Single crystal tungsten alloy material and preparation method thereof

Abstract

The invention relates to the technical field of powder metallurgy, in particular to a single crystal tungsten alloy material and a preparation method thereof, tungsten powder, single crystal tungsten powder, metal powder and mixed powder A are compounded, and the single crystal alloy material with high strength and toughness is prepared through mixing, cold isostatic pressing and spark plasma sintering. Wherein the mixed powder A is prepared from tungsten powder and metal powder through high-energy ball milling, so that mixed particles are fully refined, and the specific surface area and density are improved; the tungsten powder and the metal powder which are not subjected to ball milling can hinder excessive agglomeration caused by high-surface-energy particles obtained after ball milling, a uniform microstructure is obtained, and then the overall toughness of the alloy material is improved; and the single-crystal tungsten powder can be used as a strengthening phase to refine a grain structure, so that the expansion of cracks is effectively prevented, the toughness of the alloy material is further improved, and compared with the prior art, the alloy material has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of powder metallurgy, and in particular to a single crystal tungsten alloy material and a preparation method thereof. Background Art

[0002] Tungsten is a very important nonferrous metal. It has a series of characteristics such as high melting point, high density, low thermal expansion coefficient, and excellent corrosion resistance. It is usually used in vacuum filaments, welding electrodes, counterweight materials, shielding materials, military armor-piercing materials, and rocket nozzles. It has a wide range of applications in the electronics industry, engineering machinery, medical equipment, weapons and equipment, aerospace, and other fields.

[0003] In 1909, W.D. Coolidge of General Electric Company of the United States made tungsten billets by powder metallurgy, and then used mechanical processing to produce tungsten wires with ductility at room temperature, thus laying the foundation for the tungsten wire processing industry and the foundation for powder metallurgy. Tungsten alloy is an alloy composed of tungsten as the base and other elements. Among metals, tungsten has the highest melting point, high temperature hardness and creep resistance, as well as good thermal conductivity, electrical conductivity and electron emission properties, and a high specific gravity. In addition to being used in large quantities to manufacture hard alloys and as alloy additives, tungsten and its alloys are widely used in the electronics and electric light source industries, and are also used in the aerospace, casting, weapons and other departments to make rocket nozzles, die-casting molds, armor-piercing projectile cores, contacts, heating elements and heat shields.

[0004] When tungsten is exposed to air, it will be slightly oxidized at 400℃, and will be rapidly oxidized to WO3 at 500-600℃. WO3 will sublime significantly at above 800℃, so it is necessary to ensure vacuum environment or inert gas protection during the preparation of tungsten. The melting point of tungsten is 3410±20℃, which is the refractory metal with the highest melting point. Due to the high melting point, it is very difficult to prepare high-density tungsten and high-density tungsten alloys. The preparation methods of tungsten alloys include: consumable and non-consumable arc melting, electron beam melting, powder metallurgy, etc. Tungsten alloy is a high-density alloy and an important kinetic energy armor-piercing material. After reaching a certain exit speed, the tungsten-nickel-iron series of armor-piercing materials will be broken when the kinetic energy armor-piercing materials impact the armor, and effective armor-piercing cannot be achieved. Although the carat strength can be increased to more than 1300MPa by forging, the toughness of the material is poor and it is easy to break.

[0005] Most of the existing technical documents use powder metallurgy to prepare tungsten alloy materials. For example, patent CN115341112A discloses a high-strength ultrafine-grained tungsten-tantalum-nickel-iron-copper alloy and its preparation method and application. Tungsten-tantalum pre-alloy powder is prepared by mechanical alloying. The powder is further treated by hydrogen reduction to reduce the oxygen content, and low-melting-point nickel, iron and copper powder are added. The tungsten-tantalum-nickel-iron-copper alloy is obtained by cold isostatic pressing and sintering. The invention improves the sintering process and adopts a three-step sintering method. However, copper has a low melting point and a high saturated vapor pressure during sintering, and is easy to volatilize, which is not conducive to the compactness of the tungsten-tantalum-nickel-iron-copper alloy. A large number of pores are easily formed in the alloy structure. The toughness of the alloy material needs to be further improved.

[0006] Therefore, according to the above-mentioned related technologies, it is urgent to develop a single crystal tungsten alloy material and a preparation method thereof. Summary of the invention

[0007] In view of this, the purpose of the present invention is to provide a single crystal tungsten alloy material and a preparation method thereof, so as to solve the problem of poor toughness of tungsten alloy materials in the prior art.

[0008] Based on the above objectives, the present invention provides a single crystal tungsten alloy material and a preparation method thereof.

