Preparation method of Sigma phase reinforced high-hardness wear-resistant tungsten-rhenium alloy bar

Abstract

The invention discloses a preparation method of a Sigma phase reinforced high-hardness wear-resistant tungsten-rhenium alloy bar. The method specifically comprises the following steps: carrying out ball milling on blue tungsten and ammonium rhenate to obtain uniformly mixed precursor powder; performing hydrogen reduction on the uniformly mixed precursor powder to obtain tungsten-rhenium pre-alloyed powder; pressing and sintering the tungsten-rhenium alloy powder to obtain a tungsten-rhenium alloy blank; the tungsten-rhenium alloy blank is subjected to free forging cogging treatment; heating and rotary swaging treatment; and performing high-temperature annealing treatment. By strictly controlling the rhenium content, the processing temperature and the annealing temperature in the alloy, a Sigama phase is separated out in the annealing process, the hardness of the tungsten-rhenium alloy is increased, and the wear resistance of the tungsten-rhenium alloy is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of powder metallurgy preparation, and in particular relates to a preparation method of a Sigma phase-reinforced high-hardness wear-resistant tungsten-rhenium alloy rod. Background Art

[0002] As the metal with the highest melting point, tungsten and its alloys are widely used in aviation, aerospace, navigation, electronic circuits, nuclear energy engineering, medical equipment, weapons and equipment, etc. due to its excellent hardness, density, thermal conductivity and low thermal expansion coefficient. China has abundant tungsten resources and has become the world's largest exporter of tungsten raw materials. However, there is still a significant gap between domestic tungsten deep-processing products and foreign countries. Export products are mainly sintered billets and powders. High-performance tungsten alloy deep-processing products still need to rely on imports.

[0003] Friction stir welding is a new solid phase welding technology invented by the British Welding Research Institute in 1991. It has the advantages of energy saving, environmental protection, high quality and high efficiency. Since its invention, it has received widespread attention. It is also the connection technology with the shortest time span from invention to industrial application in the history of world welding technology development. It is known as the "second revolution in welding history" after laser welding. Friction stir welding has been widely used in aviation, aerospace, shipbuilding, rail transportation, automobile and other industrial fields, and has now become the preferred welding process for high-strength aluminum alloys and magnesium alloys. In addition to aluminum and magnesium alloys, friction stir welding also has advantages in high melting point metals such as copper, steel, and titanium alloys, and has received more and more widespread attention. However, in the process of high melting point metal welding, the temperature of the friction stir head can reach 1000℃ due to the intense friction, which exceeds the recrystallization temperature of traditional iron-based materials. At such a high temperature, the strength of iron-based materials will drop rapidly, resulting in a rapid decrease in the service life of the material. Therefore, tungsten alloy has shown great potential in friction stir welding of high melting point metals due to its high recrystallization temperature.

[0004] Pure tungsten has high hardness and recrystallization temperature, but its own brittleness also limits its application in friction stir welding. Improving the composition of the alloy is one of the most effective ways to reduce the brittleness of tungsten. Adding solid solution elements to tungsten alloys or mixing insoluble second phases can improve the microstructure of tungsten alloys and thus improve the mechanical properties of the alloys. Adding solid solution elements to pure tungsten for alloying is one of the most commonly used methods to improve the mechanical properties of pure tungsten. In order to overcome the shortcomings of low toughness and low ductile-brittle transition temperature of pure tungsten, one or more elements that can dissolve in tungsten are added to tungsten to improve the mechanical properties of tungsten alloys, among which rhenium is the most common solid solution element. Since the first report in 1995 that the addition of rhenium can improve the toughness of tungsten, a large number of studies have been devoted to further exploring the mechanical properties of tungsten-rhenium alloys. As a material without a ductile-brittle transition temperature, the addition of rhenium to tungsten can also reduce the ductile-brittle transition temperature. In the tungsten-rhenium binary system, the solubility of rhenium in tungsten can reach 26% at room temperature. Within this solubility range, as the solid solution content of rhenium increases, its mechanical properties gradually improve.

