Sigma phase reinforced tungsten-rhenium alloy and preparation method thereof

Abstract

The invention discloses a Sigma phase reinforced tungsten-rhenium alloy and a preparation method thereof, and relates to the technical field of powder metallurgy and high-performance metal composite materials. The invention provides a Sigma phase reinforced tungsten-rhenium alloy. The Sigma phase reinforced tungsten-rhenium alloy comprises a tungsten-rhenium matrix and a Sigma phase, the mass percentage content of rhenium in the tungsten-rhenium matrix is greater than or equal to 20%; the compactness of the Sigma phase strengthened tungsten-rhenium alloy is larger than or equal to 96%, the hardness of the Sigma phase strengthened tungsten-rhenium alloy is larger than or equal to 560 HV, and the grain size is smaller than 15 micrometers. Meanwhile, the invention provides a preparation method of the high-performance Sigma phase strengthened tungsten-rhenium alloy, the traditional forging process is abandoned, the tungsten-rhenium alloy with high density and dispersed Sigma phase distribution is obtained through one-step forming, and the problem of forging fragmentation caused by the Sigma phase in the traditional forging process is solved.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy and high-performance metal composite materials, and in particular to a Sigama phase-reinforced tungsten-rhenium alloy and its preparation method. Background Technology

[0002] Tungsten (W), a refractory metal, plays an irreplaceable role in cutting-edge fields such as defense, aerospace, and nuclear industries due to its excellent properties, including high melting point, high density, high hardness, low sputtering rate, and low coefficient of thermal expansion. Specifically, its high-temperature and high-strength characteristics make it a core material for critical components such as jet engine nozzles; its excellent hardness and wear resistance make it the preferred material for friction stir welding heads and metal forming dies; and its low sputtering rate and low coefficient of thermal expansion make it the preferred material for the plasma-facing first wall in fusion reactors. However, pure tungsten materials suffer from fatal defects such as poor room-temperature ductility and toughness, and high-temperature recrystallization embrittlement, which severely limit its reliable application under extreme conditions.

[0003] To address the aforementioned technical bottlenecks, the materials science community generally employs alloying strategies, introducing rhenium (Re) to construct W-Re alloys. Studies have shown that the solid solution strengthening effect of Re can significantly improve the room-temperature plasticity and high-temperature strength of materials. However, solid solution strengthening alone has limited impact on the mechanical properties of tungsten alloys. Adding a second phase to the matrix can further enhance the mechanical properties of tungsten-rhenium alloys. Introducing second phases such as carbides and oxides into tungsten-rhenium alloys can effectively improve their mechanical properties; however, this introduction often brings new problems, such as uneven mixing causing second-phase agglomeration leading to forging fracture, carbides reacting with hydrogen during hydrogen sintering, and second-phase residues in the weld negatively affecting the base material.

[0004] In tungsten-rhenium alloys, when the rhenium content exceeds the solid solubility limit, a hard Sigma phase is formed. The presence of this phase adversely affects forging and processing, leading to material fracture. Furthermore, sintered billets are difficult to use directly due to their low density and hardness. Therefore, a new preparation technology is needed to produce high-performance Sigma-reinforced tungsten-rhenium alloys, improve their mechanical properties, and extend their service life under extreme environments. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to overcome the shortcomings of the prior art and provide a Sigama phase-strengthened tungsten-rhenium alloy with high density and high hardness and its preparation method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a Sigama phase-strengthened tungsten-rhenium alloy, comprising a tungsten-rhenium matrix and a Sigama phase; the mass percentage of rhenium in the tungsten-rhenium matrix is ​​≥20%; the density of the Sigama phase-strengthened tungsten-rhenium alloy is ≥96%; the hardness of the Sigama phase-strengthened tungsten-rhenium alloy is ≥560 HV; and the grain size is <15μm.

[0007] In one embodiment, the grain size is tested using the intercept method, which meets the national standard GB / T6394-2017 Method for Determination of Average Grain Size of Metals, and the calculation software is Image J.

[0008] In a second aspect, the present invention provides a method for preparing the Sigama phase-strengthened tungsten-rhenium alloy, comprising the following steps: (1) Ammonium metatungstate and ammonium rhenium are mixed evenly, spray-dried and then hydrogen-reduced to obtain powder 1; (2) Mix the powder 1 and rhenium powder evenly to obtain powder 2; (3) The powder 2 is hot-pressed and sintered to obtain the Sigama phase reinforced tungsten rhenium alloy.