[0009] A single crystal tungsten alloy material is prepared from the following raw materials in parts by weight:

[0010] 0.5-1.3 parts of tungsten powder, 2.2-5 parts of single crystal tungsten powder, 0.1-0.3 parts of metal powder, 86-96 parts of mixed powder A;

[0011] The metal powder is obtained by mixing Ti, Nb, Ta, Ni, Mo, Y and K in a mass ratio of 1-3: 0.2-0.6: 3-5: 8-13: 0.1-0.3: 0.1-0.3: 0.3-0.7;

[0012] The mixed powder A is prepared by ball milling tungsten powder and metal powder.

[0013] Preferably, the preparation method of the single crystal tungsten powder is as follows:

[0014] Step A1. Dissolve ammonium metatungstate in deionized water and mix well to obtain an ammonium metatungstate solution;

[0015] Step A2. spray drying the ammonium metatungstate solution to obtain a spherical precursor powder;

[0016] Step A3: evenly spread the precursor powder in a boat, put it into a sintering furnace and perform reduction treatment with hydrogen to obtain single crystal tungsten powder.

[0017] Preferably, the mass ratio of ammonium metatungstate to deionized water in step A1 is 1:12-18;

[0018] During the spray drying process in step A2, the inlet air temperature is controlled at 150-220° C. and the feed rate is controlled at 280-450 mL / h.

[0019] Preferably, during the reduction treatment in step A3, the hydrogen flow rate is 500-750 mL / min, the temperature is 850-1100° C., and the insulation time is 1-3 h;

[0020] The thickness of the precursor powder in the boat is controlled to be 2-4 mm.

[0021] Preferably, the particle size of the tungsten powder is 5-8 μm, and the particle size of the metal powder is 2-30 μm.

[0022] Preferably, the preparation method of the mixed powder A is as follows:

[0023] The tungsten powder and the metal powder are mixed and subjected to high-energy ball milling to obtain mixed powder A;

[0024] The mass ratio of the tungsten powder to the metal powder is 82-88:6-11.

[0025] Preferably, the parameters of the high-energy ball milling are set as follows: the ball-to-material ratio is 5-7:1, the ball milling speed is 350-420 r / min, the ball milling time is 12-16 h, and the ball milling medium is obtained by mixing tungsten carbide balls with a diameter of 10 mm and tungsten carbide balls with a diameter of 5 mm in a mass ratio of 2-2.5:1.

[0026] A method for preparing a single crystal tungsten alloy material comprises the following steps:

[0027] Step S1. Mix the mixed powder A with tungsten powder, metal powder and single crystal tungsten powder, and press them into a compact using a cold isostatic pressing device to obtain a compact;

[0028] Step S2: In a hydrogen atmosphere, the compact is subjected to discharge plasma sintering twice to obtain a single crystal tungsten alloy material.

[0029] Preferably, the parameters of the cold isostatic pressing equipment in step S1 are set as follows: pressure is 210-240 MPa, and holding time is 150-210 s.

[0030] Preferably, the spark plasma sintering in step S2 includes a first spark plasma sintering and a second spark plasma sintering;

[0031] The parameters of the first discharge plasma sintering are as follows: sintering pressure is 10-25 MPa, temperature is 1300-1450° C., and holding time is 23-28 min;

[0032] The parameter settings of the second discharge plasma sintering are as follows: sintering pressure is 35-45 MPa, temperature is 1600-1850° C., and holding time is 2-5 min.

[0033] Beneficial effects of the present invention:

[0034] The present invention provides a single crystal tungsten alloy material and a preparation method thereof. The present invention prepares a single crystal alloy material with high strength and toughness by compounding tungsten powder, single crystal tungsten powder, metal powder and mixed powder A, mixing, cold isostatic pressing and discharge plasma sintering. The mixed powder A is prepared by high-energy ball milling of tungsten powder and metal powder, so that the mixed particles are fully refined, and the specific surface area and density are improved; the tungsten powder and metal powder that have not been ball milled can prevent excessive agglomeration caused by high surface energy particles obtained after ball milling, obtain a uniform microstructure, and then improve the overall toughness of the alloy material; the single crystal tungsten powder can be used as a strengthening phase to refine the grain structure and effectively prevent the expansion of cracks; the metal powder is obtained by mixing metals such as Ni, K, and Nb, and the toughness of the alloy material is further improved through the synergistic effect of multiple metals. Compared with the prior art, it has a wide range of application prospects. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0036] The sources and properties of some of the raw materials used in the present invention are as follows:

[0037] Ammonium metatungstate was purchased from Langfang Qianyao Chemical Reagent Co., Ltd.; tungsten powder was purchased from Ganzhou Huamao Tungsten Material Co., Ltd.; Ti was purchased from Baoji Jinshengda Titanium Co., Ltd.; Nb was purchased from Zhejiang Yamei Nanotechnology Co., Ltd.; Ta was purchased from Shanghai Liantian Materials Technology Co., Ltd.; Ni was purchased from Shanghai Xinyu Biotechnology Co., Ltd.; Mo was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; and Y was purchased from Beijing Xingrongyuan Company.