[0005] The solid solution strengthening effect of rhenium in tungsten is limited by the solubility, and the introduction of a second phase into the tungsten-rhenium alloy can further improve the mechanical properties of the tungsten-rhenium alloy. In the tungsten-rhenium alloy, the maximum solubility of rhenium in tungsten at room temperature is 26%. When the rhenium content exceeds this limit, the Sigma phase will be generated. This phase is a hard and brittle phase. Although its appearance can increase the hardness of the tungsten alloy, it also reduces the machinability of the tungsten alloy. Therefore, during the forging deformation of the tungsten-rhenium alloy, the Sigma phase should be avoided. However, if the Sigma phase can be controlled not to appear in the tungsten-rhenium alloy during the processing, and the Sigma phase is formed after processing, the hardness of the tungsten-rhenium alloy can be improved while avoiding the decrease in machinability caused by the appearance of the Sigma phase. It should be noted that above 1500°C, the solubility of rhenium in tungsten exceeds 32%. By utilizing this characteristic, the precipitation of the Sigma phase can be avoided during the processing.

[0006] Traditional tungsten-rhenium alloys only have solid solution strengthening, low hardness and poor wear resistance, in response to the above problems. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method for preparing a tungsten-rhenium alloy rod with high hardness and wear resistance strengthened by Sigma phase in view of the above-mentioned deficiencies of the prior art. In the method, during the preparation process of the tungsten-rhenium alloy rod, the composition ratio, processing temperature and annealing temperature of the tungsten-rhenium alloy are strictly controlled to inhibit the formation of Sigma phase in the tungsten-rhenium alloy during the processing, and finally the tungsten-rhenium alloy rod is annealed to form Sigma phase, thereby obtaining a tungsten-rhenium alloy rod with high hardness and wear resistance strengthened by Sigma phase, which solves the problem of decreased processability caused by the formation of the second phase during forging.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a Sigma phase-reinforced high-hardness wear-resistant tungsten-rhenium alloy rod, the preparation method specifically comprising the following steps:

[0009] S1) preparing tungsten-rhenium alloy precursor powder;

[0010] S2) subjecting the tungsten-rhenium alloy precursor powder of S1) to hydrogen reduction treatment to obtain a tungsten-rhenium pre-alloyed powder;

[0011] S3) pressing the tungsten-rhenium pre-alloyed powder obtained in S2) by cold isostatic pressing, and sintering in a hydrogen furnace to obtain a tungsten-rhenium alloy billet;

[0012] S4) heating and forging the tungsten-rhenium alloy blank obtained in S3) using an air hammer to open the blank;

[0013] S5) using a rotary forging device to heat and rotary forge the tungsten-rhenium alloy blank treated in S4);

[0014] S6) using an annealing furnace to perform high temperature annealing treatment on the tungsten-rhenium alloy billet after the rotary forging treatment in S5), and finally obtaining a Sigma phase-reinforced high-hardness and wear-resistant tungsten-rhenium alloy rod.

[0015] Further, the specific steps in S1) are:

[0016] Blue tungsten and ammonium rhenate are used as raw materials, and blue tungsten and ammonium rhenate are weighed respectively according to the rhenium content accounting for 26% to 32% of the mass of tungsten and rhenium. The prepared powders are ball-milled by a ball mill to obtain a uniformly mixed tungsten-rhenium alloy precursor powder.

[0017] Furthermore, the mass purity of the blue tungsten and ammonium rhenate is above 99.99%; the Fisher particle sizes of the blue tungsten and ammonium rhenate are 1 μm to 20 μm and 1 μm to 70 μm, respectively.