[0009] This invention provides a method for preparing a high-performance sigama-phase strengthened tungsten-rhenium alloy, which avoids the forging fracture problem caused by the sigama phase in traditional forging processes. The high-performance sigama-phase strengthened tungsten-rhenium alloy is prepared by pressure-assisted sintering. The sigama phase is formed by the combination of incorporated rhenium and tungsten, while a large amount of rhenium is dissolved in the tungsten of the surrounding matrix, improving the toughness of the matrix. Ultimately, a high-performance alloy with a hard sigama phase / plastic tungsten-rhenium matrix is ​​obtained.

[0010] This invention employs hot-pressing sintering to prepare high-performance Sigama phase-reinforced tungsten-rhenium alloys. Through the coupling effect of temperature and stress fields, the densification process of the alloy is promoted. The invention focuses on breakthroughs in key technologies for the introduction of Sigama phase and the preparation of high-performance sintered blanks based on hot-pressing sintering, which is of great value for promoting the application of tungsten-rhenium materials in ultra-high temperature structural components, wear-resistant parts and other fields.

[0011] Preferably, in step (1), the specific parameters of the spray drying are: temperature 200-250℃, air inlet pressure 0.2-0.5MPa, atomization pressure 0.2-0.5MPa, feed rate 40-70rpm, solution mass concentration 20-40%, and the hydrogen reduction treatment process is 900-1100℃ for 4-6h.

[0012] Preferably, in step (1), the specific parameters of the spray drying are: temperature 230℃, air inlet pressure 0.3MPa, atomization pressure 0.3MPa, feed rate 50rpm, solution mass concentration 30%, and the hydrogen reduction treatment process is 1000℃ treatment for 5h.

[0013] Preferably, in step (1), the mass ratio of tungsten to rhenium in the ammonium metatungstate and ammonium rhenium is (3-4):1.

[0014] Preferably, in step (2), the rhenium powder has a Fisher particle size of 2-10 μm; and the rhenium powder has a mass percentage content of 3-8% in powder 2.

[0015] In one embodiment, the Fisher particle size of the rhenium powder is tested according to the requirements of the national standard GB / T 3249-2022, "Method for Determination of Fisher Particle Size of Metals and Their Compounds Powders".

[0016] The inventors discovered during actual experiments that the Fisher particle size of the rhenium powder affects the performance of the final Sigama phase-strengthened tungsten-rhenium alloy. If the Fisher particle size of the rhenium powder is too small, it is difficult to form the Sigama phase; if the Fisher particle size of the rhenium powder is too large, the Sigama phase will be too large, and there will be pure rhenium residue in the rhenium powder particles; thus, the density and hardness of the final Sigama phase-strengthened tungsten-rhenium alloy decrease.

[0017] During actual experiments, the inventors discovered that the mass percentage of rhenium powder in powder 2 affects the performance of the final Sigama-phase strengthened tungsten-rhenium alloy. When the mass percentage of rhenium powder in powder 2 is within the above-mentioned range, the final Sigama-phase strengthened tungsten-rhenium alloy exhibits better density and hardness.

[0018] Preferably, in step (2), the powder 1 and rhenium powder are mixed using a dual-motion mixing method, with the following mixing parameters: mixing time 4-12h and mixing speed 25-50rpm.

[0019] Preferably, in step (3), the hot pressing sintering temperature is 1800-2000℃, the hot pressing sintering time is 0.5-1h, and the hot pressing sintering pressure is 50-100Mpa.

[0020] In a third aspect, the present invention provides the application of the Sigama phase-strengthened tungsten-rhenium alloy in the fields of defense, aerospace and nuclear industry; specifically, the present invention provides the application of the Sigama phase-strengthened tungsten-rhenium alloy in armor-piercing projectile cores, missile engine nozzles, missile combustion chambers, missile tail fins and rocket nozzles.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for preparing a high-performance sigama-phase strengthened tungsten-rhenium alloy, which avoids the forging fracture problem caused by the sigama phase in traditional forging processes. The high-performance sigama-phase strengthened tungsten-rhenium alloy is prepared by pressure-assisted sintering. The sigama phase is formed by the combination of incorporated rhenium and tungsten, while a large amount of rhenium is dissolved in the tungsten of the surrounding matrix, improving the toughness of the matrix. Ultimately, a high-performance alloy with a hard sigama phase / plastic tungsten-rhenium matrix is ​​obtained.