[0038] Embodiment 1: A method for preparing a single crystal tungsten alloy material, comprising the following steps:

[0039] S1. Dissolve 1g of ammonium metatungstate in 12g of deionized water and mix well to obtain an ammonium metatungstate solution;

[0040] S2. The ammonium metatungstate solution was spray dried, wherein the air inlet temperature was controlled at 150°C and the feed rate was controlled at 280 mL / h to obtain a spherical precursor powder;

[0041] S3. The precursor powder is evenly spread in a boat with a thickness of 2 mm, and placed in a sintering furnace for reduction treatment with hydrogen, wherein the hydrogen flow rate is 500 mL / min, the temperature is 850°C, and the holding time is 1 h to obtain a single crystal tungsten powder;

[0042] S4. 82 g of tungsten powder passing through a 2500 mesh sieve and 6 g of metal powder passing through a 6250 mesh sieve were mixed and subjected to high-energy ball milling to obtain mixed powder A. The ball milling parameters were set to a ball-to-material ratio of 5:1, a ball milling speed of 350 r / min, a ball milling time of 12 h, and a ball milling medium of a tungsten carbide ball with a diameter of 10 mm and a tungsten carbide ball with a diameter of 5 mm mixed in a mass ratio of 2:1;

[0043] S5. 86 g of mixed powder A was uniformly mixed with 0.5 g of tungsten powder, 0.1 g of metal powder and 2.2 g of single crystal tungsten powder, wherein the metal powder was mixed with 1 g of Ti, 0.2 g of Nb, 3 g of Ta, 8 g of Ni, 0.1 g of Mo, 0.1 g of Y and 0.3 g of K, and the pressure of the cold isostatic pressing equipment was set to 210 MPa, and the holding time was 210 s to obtain a compact;

[0044] S6. In a hydrogen atmosphere, the compact is subjected to two spark plasma sinterings. The parameters of the first spark plasma sintering are as follows: sintering pressure is 10 MPa, temperature is 1450°C, and holding time is 28 min. The parameters of the second spark plasma sintering are as follows: sintering pressure is 35 MPa, temperature is 1850°C, and holding time is 5 min. Thus, a single crystal tungsten alloy material is obtained.

[0045] Embodiment 2: A method for preparing a single crystal tungsten alloy material, comprising the following steps:

[0046] S1. Dissolve 1 g of ammonium metatungstate in 14 g of deionized water and mix well to obtain an ammonium metatungstate solution;

[0047] S2. The ammonium metatungstate solution was spray dried, wherein the air inlet temperature was controlled at 170°C and the feed rate was controlled at 320 mL / h to obtain a spherical precursor powder;

[0048] S3. The precursor powder was evenly spread in a boat with a thickness of 3 mm, and placed in a sintering furnace for reduction treatment with hydrogen, wherein the hydrogen flow rate was 550 mL / min, the temperature was 900 ° C, and the holding time was 1.5 h to obtain a single crystal tungsten powder;

[0049] S4. 84 g of tungsten powder passing through a 2500 mesh sieve and 7 g of metal powder passing through a 2000 mesh sieve were mixed and subjected to high-energy ball milling to obtain mixed powder A. The ball milling parameters were set to a ball-to-material ratio of 6:1, a ball milling speed of 370 r / min, a ball milling time of 13 h, and a ball milling medium of a tungsten carbide ball with a diameter of 10 mm and a tungsten carbide ball with a diameter of 5 mm in a mass ratio of 2:1;

[0050] S5. 89 g of mixed powder A was uniformly mixed with 0.8 g of tungsten powder, 0.2 g of metal powder and 3 g of single crystal tungsten powder, wherein the metal powder was mixed with 2 g of Ti, 0.2 g of Nb, 4 g of Ta, 9 g of Ni, 0.2 g of Mo, 0.2 g of Y and 0.4 g of K, and the pressure of the cold isostatic pressing equipment was set to 220 MPa, and the holding time was 190 s to obtain a compact;

[0051] S6. In a hydrogen atmosphere, the compact is subjected to two spark plasma sinterings. The parameters of the first spark plasma sintering are as follows: sintering pressure is 15 MPa, temperature is 1400°C, and holding time is 26 min. The parameters of the second spark plasma sintering are as follows: sintering pressure is 40 MPa, temperature is 1800°C, and holding time is 4 min. Thus, a single crystal tungsten alloy material is obtained.