[0018] Furthermore, the specific process of the hydrogen reduction treatment in S2) is: first, hydrogen reduction at a reduction temperature of 400°C to 600°C for 1h to 3h; then, hydrogen reduction at a reduction temperature of 900°C to 1100°C for 3h to 6h.

[0019] Furthermore, the density of the tungsten-rhenium alloy blank in S3) is between 88% and 93%, and the diameter of the blank should be a rod of φ40 mm to φ60 mm.

[0020] Furthermore, the heating equipment for the blank forging treatment in S4) is a hydrogen furnace, the heating temperature is 1650°C to 1800°C, the initial heating and holding time is 0.5h to 1h, the heating time between passes is 0.2h to 0.3h, the area reduction rate of the circular surface of the tungsten-rhenium alloy rod in each forging pass is 20% to 30%, and the diameter of the tungsten-rhenium alloy rod after air hammer forging is φ18mm to φ22mm.

[0021] Furthermore, the specific process of the rotary forging treatment in S5) is as follows: the heating temperature is 1550°C to 1600°C, the initial heating and holding time is 0.5h to 1h, the heating time between passes is 0.05h to 0.2h, the area reduction rate of the circular surface of the tungsten-rhenium alloy rod after each forging process is 15% to 25%, and the diameter of the tungsten-rhenium alloy rod after rotary forging is φ10mm to φ16mm.

[0022] Furthermore, the rotary forging treatment heating equipment in S5) is a hydrogen furnace, a vacuum furnace or an atmosphere furnace.

[0023] Furthermore, the annealing equipment in S6) is a hydrogen furnace, the annealing temperature is 1000° C. to 1300° C., and the time is 1 h to 10 h.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. The present invention sequentially prepares a precursor powder by mixing blue tungsten and ammonium rhenate by ball milling, obtains a pre-alloyed powder by hydrogen reduction, obtains a green body by cold isostatic pressing, obtains a tungsten-rhenium alloy billet by hydrogen furnace sintering, performs hot forging by air hammer, performs hot forging by rotary forging and performs high-temperature annealing to prepare a Sigma phase-reinforced high-hardness wear-resistant tungsten-rhenium alloy rod. In the preparation process, the powder composition, processing temperature and heat treatment temperature are strictly controlled, thereby obtaining a Sigma phase-reinforced high-hardness wear-resistant tungsten-rhenium alloy rod, which solves the problem that the traditional tungsten-rhenium alloy only relies on solid solution strengthening and has low hardness and poor wear resistance.

[0026] 2. Compared with the traditional process for preparing tungsten-rhenium alloy, the present invention creatively uses Sigma phase as the second strengthening phase to obtain a high-hardness and wear-resistant tungsten-rhenium alloy rod. The present invention utilizes the property that Sigma phase will be produced when rhenium exceeds the solid solubility limit in tungsten, controls the processing technology, avoids the precipitation of Sigma phase during the processing, and utilizes the advantage of high hardness of Sigma phase to obtain a tungsten-rhenium alloy strengthened with Sigma phase without reducing the processing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a process flow chart of a method for preparing a Sigma phase-reinforced high-hardness wear-resistant tungsten-rhenium alloy rod.

[0028] Figure 2 This is the XRD spectrum of the tungsten-rhenium pre-alloyed powder prepared in Example 1 of the present invention.

[0029] Figure 3 This is a metallographic microstructure diagram of the high hardness and wear-resistant tungsten-rhenium alloy rod prepared in Example 1 of the present invention.

[0030] Figure 4 Scanning electron microstructure and composition map of the high hardness and wear-resistant tungsten-rhenium alloy rod prepared in Example 1 of the present invention.

[0031] Figure 5 This is a friction three-dimensional morphology diagram of the high-hardness wear-resistant tungsten-rhenium alloy rod prepared in Example 1 of the present invention.

[0032] Figure 6 This is a real picture of the high hardness and wear-resistant tungsten-rhenium alloy rod prepared in Example 1 of the present invention.