[0022] This invention employs hot-pressing sintering to prepare high-performance Sigama phase-reinforced tungsten-rhenium alloys. Through the coupling effect of temperature and stress fields, the densification process of the alloy is promoted. The invention focuses on breakthroughs in key technologies for the introduction of Sigama phase and the preparation of high-performance sintered blanks based on hot-pressing sintering, which is of great value for promoting the application of tungsten-rhenium materials in ultra-high temperature structural components, wear-resistant parts and other fields. Attached Figure Description

[0023] Figure 1 Metallographic image of the tungsten-rhenium alloy prepared in Example 1; Figure 2 EDS image of the tungsten-rhenium alloy prepared in Example 1; Figure 3 Metallographic image of the tungsten-rhenium alloy prepared in Example 2; Figure 4 Metallographic image of the tungsten-rhenium alloy prepared in Example 3; Figure 5 The image shows the metallographic structure of the tungsten-rhenium alloy prepared in Example 4. Detailed Implementation

[0024] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The purpose is to provide a detailed understanding of the invention, not to limit it. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Unless otherwise specified, the experimental reagents and instruments designed in the embodiments and comparative examples of this invention are commonly used reagents and instruments, all of which are commercially available. Unless otherwise specified, the experimental methods used in the embodiments and comparative examples are conventional methods; and unless otherwise specified, the raw materials used in parallel experiments are from the same batch.

[0025] The raw materials of this invention will now be further described, but are not limited to the following raw materials: Ammonium metatungstate: 99.99% purity, Ganzhou Huamao Tungsten Materials Co., Ltd. Ammonium rhenium oxide: 99.99% purity, Jiangxi Copper Corporation Guixi Smelter; Rhenium Powder-1: Fisher particle size 2.3 microns, purity 99.99%, Jiangxi Copper Technology Research Institute Co., Ltd.; Rhenium Powder-2: Fisher particle size 9.1 microns, purity 99.99%, Jiangxi Copper Technology Research Institute Co., Ltd.; Rhenium Powder-3: Fisher particle size 1.8 microns, purity 99.99%, Jiangxi Copper Technology Research Institute Co., Ltd.; Rhenium Powder-4: Fischer particle size 13 microns, purity 99.99%, Jiangxi Copper Technology Research Institute Co., Ltd.; Examples and Comparative Examples Example 1 This invention provides a method for preparing a high-performance Sigama phase-strengthened tungsten-rhenium alloy, comprising the following steps: (1) Ammonium metatungstate and ammonium rhenium are mixed evenly, spray-dried and then hydrogen-reduced to obtain powder 1; the mass ratio of tungsten to rhenium in the ammonium metatungstate and ammonium rhenium is 3:1; the specific parameters of the spray drying are: temperature 230℃, inlet pressure 0.3MPa, atomization pressure 0.3MPa, feed rate 50rpm, solution mass concentration 30%; the hydrogen reduction treatment process is 1000℃ for 5h. (2) The powder 1 and rhenium powder are mixed evenly using a dual-motion mixer to obtain powder 2; the mixer parameters are: 4h, 50rpm, argon protection; The rhenium powder is rhenium powder-1; the mass percentage of the rhenium powder in powder 2 is 4%; (3) The powder 2 is hot-pressed and sintered to obtain the Sigama phase reinforced tungsten rhenium alloy; the hot-pressing and sintering temperature is 2000℃, the hot-pressing and sintering time is 1h, and the hot-pressing and sintering pressure is 100MPa.

[0026] Example 2 This invention provides a method for preparing a high-performance Sigama phase-strengthened tungsten-rhenium alloy. Compared with Example 1, only the rhenium powder used in step (2) is different, and rhenium powder-2 is selected.

[0027] Example 3 This invention provides a method for preparing a high-performance Sigama phase-strengthened tungsten-rhenium alloy. Compared with Example 1, only the rhenium powder used in step (2) is different, and rhenium powder-3 is selected.

[0028] Example 4 This invention provides a method for preparing a high-performance Sigama phase-strengthened tungsten-rhenium alloy. Compared with Example 1, only the rhenium powder used in step (2) is different, and rhenium powder-4 is selected.

[0029] Example 5 The invention provides a method for preparing a high-performance Sigama phase-strengthened tungsten-rhenium alloy. Compared with Example 1, the only difference is the mass percentage of rhenium powder-1 in powder 2 in step (2), where the mass percentage of rhenium powder-1 in powder 2 is 7%.

[0030] Example 6 The invention provides a method for preparing a high-performance Sigama phase-strengthened tungsten-rhenium alloy. Compared with Example 1, the only difference is the mass percentage of rhenium powder-1 in powder 2 in step (2), where the mass percentage of rhenium powder-1 in powder 2 is 1%.