[0052] Embodiment 3: A method for preparing a single crystal tungsten alloy material, comprising the following steps:

[0053] S1. Dissolve 1g of ammonium metatungstate in 16g of deionized water and mix well to obtain an ammonium metatungstate solution;

[0054] S2. The ammonium metatungstate solution was spray dried, wherein the air inlet temperature was controlled at 210°C and the feed rate was controlled at 380 mL / h to obtain a spherical precursor powder;

[0055] S3. The precursor powder is evenly spread in a boat with a thickness of 3 mm, and placed in a sintering furnace for reduction treatment with hydrogen, wherein the hydrogen flow rate is 620 mL / min, the temperature is 1000°C, and the holding time is 2 h to obtain a single crystal tungsten powder;

[0056] S4. 86 g of tungsten powder sieved through a 2000 mesh sieve and 8 g of metal powder sieved through an 800 mesh sieve were mixed and subjected to high-energy ball milling to obtain mixed powder A. The ball milling parameters were set to a ball-to-material ratio of 6:1, a ball milling speed of 390 r / min, a ball milling time of 14 h, and a ball milling medium of a tungsten carbide ball with a diameter of 10 mm and a tungsten carbide ball with a diameter of 5 mm at a mass ratio of 2.5:1;

[0057] S5. 92 g of mixed powder A was uniformly mixed with 1 g of tungsten powder, 0.2 g of metal powder and 4 g of single crystal tungsten powder, wherein the metal powder was mixed with 2.5 g of Ti, 0.5 g of Nb, 4.5 g of Ta, 11 g of Ni, 0.2 g of Mo, 0.2 g of Y and 0.6 g of K, and the pressure of the cold isostatic pressing equipment was set to 230 MPa, and the holding time was 170 s to obtain a compact;

[0058] S6. In a hydrogen atmosphere, the compact is subjected to two spark plasma sinterings. The parameters of the first spark plasma sintering are as follows: sintering pressure is 20 MPa, temperature is 1350°C, and holding time is 25 min. The parameters of the second spark plasma sintering are as follows: sintering pressure is 42 MPa, temperature is 1700°C, and holding time is 3 min. Thus, a single crystal tungsten alloy material is obtained.

[0059] Embodiment 4: A method for preparing a single crystal tungsten alloy material, comprising the following steps:

[0060] S1. Dissolve 1g of ammonium metatungstate in 18g of deionized water and mix well to obtain an ammonium metatungstate solution;

[0061] S2. The ammonium metatungstate solution was spray dried, wherein the air inlet temperature was controlled at 220°C and the feed rate was controlled at 450 mL / h to obtain a spherical precursor powder;

[0062] S3. The precursor powder was evenly spread in a boat with a thickness of 4 mm, and placed in a sintering furnace for reduction treatment with hydrogen, wherein the hydrogen flow rate was 750 mL / min, the temperature was 1100°C, and the holding time was 3 h to obtain a single crystal tungsten powder;

[0063] S4. 88 g of tungsten powder passing through a 2000 mesh sieve and 11 g of metal powder passing through a 625 mesh sieve were mixed and subjected to high-energy ball milling to obtain mixed powder A. The ball milling parameters were set to a ball-to-material ratio of 7:1, a ball milling speed of 420 r / min, a ball milling time of 16 h, and a ball milling medium of a tungsten carbide ball with a diameter of 10 mm and a tungsten carbide ball with a diameter of 5 mm at a mass ratio of 2.5:1;

[0064] S5. 96 g of mixed powder A was uniformly mixed with 1.3 g of tungsten powder, 0.3 g of metal powder and 5 g of single crystal tungsten powder, wherein the metal powder was mixed with 3 g of Ti, 0.6 g of Nb, 5 g of Ta, 13 g of Ni, 0.3 g of Mo, 0.3 g of Y and 0.7 g of K, and the pressure of the cold isostatic pressing equipment was set to 240 MPa, and the holding time was 150 s to obtain a compact;

[0065] S6. In a hydrogen atmosphere, the compact is subjected to two spark plasma sinterings. The parameters of the first spark plasma sintering are as follows: sintering pressure is 25 MPa, temperature is 1300°C, and holding time is 23 min. The parameters of the second spark plasma sintering are as follows: sintering pressure is 45 MPa, temperature is 1600°C, and holding time is 2 min. Thus, a single crystal tungsten alloy material is obtained.

[0066] Comparative Example 1:

[0067] Compared with Example 1, in this comparative example, single crystal tungsten powder is not added during the preparation process of the single crystal tungsten alloy material, and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a single crystal tungsten alloy material is obtained.

