Ni, Zr, Hf, V, Cu, and K are added to rhenium, wherein the mass fraction of the rhenium element is 0.01% to 50%.

[0013] Further, the initial sample in S1) is a sintered blank, a deformed block, a molded blank of a single substance powder or alloy powder, and a cold isostatically pressed blank;

[0014] The deoxidation treatment includes removing the surface oxide scale, grinding and polishing, solution treatment and cleaning with acetone alcohol.

[0015] Further, the tooling mold device in S2) is made of copper alloy material, and has a water cooling device inside;

[0016] The circulating cooling water is deionized water, and the temperature of the circulating cooling water is not higher than 30°C;

[0017] The vacuum degree under the vacuum condition is not greater than 10 -2 Pa.

[0018] Further, the preheating treatment in S3) is carried out in an argon environment, and the argon pressure is -0.06 to -0.02 MPa;

[0019] During the preheating process, the arc current used is 100-220A, and the preheating time is 1-2 minutes.

[0020] Furthermore, the arc melting process in S3) is carried out in an argon environment with an argon pressure of -0.06 to -0.02 MPa; the arc current used is 320 to 460 A, and the melting time for each pass is 2 to 6 minutes.

[0021] Further, the solution treatment in S4) is carried out at 10 -3 It is carried out under vacuum conditions below Pa or under normal pressure hydrogen atmosphere;

[0022] The solution treatment temperature is 1800-2300°C and the time is not less than 6 hours.

[0023] A rhenium or rhenium alloy coarse crystal is prepared by the above-mentioned preparation method.

[0024] The beneficial effect of the present invention is that the above technical solution utilizes the direct heating vacuum arc furnace smelting method to generate an arc between electrodes or between electrodes and the smelted material to melt metal. During the smelting process in the vacuum fire inert atmosphere environment, the gas and volatile impurity content decreases. By strictly controlling the temperature, the ingot always maintains a continuous molten pool. The ingot generally does not have a loose center, which can not only ensure the uniformity of the entire ingot structure, but also effectively avoid the crystal structure from being contaminated by oxygen to form inclusions such as metal oxides, thereby improving the metal properties. In addition, adding rhenium to molybdenum-based, tungsten-based, nickel-based and other alloys can significantly improve the strength, plasticity and high-temperature stability of the alloy. However, segregation or excess of rhenium is also prone to harmful brittle precipitation phases, which is not conducive to the structural stability of the alloy. By heating the alloy to a high temperature single-phase region and maintaining a constant temperature, the excess phase is fully dissolved into the solid solution and then cooled to obtain a supersaturated solid solution. Rhenium tends to concentrate in the alloy matrix, and the formed rhenium atomic clusters are nanoscale short-range ordered atomic clusters. Subsequently, cooling with the furnace can eliminate internal stress, prevent deformation, and avoid the precipitation of brittle phases and the formation of coarse grains.

[0025] The method of the present invention fills the gap in the research of coarse-grained materials of rhenium and rhenium alloys, meets the urgent needs of the academic community for coarse-grained rhenium and rhenium alloys, provides technical support for anisotropy such as mechanics and corrosion irradiation of rhenium and rhenium alloys, and also provides a good raw material basis for the research of slip systems, critical shear stress determination, dislocations, twins and other microscopic defects of rhenium and rhenium alloys, and other deep-level deformation mechanism research. The method also has the advantages of simple process, easy operation, wide applicability and excellent technical effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The schematic diagram of the process flow for preparing coarse crystals of rhenium and rhenium alloys according to the present invention;

[0027] Figure 2 This is the metallographic microstructure diagram of the original state of the molybdenum-rhenium alloy sample in Example 1;

[0028] Figure 3 This is a macroscopic morphology of the molybdenum-rhenium alloy button ingot in Example 1;

[0029] Figure 4 is the EDS surface distribution diagram of the tungsten-rhenium alloy powder in Example 2;

[0030] Figure 5 is the SEM microstructure of the coarse grains of tungsten-rhenium alloy in Example 2;

[0031] Figure 6 is the metallographic microstructure diagram of pure rhenium coarse crystal in Example 3; DETAILED DESCRIPTION

[0032] The present invention is explained in detail below in conjunction with a number of specific embodiments. The process flow diagram of rhenium and rhenium alloy coarse crystals is shown in FIG. Figure 1 shown.