[0033] Figure 7 This is a microstructure metallographic diagram of the high hardness and wear-resistant tungsten-rhenium alloy rod prepared in Example 2 of the present invention.

[0034] Figure 8 This is a three-dimensional friction morphology diagram of the high-hardness and wear-resistant tungsten-rhenium alloy rod prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments.

[0036] like Figure 1 As shown, the present invention provides a method for preparing a Sigma phase-reinforced high-hardness wear-resistant tungsten-rhenium alloy rod, the method comprising the following steps:

[0037] Step 1: blue tungsten and ammonium rhenate are prepared in proportion, and the prepared powder is ball-milled using a ball mill to obtain a uniformly mixed tungsten-rhenium alloy precursor powder;

[0038] Step 2: using a hydrogen reduction furnace to hydrogen reduce the tungsten-rhenium alloy precursor powder obtained in step 1 to obtain a tungsten-rhenium pre-alloy powder;

[0039] Step 3: Pressing the tungsten-rhenium mixed powder obtained in step 2 by cold isostatic pressing, and sintering it in a hydrogen furnace to obtain a tungsten-rhenium alloy billet;

[0040] Step 4: Using an air hammer to heat and forge the tungsten-rhenium alloy blank obtained in step 3;

[0041] Step 5, using rotary forging equipment to heat and rotary forge the tungsten-rhenium alloy blank that has been processed by the air hammer in step 4;

[0042] Step 6: Use an annealing furnace to perform high temperature annealing treatment on the tungsten-rhenium alloy blank after the rotary forging treatment in step 5, and finally obtain a high-hardness and wear-resistant tungsten-rhenium alloy.

[0043] In the above preparation method, the mass purity of the blue tungsten and ammonium rhenate in step 1 is above 99.99%; the Fisher particle sizes of the blue tungsten and ammonium rhenate are 1 μm to 20 μm and 1 μm to 70 μm, respectively. High purity can reduce the adverse effects of impurity elements on the processing properties of tungsten-rhenium alloy; fine raw material particles can promote uniform mixing of powders and improve the alloying degree of powders after hydrogen reduction.

[0044] In the above preparation method, the rhenium content in step 1 is between 26% and 32% of the mass of tungsten and rhenium. A high rhenium content is conducive to the formation of Sigma phase during the subsequent high-temperature annealing process. Usually, the rhenium content accounts for between 26% and 30%.

[0045] In the above preparation method, no single phase of rhenium appears in the tungsten-rhenium alloy powder after hydrogen reduction in step 2; the hydrogen reduction temperature system is 400°C to 600°C for 1h to 3h + 900°C to 1100°C for 3h to 6h. The selection of the above parameters is conducive to obtaining a powder with a higher degree of alloying and avoiding the formation of Sigma phase during sintering and processing.

[0046] In the above-mentioned preparation method, the density of the tungsten-rhenium alloy blank in step 3 is between 88% and 93%, and the diameter of the blank should be a rod of φ40mm to φ60mm.

[0047] In the above-mentioned preparation method, the heating equipment for the blanking forging treatment in step 4 is a hydrogen furnace, the heating temperature is 1650℃~1800℃, the initial heating and holding time is 0.5h~1h, the heating time between passes is 0.4h~0.6h, the area reduction rate of the circular surface of each forging process of the tungsten-rhenium alloy rod is 20%~30%, and the diameter of the tungsten-rhenium alloy rod after air hammer forging is φ18mm~φ22mm. The above-mentioned parameter selection is conducive to avoiding the precipitation of Sigma phase during the processing process to reduce the processability.

[0048] In the above-mentioned preparation method, the rotary forging heating equipment in step 5 is a hydrogen furnace, the heating temperature is 1550℃~1600℃, the initial heating holding time is 0.5h~1h, the heating time between passes is 0.3h~0.6h, the area reduction rate of the circular surface of the tungsten-rhenium alloy rod after each forging process is 15%~25%, and the diameter of the tungsten-rhenium alloy rod after rotary forging is φ10mm~φ16mm. The above-mentioned parameter selection is conducive to avoiding the precipitation of Sigma phase during the processing process to reduce the processability.