[0068] Comparative Example 2:

[0069] S1. Dissolve 1g of ammonium metatungstate in 12g of deionized water and mix well to obtain an ammonium metatungstate solution;

[0070] S2. The ammonium metatungstate solution was spray dried, wherein the air inlet temperature was controlled at 150°C and the feed rate was controlled at 280 mL / h to obtain a spherical precursor powder;

[0071] S3. The precursor powder is evenly spread in a boat with a thickness of 2 mm, and placed in a sintering furnace for reduction treatment with hydrogen, wherein the hydrogen flow rate is 500 mL / min, the temperature is 850°C, and the holding time is 1 h to obtain a single crystal tungsten powder;

[0072] S4. 82 g of tungsten powder passing through a 2500 mesh sieve and 6 g of metal powder passing through a 6250 mesh sieve were mixed and subjected to high-energy ball milling to obtain mixed powder A. The ball milling parameters were set to a ball-to-material ratio of 5:1, a ball milling speed of 350 r / min, a ball milling time of 12 h, and a ball milling medium of a tungsten carbide ball with a diameter of 10 mm and a tungsten carbide ball with a diameter of 5 mm mixed in a mass ratio of 2:1;

[0073] S5. 86 g of mixed powder A was uniformly mixed with 0.1 g of metal powder and 2.2 g of single crystal tungsten powder, wherein the metal powder was mixed with 1 g of Ti, 0.2 g of Nb, 3 g of Ta, 8 g of Ni, 0.1 g of Mo, 0.1 g of Y and 0.3 g of K, and the pressure of the cold isostatic pressing equipment was set to 210 MPa, and the holding time was 210 s to obtain a compact;

[0074] S6. In a hydrogen atmosphere, the compact is subjected to two spark plasma sinterings. The parameters of the first spark plasma sintering are as follows: sintering pressure is 10 MPa, temperature is 1450°C, and holding time is 28 min. The parameters of the second spark plasma sintering are as follows: sintering pressure is 35 MPa, temperature is 1850°C, and holding time is 5 min. Thus, a single crystal tungsten alloy material is obtained.

[0075] Comparative Example 3:

[0076] S1. Dissolve 1g of ammonium metatungstate in 12g of deionized water and mix well to obtain an ammonium metatungstate solution;

[0077] S2. The ammonium metatungstate solution was spray dried, wherein the air inlet temperature was controlled at 150°C and the feed rate was controlled at 280 mL / h to obtain a spherical precursor powder;

[0078] S3. The precursor powder is evenly spread in a boat with a thickness of 2 mm, and placed in a sintering furnace for reduction treatment with hydrogen, wherein the hydrogen flow rate is 500 mL / min, the temperature is 850°C, and the holding time is 1 h to obtain a single crystal tungsten powder;

[0079] S4. 82 g of tungsten powder passing through a 2500 mesh sieve and 6 g of metal powder passing through a 6250 mesh sieve were mixed and subjected to high-energy ball milling to obtain mixed powder A. The ball milling parameters were set to a ball-to-material ratio of 5:1, a ball milling speed of 350 r / min, a ball milling time of 12 h, and a ball milling medium of a tungsten carbide ball with a diameter of 10 mm and a tungsten carbide ball with a diameter of 5 mm mixed in a mass ratio of 2:1;

[0080] S5. 86 g of mixed powder A was uniformly mixed with 0.5 g of tungsten powder and 2.2 g of single crystal tungsten powder, wherein the metal powder was mixed with 1 g of Ti, 0.2 g of Nb, 3 g of Ta, 8 g of Ni, 0.1 g of Mo, 0.1 g of Y and 0.3 g of K, and the pressure of the cold isostatic pressing equipment was set to 210 MPa, and the holding time was 210 s to obtain a compact;

[0081] S6. In a hydrogen atmosphere, the compact is subjected to two spark plasma sinterings. The parameters of the first spark plasma sintering are as follows: sintering pressure is 10 MPa, temperature is 1450°C, and holding time is 28 min. The parameters of the second spark plasma sintering are as follows: sintering pressure is 35 MPa, temperature is 1850°C, and holding time is 5 min. Thus, a single crystal tungsten alloy material is obtained.

[0082] Comparative Example 4:

[0083] Compared with Example 1, this comparative example does not add mixed powder A during the preparation process of the single crystal tungsten alloy material, and the remaining steps and parameters are the same, which will not be repeated in this comparative example. Finally, a single crystal tungsten alloy material is obtained.

[0084] Comparative Example 5:

[0085] Compared with Example 1, this comparative example only replaces "2.2g single crystal tungsten powder" with "15g single crystal tungsten powder", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a single crystal tungsten alloy material is obtained.

[0086] Comparative Example 6:

[0087] Compared with Example 1, this comparative example only replaces "0.5g tungsten powder" with "5g tungsten powder", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a single crystal tungsten alloy material is obtained.