[0033] The present invention provides a method for preparing coarse crystals of rhenium and rhenium alloys, and the preparation method comprises the following steps:

[0034] (1) preparing initial samples of rhenium and rhenium alloys and performing deoxidation treatment;

[0035] (2) Loading the sample processed in step (1) into the tooling mold of the arc melting equipment, closing the furnace door, turning on the circulating cooling water, and performing a gas washing treatment after the equipment reaches a vacuum condition;

[0036] (3) preheating the sample of step (2);

[0037] (4) arc melting the sample of step (3), turning it over and repeating steps (3) and step 4 3 to 8 times;

[0038] (5) The sample of step (4) is solution treated in a high temperature furnace for a treatment time of not less than 6 hours, and then cooled to room temperature in the furnace.

[0039] As the preferred technical solution:

[0040] The rhenium and rhenium alloy described in step (1) are pure rhenium or rhenium alloys with one or more main alloying elements such as Mo, W, Ni, Zr, Hf, V, Cu, K added to rhenium, wherein the mass fraction of the rhenium element is 0.01% to 50%.

[0041] The initial samples of rhenium and rhenium alloys described in step (1) are sintered billets, deformed blocks, molded billets of single-element powder or alloy powder, and cold isostatically pressed billets.

[0042] The deoxidation treatment described in step (1) includes removing the surface oxide scale, grinding and polishing, solution treatment and cleaning with acetone and alcohol.

[0043] The tooling mold device described in step (2) is made of copper alloy material, and has a water cooling device inside to allow cooling water to circulate.

[0044] The circulating cooling water described in step (2) is deionized water, and its temperature needs to be controlled within 30°C.

[0045] The vacuum degree under the vacuum condition in step (2) is not greater than 10 -2 Pa.

[0046] The preheating treatment and arc melting process described in step (3) and step (4) are both carried out in an argon environment with an argon pressure of -0.06 to -0.02 MPa.

[0047] During the preheating process described in step (3), the arc current used is 100 to 220A and the preheating time is 1 to 2 minutes.

[0048] During the arc melting process described in step (4), the arc current used is 320 to 460 A, and the melting time for each pass is 2 to 6 minutes.

[0049] The solution treatment in step (5) is carried out at 10 -3 It is carried out under vacuum conditions below Pa or under normal pressure hydrogen atmosphere.

[0050] The solution treatment temperature in step (5) is 1800-2300°C.

[0051] Example 1

[0052] This embodiment specifically includes the following steps:

[0053] (1) The initial sample of Mo-47.5wt%Re alloy was prepared, and the sample was cut and polished, then cleaned with alcohol, and corroded with a mixed solution of nitric acid and water. The alloy state after preparation was a rolled deformation state, and the metallographic microstructure was as follows: Figure 2 As shown,

[0054] (2) Load the sample treated in step (1) into the copper alloy tooling mold of the arc melting equipment, close the furnace door, start the circulating cooling water, and wait until the equipment reaches 10 -2 Pa vacuum condition followed by gas washing;

[0055] (3) When the argon pressure reaches -0.03 MPa, the sample in step (2) is preheated for 80 seconds using an arc current of 150 A;

[0056] (4) arc melting the sample in step (3) for 2 min using an arc current of 300 A, turning the sample over and repeating steps (3) and 4 for a total of 4 times, and rapidly cooling the sample in the furnace;

[0057] (5) The sample of step (4) was subjected to solution treatment at 1800°C in a high temperature furnace. -3 The treatment time under Pa vacuum condition is 6 hours, and the ingot is slowly cooled to room temperature with the furnace. The macroscopic morphology of the molybdenum-rhenium ingot after being taken out is as follows: Figure 3 As shown, coarse molybdenum-rhenium crystals with a size of several mm can be seen with the naked eye.

[0058] Example 2

[0059] This embodiment specifically includes the following steps:

[0060] (1) Take tungsten powder and rhenium powder with a purity of 99.99% and ball mill them under argon environment protection. The tungsten and rhenium elements in the alloy powder are evenly distributed. The EDS surface distribution diagram is as follows Figure 4 As shown, a W-3wt%Re alloy cold isostatic pressing sample was prepared, and then treated in a tube furnace for later use;

[0061] (2) Load the sample treated in step (1) into the copper alloy tooling mold of the arc melting equipment, close the furnace door, start the circulating cooling water, and wait until the equipment reaches 10 -2 Pa vacuum condition followed by gas washing;

[0062] (3) When the argon pressure reaches -0.02 MPa, the sample in step (2) is preheated for 100 s using an arc current of 180 A;

[0063] (4) arc melting the sample in step (3) for 5 min using an arc current of 350 A, turning the sample over and repeating steps (3) and 4 for a total of 6 times, and rapidly cooling the sample in the furnace;

[0064] (5) The sample of step (4) was subjected to solution treatment at 2200°C in a high temperature furnace. -3 The treatment time under the Pa vacuum condition was 9 hours, and the sample was slowly cooled to room temperature. After being taken out, the pure rhenium coarse crystal metallographic sample was prepared. After being corroded by a mixed solution of hydrogen peroxide and ammonia water, the SEM microstructure of the tungsten-rhenium alloy coarse crystal was as follows: Figure 5 As shown, the grain size can be larger than 1 mm.