[0049] In the above-mentioned preparation method, the annealing equipment in step 6 can be a hydrogen furnace, a vacuum furnace and an atmosphere furnace, and the annealing temperature is 1000°C to 1300°C, and the time is 1h to 10h. At this temperature and time, the solubility of the Sigma phase can be reduced, the formation of the Sigma phase can be promoted, and the recrystallization of the tungsten-rhenium alloy can be avoided, and finally a tungsten-rhenium alloy rod with high hardness and high wear resistance can be obtained.

[0050] Example 1

[0051] like Figure 1 As shown, this embodiment includes the following steps:

[0052] Step 1: Prepare tungsten powder and rhenium powder with a mass purity of 99.99% and a Fisher particle size of 3 μm and 50 μm respectively according to a mass fraction of 73% and 27%, and use a ball mill to ball mill the prepared powder to obtain a uniformly mixed tungsten-rhenium alloy precursor powder;

[0053] Step 2: using a hydrogen reduction furnace to hydrogen reduce the tungsten-rhenium alloy precursor powder obtained in step 1 to obtain a tungsten-rhenium pre-alloy powder, wherein the hydrogen reduction parameters are 550° C. for 1 h and 1100° C. for 3 h;

[0054] Step 3: Press the tungsten-rhenium mixed powder obtained in step 2 by cold isostatic pressing, and sinter it in a hydrogen furnace to obtain a tungsten-rhenium alloy billet. The density of the sintered tungsten-rhenium alloy billet is 90%, and the billet diameter is φ50 mm.

[0055] Step 4: The tungsten-rhenium alloy billet obtained in step 3 is heated and forged by an air hammer, wherein the heating equipment for the forging is a hydrogen furnace, the heating temperature is 1700°C, the initial heating and holding time is 0.5h, the heating time between passes is 0.6h, the area reduction rate of the circular surface of the tungsten-rhenium alloy rod for each forging pass is 25%, and the diameter of the tungsten-rhenium alloy rod after the air hammer forging is φ18mm;

[0056] Step 5: Use rotary forging equipment to heat and rotary forge the tungsten-rhenium alloy billet after the air hammer blanking treatment in step 4. The rotary forging heating equipment is a hydrogen furnace, the heating temperature is 1600°C, the initial heating and holding time is 0.5h, the heating time between passes is 0.4h, and the area reduction rate of the circular surface of the tungsten-rhenium alloy rod after each forging process is 20%. The diameter of the tungsten-rhenium alloy rod after rotary forging is φ14mm;

[0057] Step six: Use an annealing furnace to perform high-temperature annealing treatment on the tungsten-rhenium alloy billet after the rotary forging treatment in step five. The annealing equipment is an atmosphere furnace, the annealing temperature is 1300°C, and the time is 5 hours, and finally a high-hardness and wear-resistant tungsten-rhenium alloy is obtained.

[0058] Figure 2 This is the XRD spectrum of the tungsten-rhenium pre-alloyed powder prepared in this example. It can be seen from the figure that no single rhenium phase appears after the powder is reduced with hydrogen, and the alloying degree of the powder is good.

[0059] Figure 3 The microstructure metallographic diagram of the high-hardness and wear-resistant tungsten-rhenium alloy rod prepared in this embodiment shows that Sigma phase is precipitated in the sample after annealing, which improves the hardness and wear resistance of the alloy.

[0060] Figure 4 From the scanning electron microscope and composition diagram of the microstructure of the high hardness and wear-resistant tungsten-rhenium alloy rod prepared in this embodiment, it can be seen that the rhenium content in the precipitate phase far exceeds the solid solubility limit of tungsten, and it can be determined that the Sigma phase has precipitated.