[0088] Comparative Example 7:

[0089] Compared with Example 1, this comparative example only replaces "0.1g metal powder" with "5g metal powder", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a single crystal tungsten alloy material is obtained.

[0090] Comparative Example 8:

[0091] S1. Dissolve 1g of ammonium metatungstate in 12g of deionized water and mix well to obtain an ammonium metatungstate solution;

[0092] S2. The ammonium metatungstate solution was spray dried, wherein the air inlet temperature was controlled at 150°C and the feed rate was controlled at 280 mL / h to obtain a spherical precursor powder;

[0093] S3. The precursor powder is evenly spread in a boat with a thickness of 2 mm, and placed in a sintering furnace for reduction treatment with hydrogen, wherein the hydrogen flow rate is 500 mL / min, the temperature is 850°C, and the holding time is 1 h to obtain a single crystal tungsten powder;

[0094] S4. 82 g of tungsten powder passing through a 2500 mesh sieve and 6 g of metal powder passing through a 6250 mesh sieve were mixed and subjected to high-energy ball milling to obtain mixed powder A. The ball milling parameters were set to a ball-to-material ratio of 5:1, a ball milling speed of 350 r / min, a ball milling time of 12 h, and a ball milling medium of a tungsten carbide ball with a diameter of 10 mm and a tungsten carbide ball with a diameter of 5 mm mixed in a mass ratio of 2:1;

[0095] S5. 86 g of mixed powder A was uniformly mixed with 0.5 g of tungsten powder, 0.1 g of metal powder and 2.2 g of single crystal tungsten powder, wherein the metal powder was mixed with 1 g of Ti, 0.2 g of Nb, 3 g of Ta, 8 g of Ni, 0.1 g of Mo, 0.1 g of Y and 0.3 g of K, and the pressure of the cold isostatic pressing equipment was set to 210 MPa, and the holding time was 210 s to obtain a compact;

[0096] S6. In a hydrogen atmosphere, the compact is subjected to spark plasma sintering, and the sintering parameters are set as follows: sintering pressure is 35 MPa, temperature is 1850°C, and holding time is 7 min, thereby obtaining a single crystal tungsten alloy material.

[0097] Comparative Example 9:

[0098] S1. Dissolve 1g of ammonium metatungstate in 12g of deionized water and mix well to obtain an ammonium metatungstate solution;

[0099] S2. The ammonium metatungstate solution was spray dried, wherein the air inlet temperature was controlled at 150°C and the feed rate was controlled at 280 mL / h to obtain a spherical precursor powder;

[0100] S3. The precursor powder is evenly spread in a boat with a thickness of 2 mm, and placed in a sintering furnace for reduction treatment with hydrogen, wherein the hydrogen flow rate is 500 mL / min, the temperature is 850°C, and the holding time is 1 h to obtain a single crystal tungsten powder;

[0101] S4. 82 g of tungsten powder passing through a 2500 mesh sieve and 6 g of metal powder passing through a 6250 mesh sieve were mixed and subjected to high-energy ball milling to obtain mixed powder A. The ball milling parameters were set to a ball-to-material ratio of 5:1, a ball milling speed of 600 r / min, a ball milling time of 12 h, and a ball milling medium of tungsten carbide balls with a diameter of 5 mm;

[0102] S5. 86 g of mixed powder A was uniformly mixed with 0.5 g of tungsten powder, 0.1 g of alloyed metal powder and 2.2 g of single crystal tungsten powder, wherein the alloyed metal powder was mixed with 1 g of Ti, 0.2 g of Nb, 3 g of Ta, 8 g of Ni, 0.1 g of Mo, 0.1 g of Y and 0.3 g of K, and the pressure of the cold isostatic pressing equipment was set to 210 MPa, and the holding time was 210 s to obtain a compact;

[0103] S6. In a hydrogen atmosphere, the compact is subjected to two spark plasma sinterings. The parameters of the first spark plasma sintering are as follows: sintering pressure is 10 MPa, temperature is 1450°C, and holding time is 28 min. The parameters of the second spark plasma sintering are as follows: sintering pressure is 35 MPa, temperature is 1850°C, and holding time is 5 min. Thus, a single crystal tungsten alloy material is obtained.

[0104] Performance Testing:

[0105] Tensile strength test:

[0106] Referring to the test standard GB / T228.1-2010 "Room Temperature Tensile Test of Metallic Materials Part 1: Test Method", the tensile strength of the single crystal tungsten alloy materials prepared in Examples 1-4 and Comparative Examples 1-8 were tested using a universal material testing machine;

[0107] Compressive strength:

[0108] Referring to the test standard GB / T228.1-2010 "Room Temperature Tensile Test of Metallic Materials Part 1: Test Method", the compressive strength of the single crystal tungsten alloy materials prepared in Examples 1-4 and Comparative Examples 1-8 were tested using a universal material testing machine;

[0109] Compressive strength calculation formula:

[0110] σ=P / A

[0111] Where σ is the compressive strength, P is the maximum load applied, and A is the cross-sectional area of ​​the single crystal tungsten alloy material;

[0112] Hardness test:

[0113] With reference to the test standard GB / T230.2-2002 “Surface Rockwell Hardness Test for Macroscopic Hardness Test of Metallic Materials”, the hardness of the single crystal tungsten alloy materials prepared in Examples 1-4 and Comparative Examples 1-8 was tested using a Rockwell hardness tester.