[0031] Example 7 The invention provides a method for preparing a high-performance Sigama phase-strengthened tungsten-rhenium alloy. Compared with Example 1, the only difference is the mass percentage of rhenium powder-1 in powder 2 in step (2), where the mass percentage of rhenium powder-1 in powder 2 is 10%.

[0032] Example 8 This invention provides a method for preparing a high-performance Sigama phase-strengthened tungsten-rhenium alloy. Compared with Example 1, only the hot pressing sintering process in step (3) is different. The hot pressing sintering temperature is 1800℃, the hot pressing sintering time is 0.5h, and the hot pressing sintering pressure is 60MPa.

[0033] Example 9 This invention provides a method for preparing a high-performance Sigama phase reinforced tungsten-rhenium alloy. Compared with Example 1, only the hot pressing sintering process in step (3) is different. The hot pressing sintering temperature is 1600℃, the hot pressing sintering time is 1h, and the hot pressing sintering pressure is 100MPa.

[0034] Example 10 This invention provides a method for preparing a high-performance Sigama phase reinforced tungsten-rhenium alloy. Compared with Example 1, only the hot pressing sintering process in step (3) is different. The hot pressing sintering temperature is 2200℃, the hot pressing sintering time is 1h, and the hot pressing sintering pressure is 100MPa.

[0035] Example 11 This invention provides a method for preparing a high-performance Sigama phase reinforced tungsten-rhenium alloy. Compared with Example 1, only the hot pressing sintering process in step (3) is different. The hot pressing sintering temperature is 2000℃, the hot pressing sintering time is 1h, and the hot pressing sintering pressure is 60MPa.

[0036] Example 12 This invention provides a method for preparing a high-performance Sigama phase reinforced tungsten-rhenium alloy. Compared with Example 1, only the hot pressing sintering process in step (3) is different. The hot pressing sintering temperature is 2000℃, the hot pressing sintering time is 1h, and the hot pressing sintering pressure is 30MPa.

[0037] Example 13 This invention provides a method for preparing a high-performance Sigama phase-strengthened tungsten-rhenium alloy. Compared with Example 1, the mass ratio of tungsten to rhenium in ammonium metatungstate and ammonium rhenate is 4:1, the mixer parameters are: 12h, 25rpm, argon protection, and the remaining sintering parameters are the same.

[0038] Comparative Example 1 This invention provides a method for preparing a tungsten-rhenium alloy, which, compared with Example 1, omits step (2). The specific preparation method is as follows: (1) Ammonium metatungstate and ammonium rhenium are mixed evenly, spray-dried and then hydrogen-reduced to obtain powder 1; the mass ratio of tungsten to rhenium in the ammonium metatungstate and ammonium rhenium is 3:1; (3) The powder 1 is hot-pressed and sintered to obtain the tungsten-rhenium alloy; the hot-pressing and sintering temperature is 2000℃, the hot-pressing and sintering time is 1h, and the hot-pressing and sintering pressure is 100MPa.

[0039] Comparative Example 2 This invention provides a conventional method for preparing tungsten-rhenium alloy, the method comprising the following steps: (1) Tungsten powder and rhenium powder with a mass ratio of 3:1 were mixed and dispersed evenly by a dual-motion mixing process to obtain a uniformly mixed W-25Re powder. The mixing parameters were: 50 rpm, 4 h, and argon protection.

[0040] (2) The uniformly mixed W-25Re powder obtained in (1) is loaded into a rubber sleeve and then pressed in cold isostatic pressing to obtain W-25Re green body; (3) The W-25Re green blank obtained in (2) is sintered in a hydrogen sintering furnace to obtain W-25Re sintered blank. The sintering parameters are: 2300℃, holding time 8h. (4) The W-25Re sintered billet obtained in (3) is forged. The deformation amount in a single pass is 15%, and the total deformation amount is 70%, and finally the forged W-25Re bar is obtained.

[0041] Performance testing (1) Density: The density was measured by Archimedes method and the test method met the national standard GB / T 10421-2025 Determination of density of sintered metal friction materials. The density was measured by analytical balance and then divided by its theoretical density to obtain the density.

[0042] (2) Hardness: The hardness test results were obtained by micro Vickers hardness tester. Before the measurement, the equipment was calibrated by standard hardness block. Then, different points were randomly selected on the sample surface to test the hardness. There were at least 5 test points, and the distance between each two points was greater than 10 times the indentation area. The average value was taken.

[0043] (3) Wear volume: The friction test was carried out on a reciprocating friction device. The grinding ball was a Si3N4 ball, the reciprocating distance was 5mm, the reciprocating motion was 400 times per minute, the total time was 40min, and the load was 50N. After the friction was completed, the contour of the middle area of ​​the wear mark was obtained using a confocal microscope, and the contour width and depth were obtained through the contour curve to calculate the wear volume.