[0061] Table 1 shows the hardness and wear rate of the rods of this embodiment and conventional W-25Re. The friction test was conducted using a circular ball-disc friction high temperature tester. The friction test parameters were: temperature 1000°C, friction radius 3mm, rotation speed 560rpm, load 50N, and time 60min. It can be seen from the table that the hardness of the rods prepared in this embodiment is higher than that of the untreated W-25Re rods, and the wear resistance is also greatly improved.

[0062] Table 1 Hardness and wear rate of this embodiment and conventional W-25Re rod

[0063]

[0064] Example 2

[0065] like Figure 1 As shown, this embodiment includes the following steps:

[0066] Step 1: Prepare tungsten powder and rhenium powder with a mass purity of 99.99% and a Fisher particle size of 3 μm and 50 μm respectively according to a mass fraction of 70% and 30%, and use a ball mill to ball mill the prepared powder to obtain a uniformly mixed tungsten-rhenium alloy precursor powder;

[0067] Step 2: using a hydrogen reduction furnace to hydrogen reduce the tungsten-rhenium alloy precursor powder obtained in step 1 to obtain a tungsten-rhenium pre-alloy powder, wherein the hydrogen reduction parameters are 550° C. for 1 h and 1100° C. for 3 h;

[0068] Step 3: Press the tungsten-rhenium mixed powder obtained in step 2 by cold isostatic pressing, and sinter it in a hydrogen furnace to obtain a tungsten-rhenium alloy billet. The density of the sintered tungsten-rhenium alloy billet is 90%, and the billet diameter is φ50 mm.

[0069] Step 4: The tungsten-rhenium alloy billet obtained in step 3 is heated and forged by an air hammer, wherein the heating equipment for the forging is a hydrogen furnace, the heating temperature is 1700°C, the initial heating and holding time is 0.5h, the heating time between passes is 0.6h, the area reduction rate of the circular surface of the tungsten-rhenium alloy rod for each forging pass is 25%, and the diameter of the tungsten-rhenium alloy rod after the air hammer forging is φ18mm;

[0070] Step 5: Use rotary forging equipment to heat and rotary forge the tungsten-rhenium alloy billet after the air hammer blanking treatment in step 4. The rotary forging heating equipment is a hydrogen furnace, the heating temperature is 1600°C, the initial heating and holding time is 0.5h, the heating time between passes is 0.4h, and the area reduction rate of the circular surface of the tungsten-rhenium alloy rod after each forging process is 20%. The diameter of the tungsten-rhenium alloy rod after rotary forging is φ14mm;

[0071] Step six: Use an annealing furnace to perform high-temperature annealing treatment on the tungsten-rhenium alloy billet after the rotary forging treatment in step five. The annealing equipment is an atmosphere furnace, the annealing temperature is 1300°C, and the time is 5 hours, and finally a high-hardness and wear-resistant tungsten-rhenium alloy is obtained.

[0072] Figure 7 The microstructure metallographic diagram of the high-hardness and wear-resistant tungsten-rhenium alloy rod prepared in this embodiment shows that Sigma phase is precipitated in the sample after annealing, which improves the hardness and wear resistance of the alloy.

[0073] Table 2 shows the hardness and wear rate of the rods of this embodiment and conventional W-25Re. The friction test was conducted using a circular ball-disc friction high temperature tester. The friction test parameters were: temperature 1000°C, friction radius 3mm, rotation speed 560rpm, load 50N, and time 60min. It can be seen from the table that the hardness of the rods prepared in this embodiment is higher than that of the untreated W-25Re rods, and the wear resistance is also greatly improved.

[0074] Table 2 Hardness and wear rate of this embodiment and conventional W-25Re rod

[0075]

[0076] . The above is a detailed introduction to the preparation method of the Sigma phase reinforced high hardness wear-resistant tungsten-rhenium alloy rod 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 those of ordinary skill 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 a limitation on the present application.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present application, and should be within the scope of protection of the claims attached to the present application.