[0114] Table 1

[0115]

[0116]

[0117] Data Analysis:

[0118] It can be seen from Table 1 that the single crystal tungsten alloy material prepared by the present invention has better tensile strength, compressive strength and hardness. This may be because the present invention prepares the single crystal tungsten alloy material by compounding tungsten powder, single crystal tungsten powder, metal powder and mixed powder A in a specific proportion and controlling the parameter settings of mixing, cold isostatic pressing and spark plasma sintering. The mixed powder A is prepared by high-energy ball milling of tungsten powder and metal powder, which can fully refine the mixed particles, effectively hinder the movement of dislocations, and increase the specific surface area and density; the tungsten powder and metal powder that have not been ball milled can hinder the excessive agglomeration caused by high surface energy particles after ball milling, obtain a uniform microstructure, and be more uniform when subjected to pressure, thereby improving the overall toughness of the alloy material; single crystal tungsten powder can be used as a strengthening phase to refine the grain structure and effectively prevent the expansion of cracks; the metal powder is obtained by mixing metals such as Ni, K, and Nb, wherein Ni can be used as a sintering activator to promote the combination of various powders to obtain a dense and uniform microstructure; K will evaporate during the sintering process to form potassium bubbles, which play a pinning role on dislocations and grain boundaries in the alloy and inhibit the growth of grains; Nb can be infinitely dissolved with tungsten, thereby effectively improving the mechanical properties of the alloy such as hardness, and further improving the toughness of the alloy through the synergistic effect of multiple metal materials;

[0119] In Comparative Example 1, no single crystal tungsten powder is added, and in Comparative Example 5, "2.2 g single crystal tungsten powder" is replaced by "15 g single crystal tungsten powder". As can be seen from Table 1, the tensile strength, compressive strength and hardness of the two are worse than those of Example 1. This may be because the single crystal tungsten powder itself has high strength and toughness, which can effectively refine the grain structure and prevent the expansion of cracks. Even if the structure of part of the single crystal tungsten powder is destroyed during cold isostatic pressing, it can still introduce defects such as dislocations and grain boundaries to prevent the expansion of cracks, thereby improving the toughness of the alloy material. However, excessive single crystal tungsten powder will lead to uneven microstructure of the alloy material, thereby affecting its toughness and strength. In Comparative Example 2, no unmilled tungsten powder is added, and in Comparative Example 3, no unmilled metal powder is added. As can be seen from Table 1, the tensile strength, compressive strength and hardness of the two are worse than those of Example 1. The tensile strength, compressive strength and hardness are all worse than those in Example 1. This may be because the tungsten powder and metal powder that have not been ball-milled can prevent excessive agglomeration caused by high surface energy particles after ball milling, obtain a uniform microstructure, and be more uniform when subjected to pressure, thereby improving the overall toughness of the alloy material; Comparative Example 4 does not add mixed powder A. As can be seen from Table 1, its tensile strength, compressive strength and hardness are worse than those in Example 1. This may be because the mixed powder A is prepared by high-energy ball milling of tungsten powder and metal powder. This operation can make the mixed particles fully refined, effectively hinder the movement of dislocations, increase the specific surface area and density, and help improve the overall toughness of the alloy material; Comparative Example 6 replaces "0.5g tungsten powder" with "5g tungsten powder", and Comparative Example 7 replaces "0.1g metal powder" is replaced by "5g metal powder". It can be seen from Table 1 that the tensile strength, compressive strength and hardness of the two are worse than those of Example 1. This may be because adding a small amount of unmilled tungsten powder and metal powder to the alloy material can hinder the excessive agglomeration caused by high surface energy particles after ball milling, obtain a uniform microstructure, and be more uniform when subjected to pressure, thereby improving the overall toughness of the alloy material. However, adding too much unmilled tungsten powder and metal powder may destroy the particle size distribution of the original powder. Powders with different particle sizes and surface energies may cause uneven porosity, cracks and other microscopic defects, thereby reducing the overall toughness of the alloy material. Comparative Example 8 does not perform secondary plasma sintering. As can be seen from Table 1, its tensile strength, compressive strength and hardness are worse than those of Example 1. This may be because secondary sintering can further reduce holes and other defects. The density of the material is improved, the grains are refined, the number of grain boundaries is increased, and the toughness of the alloy material is enhanced; Comparative Example 9 changes the parameter settings of the high-energy ball mill, increases the rotation speed, and adjusts the "ball milling medium is obtained by mixing tungsten carbide balls with a diameter of 10 mm and tungsten carbide balls with a diameter of 5 mm in a mass ratio of 2:1" to "the ball milling medium is tungsten carbide balls with a diameter of 5 mm". As can be seen from Table 1, its tensile strength, compressive strength and hardness are worse than those of Example 1. This may be due to the smaller particle size of the obtained mixed powder A, but powders with too small particle size have higher surface energy and are easy to agglomerate. The pressure distribution is uneven during pressing and cracks are easy to occur. When the particle size of the mixed powder A is greatly different from that of the single crystal tungsten powder, the tungsten powder that has not been ball milled, and the metal powder, the filling will not be tight enough, the stress concentration phenomenon will be more obvious, and the toughness and strength of the alloy material will also decrease. .