[0065] Example 3

[0066] This embodiment specifically includes the following steps:

[0067] (1) taking 200 mesh rhenium powder with a purity of 99.99%, pressing it with a mold and then vacuum packaging it for later use;

[0068] (2) Load the sample treated in step (1) into the copper alloy tooling mold of the arc melting equipment, close the furnace door, start the circulating cooling water, the circulating water temperature is 25°C, and wait until the equipment reaches 10 -2 Pa vacuum condition followed by gas washing;

[0069] (3) When the argon pressure reaches -0.02 MPa, the sample in step (2) is preheated for 110 seconds using an arc current of 185 A;

[0070] (4) arc melting the sample in step (3) for 4 min using an arc current of 330 A, turning it over and repeating steps (3) and 4 for a total of 5 times, and rapidly cooling it in the furnace;

[0071] (5) The sample of step (4) was subjected to solution treatment at 2100°C in a high temperature furnace. -3 The treatment time under the Pa vacuum condition is 8 hours, and the sample is slowly cooled to room temperature with the furnace. After being taken out, the pure rhenium coarse crystal metallographic sample is prepared. After being corroded by a mixed solution of potassium ferrocyanide, potassium hydroxide and water, it can be observed that the grain size of the rhenium coarse crystal is mm level. The metallographic microstructure diagram is shown in the figure below. Figure 6 shown.

[0072] The above is a detailed introduction to a method for preparing coarse crystals of rhenium or rhenium alloy provided in the embodiment of the present application. The description of the above embodiment is only used to help understand the method and its core idea of ​​the present application; at the same time, for a person skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present application.

[0073] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. As mentioned throughout the specification and claims, "including" and "comprising" are open-ended terms, so they should be interpreted as "including / including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be determined by the definition of the attached claims.

[0074] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0075] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

Claims

1. A method for preparing coarse crystals of rhenium or rhenium alloy, characterized in that: The preparation method specifically comprises the following steps: S1) preparing an initial sample of rhenium or a rhenium alloy and performing a deoxidation treatment; S2) loading the initial sample of rhenium or rhenium alloy treated in S1) into the tooling mold of the arc melting equipment, closing the furnace door, turning on the circulating cooling water, and performing a gas washing treatment after the equipment reaches a vacuum condition; S3) preheating the initial sample of rhenium or rhenium alloy treated in S2), then arc melting it, turning it over and repeating the arc melting operation for multiple times to obtain a sample of rhenium or rhenium alloy; S4) subjecting the sample obtained in S3) to a solution treatment, and finally cooling the sample to room temperature in a furnace to obtain coarse crystals of rhenium or rhenium alloy.

2. The preparation method according to claim 1, characterized in that: The rhenium in S1) is pure rhenium, and the rhenium alloy is a rhenium alloy in which one or more main alloying elements of Mo, W, Ni, Zr, Hf, V, Cu, and K are added to rhenium, wherein the mass fraction of the rhenium element is 0.01% to 50%.

3. The preparation method according to claim 1, characterized in that: The initial sample in S1) is a sintered blank, a deformed block, a molded blank of a single substance powder or alloy powder, and a cold isostatically pressed blank; The deoxidation treatment includes removing the surface oxide scale, grinding and polishing, solution treatment and cleaning with acetone alcohol.

4. The preparation method according to claim 1, characterized in that: The tooling mold device in S2) is made of copper alloy material and has a water cooling device inside; The circulating cooling water is deionized water, and the temperature of the circulating cooling water is not higher than 30°C; The vacuum degree under the vacuum condition is not greater than 10 -2 Pa.

5. The preparation method according to claim 1, characterized in that: The preheating treatment in S3) is carried out in an argon environment with an argon pressure of -0.06 to -0.02 MPa; During the preheating process, the arc current used is 100-220A, and the preheating time is 1-2 minutes.

6. The preparation method according to claim 1, characterized in that: The arc melting process in S3) is carried out in an argon environment with an argon pressure of -0.06 to -0.02 MPa; the arc current used is 320 to 460 A, and each melting time is 2 to 6 minutes.

7. The preparation method according to claim 1, characterized in that: The solution treatment in S4) is carried out at 10 -3 It is carried out under vacuum conditions below Pa or under normal pressure hydrogen atmosphere; The solution treatment temperature is 1800-2300°C and the time is not less than 6 hours.

8. A coarse crystal of rhenium or rhenium alloy, characterized in that: The rhenium or rhenium alloy coarse crystals are prepared by the preparation method according to any one of claims 1 to 7.

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