Claims

1. A method for preparing a Sigma phase-reinforced high-hardness wear-resistant tungsten-rhenium alloy rod, characterized in that: The preparation method specifically comprises the following steps: S1) preparing tungsten-rhenium alloy precursor powder; S2) performing hydrogen reduction treatment on the tungsten-rhenium alloy precursor powder obtained in S1) to obtain a tungsten-rhenium pre-alloyed powder; S3) pressing the tungsten-rhenium pre-alloyed powder obtained in S2) by cold isostatic pressing, and sintering it in a hydrogen furnace to obtain a tungsten-rhenium alloy billet; S4) heating and forging the tungsten-rhenium alloy blank obtained in S3) using an air hammer to open the blank; S5) using a rotary forging device to heat and rotary forge the tungsten-rhenium alloy blank treated in S4); S6) using an annealing furnace to perform high temperature annealing treatment on the tungsten-rhenium alloy billet after the rotary forging treatment in S5), and finally obtaining a Sigma phase-reinforced high-hardness and wear-resistant tungsten-rhenium alloy rod.

2. The preparation method according to claim 1, characterized in that: The specific steps in S1) are: Blue tungsten and ammonium rhenate are taken as raw materials, and the blue tungsten and ammonium rhenate are weighed respectively according to the rhenium content accounting for 26% to 32% of the mass of tungsten and rhenium. After mixing, they are ball-milled by using a ball mill to obtain a uniformly mixed tungsten-rhenium alloy precursor powder.

3. The preparation method according to claim 2, characterized in that: The mass purity of the blue tungsten and ammonium rhenate is above 99.99%; The Fischer-Strauss particle sizes of the blue tungsten and ammonium rhenate are 1 μm to 20 μm and 1 μm to 70 μm respectively.

4. The preparation method according to claim 1, characterized in that: The specific process of the hydrogen reduction treatment in S2) is: first, hydrogen reduction at a reduction temperature of 400°C to 600°C for 1h to 3h; then, hydrogen reduction at a reduction temperature of 900°C to 1100°C for 3h to 6h.

5. The preparation method according to claim 1, characterized in that: The density of the tungsten-rhenium alloy blank in S3) is between 88% and 93%, and the diameter of the blank should be a rod of φ40mm to φ60mm.

6. The preparation method according to claim 1, characterized in that: The heating equipment for the blank forging treatment in S4) is a hydrogen furnace, the heating temperature is 1650°C to 1800°C, the initial heating and holding time is 0.5h to 1h, the heating time between passes is 0.2h to 0.3h, the area reduction rate of the circular surface of the tungsten-rhenium alloy rod in each forging process is 20% to 30%, and the diameter of the tungsten-rhenium alloy rod after air hammer forging is φ18mm to φ22mm.

7. The preparation method according to claim 1, characterized in that: The specific process of the rotary forging treatment in S5) is as follows: the heating temperature is 1550°C to 1600°C, the initial heating and holding time is 0.5h to 1h, the heating time between passes is 0.05h to 0.2h, the area reduction rate of the circular surface of the tungsten-rhenium alloy rod after each forging process is 15% to 25%, and the diameter of the tungsten-rhenium alloy rod after rotary forging is φ10mm to φ16mm.

8. The preparation method according to claim 1, characterized in that: The rotary forging heating equipment in S5) is a hydrogen furnace, a vacuum furnace or an atmosphere furnace.

9. The preparation method according to claim 1, characterized in that: The annealing equipment in S6) is a hydrogen furnace, the annealing temperature is 1000° C. to 1300° C., and the time is 1 h to 10 h.

10. A tungsten-rhenium alloy rod, characterized in that: The tungsten-rhenium alloy rod is prepared by the preparation method according to any one of claims 1 to 9.

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