[0120] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0121] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A single crystal tungsten alloy material, characterized in that: Prepared from the following raw materials by weight: 0.5-1.3 parts of tungsten powder, 2.2-5 parts of single crystal tungsten powder, 0.1-0.3 parts of metal powder, 86-96 parts of mixed powder A; The metal powder is obtained by mixing Ti, Nb, Ta, Ni, Mo, Y and K in a mass ratio of 1-3: 0.2-0.6: 3-5: 8-13: 0.1-0.3: 0.1-0.3: 0.3-0.7; The mixed powder A is prepared by ball milling tungsten powder and metal powder.

2. The single crystal tungsten alloy material according to claim 1, characterized in that: The preparation method of the single crystal tungsten powder is as follows: Step A1. Dissolve ammonium metatungstate in deionized water and mix well to obtain an ammonium metatungstate solution; Step A2. spray drying the ammonium metatungstate solution to obtain a spherical precursor powder; Step A3: evenly spread the precursor powder in a boat, put it into a sintering furnace and perform reduction treatment with hydrogen to obtain single crystal tungsten powder.

3. The single crystal tungsten alloy material according to claim 2, characterized in that: The mass ratio of ammonium metatungstate to deionized water in step A1 is 1:12-18; During the spray drying process in step A2, the inlet air temperature is controlled at 150-220° C. and the feed rate is controlled at 280-450 mL / h.

4. The single crystal tungsten alloy material according to claim 2, characterized in that: During the reduction treatment in step A3, the hydrogen flow rate is 500-750 mL / min, the temperature is 850-1100° C., and the insulation time is 1-3 h; The thickness of the precursor powder in the boat is controlled to be 2-4 mm.

5. The single crystal tungsten alloy material according to claim 1, characterized in that: The particle size of the tungsten powder is 5-8 μm, and the particle size of the metal powder is 2-30 μm.

6. The single crystal tungsten alloy material according to claim 1, characterized in that: The preparation method of the mixed powder A is as follows: The tungsten powder and the metal powder are mixed and subjected to high-energy ball milling to obtain mixed powder A; The mass ratio of the tungsten powder to the metal powder is 82-88:6-11.

7. The single crystal tungsten alloy material according to claim 6, characterized in that: The parameters of the high-energy ball mill are as follows: the ball-to-material ratio is 5-7:1, the ball mill speed is 350-420 r / min, the ball mill time is 12-16 h, and the ball mill medium is obtained by mixing tungsten carbide balls with a diameter of 10 mm and tungsten carbide balls with a diameter of 5 mm at a mass ratio of 2-2.5:

1.

8. A method for preparing a single crystal tungsten alloy material according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step S1. Mix the mixed powder A with tungsten powder, metal powder and single crystal tungsten powder, and press them into a compact using a cold isostatic pressing device to obtain a compact; Step S2: In a hydrogen atmosphere, the compact is subjected to spark plasma sintering to obtain a single crystal tungsten alloy material.

9. The method for preparing a single crystal tungsten alloy material according to claim 8, characterized in that: The parameters of the cold isostatic pressing equipment in step S1 are set as follows: pressure is 210-240 MPa, and holding time is 150-210 s.

10. The method for preparing a single crystal tungsten alloy material according to claim 8, characterized in that: The spark plasma sintering in step S2 includes a first spark plasma sintering and a second spark plasma sintering; The parameters of the first discharge plasma sintering are as follows: sintering pressure is 10-25 MPa, temperature is 1300-1450° C., and holding time is 23-28 min; The parameter settings of the second discharge plasma sintering are as follows: sintering pressure is 35-45 MPa, temperature is 1600-1850° C., and holding time is 2-5 min.

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