[0044] The test results are shown in Table 1.

[0045] Table 1 As shown in the table above, the Sigama phase-strengthened tungsten-rhenium alloy prepared by this invention has high density and hardness, and its wear volume is significantly lower than that of tungsten-rhenium alloys without Sigama phase strengthening and tungsten-rhenium alloys prepared by traditional rotary forging methods. Figure 1 The image shows the metallographic structure of the tungsten-rhenium alloy prepared in Example 1. Figure 2 The EDS image of the tungsten-rhenium alloy prepared in Example 1 shows that the prepared tungsten-rhenium alloy contains a large amount of Sigama phase. Figure 3 The image shows the metallographic structure of the tungsten-rhenium alloy prepared in Example 2. It can be seen that the prepared tungsten-rhenium alloy contains a large amount of Sigama phase. Figure 4 The image shows the metallographic structure of the tungsten-rhenium alloy prepared in Example 3. The tungsten-rhenium alloy does not contain the Sigama phase. Figure 5 The image shows the metallographic structure of the tungsten-rhenium alloy prepared in Example 4, which contains a large number of large-sized Sigama phases.

[0046] As can be seen from the comparison of Examples 1-4, when the Fisher particle size of the rhenium powder is 2-10 μm, the prepared Sigama phase-strengthened tungsten-rhenium alloy has high density and hardness, and low wear volume.

[0047] A comparison of Examples 1 and Examples 5-7 shows that when the rhenium powder has a mass percentage content of 3-8% in powder 2, the prepared Sigama phase-strengthened tungsten-rhenium alloy has high density and hardness, and low wear volume.

[0048] A comparison of Examples 1 and 8-12 shows that when the hot-pressing sintering temperature is 1800-2000℃, the hot-pressing sintering time is 0.5-1h, and the hot-pressing sintering pressure is 50-100MPa, the prepared Sigama phase-reinforced tungsten-rhenium alloy exhibits high density and hardness, and low wear volume. In Example 10, although the density is relatively high, the excessively high sintering temperature causes grain growth, resulting in lower hardness, poor wear resistance, and a large wear volume.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A sigama phase-strengthened tungsten-rhenium alloy, characterized in that, It includes a tungsten-rhenium matrix and a Sigama phase; the mass percentage of rhenium in the tungsten-rhenium matrix is ​​≥20%; the density of the Sigama phase-strengthened tungsten-rhenium alloy is ≥96%, the hardness of the Sigama phase-strengthened tungsten-rhenium alloy is ≥560HV, and the grain size is <15μm.

2. A method for preparing a Sigama phase-strengthened tungsten-rhenium alloy as described in claim 1, characterized in that, Includes the following steps: (1) Ammonium metatungstate and ammonium rhenium are mixed evenly, spray-dried and then hydrogen-reduced to obtain powder 1; (2) Mix the powder 1 and rhenium powder evenly to obtain powder 2; (3) The powder 2 is hot-pressed and sintered to obtain the Sigama phase reinforced tungsten rhenium alloy.

3. The method for preparing Sigama phase-strengthened tungsten-rhenium alloy as described in claim 2, characterized in that, In step (1), the mass ratio of tungsten to rhenium in ammonium metatungstate and ammonium rhenium is (3-4):

1.

4. The method for preparing Sigama phase-strengthened tungsten-rhenium alloy as described in claim 2, characterized in that, In step (2), the rhenium powder has a Fisher particle size of 2-10 μm; the rhenium powder has a mass percentage content of 3-8% in powder 2.

5. The method for preparing Sigama phase-strengthened tungsten-rhenium alloy as described in claim 2, characterized in that, In step (2), the powder 1 and rhenium powder are mixed using a dual-motion mixing method. The mixing parameters are: mixing time 4-12h, mixing speed 25-50rpm.

6. The method for preparing Sigama phase-strengthened tungsten-rhenium alloy as described in claim 2, characterized in that, In step (3), the hot pressing sintering temperature is 1800-2000℃, the hot pressing sintering time is 0.5-1h, and the hot pressing sintering pressure is 50-100Mpa.

7. The application of the Sigama phase-strengthened tungsten-rhenium alloy as described in claim 1 in the fields of national defense, aerospace and nuclear industry.

8. The application of the Sigama phase reinforced tungsten-rhenium alloy as described in claim 1 in armor-piercing projectile cores, missile engine nozzles, missile combustion chambers, missile tail fins, and rocket nozzles.

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