Tungsten-copper composite material molded part and preparation method thereof

Abstract

The invention relates to a tungsten-copper composite material forming part and a preparation method thereof, and belongs to the technical field of metal composite materials. The raw materials of the forming part are composed of a tungsten source, a copper source and a forming agent. The tungsten source consists of modified tungsten powder and tungsten powder; the modified tungsten powder is obtained by adding a reinforcing phase and an activating element, wetting and adhesion of a tungsten phase and a copper phase can be promoted, the sintering performance of the formed part is improved, and the comprehensive performance of the formed part is improved; the forming agent is added to ensure that the powder has good flowability and formability, the problems that a large-size tungsten-copper blank is poor in compression molding formability and high in manufacturing cost are solved, and a tungsten-copper composite material formed part which is uniform in structural component, low in cost and easy to form is obtained. The preparation method comprises the following steps: dispersing an activating element and a reinforcing phase into tungsten powder through a ball milling method to obtain modified tungsten powder, adding double-granularity composite powder of the modified tungsten powder and unmodified tungsten powder into a forming agent to obtain easily-formed composite powder, and pressing the composite powder into a large-size tungsten copper green body, the method has the characteristics of low cost, good repeatability, controllable process, raw material saving and the like.

Description

Technical Field

[0001] This invention relates to a tungsten-copper composite material molded part and its preparation method, belonging to the field of metal composite material technology. Background Technology

[0002] Tungsten-copper composites are pseudo-alloys composed of refractory tungsten, which neither dissolves in solids nor forms intermetallic compounds, and highly conductive copper. These composites possess both the excellent electrical and thermal conductivity of copper and the high strength, high melting point, arc erosion resistance, and low coefficient of thermal expansion of tungsten, making them widely used in electrical contacts, electronic packaging, heat sink materials, electrode materials, and machinery.

[0003] Due to the immiscibility, significant difference in melting points, and poor wettability between tungsten and copper in tungsten-copper composites, the sintering performance of these composites is affected, resulting in uneven microstructure distribution and poor physical and mechanical properties. Furthermore, the large density difference between tungsten and copper powders can easily lead to uneven density distribution during molding due to gravity, causing defects such as cracks and missing corners during compression molding. When preparing complex-shaped, large-diameter (90mm ~ 150mm) or thick (15mm ~ 30mm) tungsten-copper composite parts, isostatic pressing followed by shaping and cutting is typically used. This process inevitably leads to raw material waste, resulting in low raw material utilization and high costs.

[0004] With the continuous rise in raw material prices, higher demands are being placed on controlling the production costs of tungsten-copper composite molded parts. Simultaneously, as customers increasingly demand higher product performance, the production of high-performance tungsten-copper composite molded parts has become an inevitable trend. Therefore, a technical solution that can address the aforementioned shortcomings is urgently needed. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, one of the objectives of this invention is to provide a tungsten-copper composite material molded part. The molded part is modified by adding reinforcing phases and activating elements to obtain modified tungsten powder, which can promote the wetting and adhesion of the tungsten phase and the copper phase, improve its sintering performance, and enhance material properties. The addition of molding agents ensures that the powder has good flowability and formability, solving the problems of poor molding properties and high manufacturing costs of large-size tungsten-copper blanks. This results in a tungsten-copper composite material molded part with uniform microstructure, low cost, and easy molding. The second objective of this invention is to provide a method for preparing tungsten-copper composite molded parts. The method involves dispersing activating elements and reinforcing phases into tungsten powder using a mechanical alloying method to obtain modified tungsten powder. Then, a molding agent is added to the modified tungsten powder and unmodified tungsten powder in a dual-particle-size composite powder to obtain an easily formable composite powder. The composite powder can be pressed into large-sized tungsten-copper green blanks. Compared with cold isostatic pressing combined with shaping, this method has the advantages of low cost, good repeatability, process control, and saving raw materials.

[0006] To achieve the objectives of this invention, the following technical solutions are provided.

[0007] A tungsten-copper composite material molded part, wherein the raw materials of the molded part consist of a tungsten source, a copper source, and a molding agent; based on the total mass of tungsten and copper in the molded part being 100%, the mass fraction of tungsten is 50% to 93%, and the mass fraction of copper is 7% to 50%; the amount of molding agent used is 0.5% to 6% of the total mass of the tungsten source and the copper source; further, the mass fraction of tungsten is 60% to 90%, and the mass fraction of copper is 10% to 40%; the amount of molding agent used is 1.5% to 4% of the total mass of the tungsten source and the copper source.

[0008] The tungsten source is composed of modified tungsten powder and tungsten powder. Based on the mass of the tungsten source being 100%, the mass fraction of modified tungsten powder is 50% to 80%, and the mass fraction of tungsten powder is 20% to 50%.

[0009] When the mass fraction of tungsten in the molded part is 85% or more and the mass fraction of copper is 15% or less, and further, when the mass fraction of tungsten is 90% and the mass fraction of copper is 10%, the copper source is a copper block, and the amount of copper block used is 1.2 times the copper content in the molded part. When the mass fraction of tungsten in the molded part is less than 85% and the mass fraction of copper is more than 15%, and further, when the mass fraction of tungsten is 60% to 80% and the mass fraction of copper is 20% to 40%, the copper source is composed of copper powder and copper blocks; the ratio of the copper mass fraction derived from copper powder to copper blocks is 1:4 to 4:1, and further, the ratio is 2:3 to 7:3. When the copper source is copper blocks, the amount of copper blocks used is 1.2 times its corresponding copper content. When the mass fraction of tungsten in the molded part is 85% and the mass fraction of copper is 15%, the copper source is copper block, or copper powder and copper block.

[0010] The molding agent is at least one of paraffin wax, phenolic resin, polyvinyl alcohol, and nitrile rubber.

[0011] Taking the total mass of the modified tungsten powder raw material as 100%, the individual components and their mass fractions are as follows: Activating elements: 0.35% ~ 2% Tungsten carbide 0.2% ~ 2%, Graphene oxide 0.01% ~ 0.1%, Tungsten powder balance; Furthermore, taking the total mass of the modified tungsten powder raw material as 100%, the individual components and their mass fractions are as follows: Activating elements: 0.7% ~ 1.5% Tungsten carbide 0.25% ~ 1.5%, Graphene oxide 0.02% ~ 0.08%, Tungsten powder balance; The activating element is at least one of iron powder, nickel powder, and cobalt powder; further, the activating element is nickel powder.

[0012] Tungsten carbide powder and graphene oxide are used as reinforcing phases.

[0013] Further, the molded part is a large-sized molded part with a diameter of 90 mm to 150 mm or a thickness of 15 mm to 30 mm; even further, the molded part is a large-sized molded part with a diameter of 95 mm to 150 mm or a thickness of 22 mm to 24 mm.

[0014] A method for preparing a tungsten-copper composite material molded part according to the present invention, the method comprising the following steps: (1) Tungsten powder, activating elements, tungsten carbide powder and graphene oxide dispersion are mixed, then mixed evenly by wet ball milling, then separated and dried to obtain modified tungsten powder; (2) When the copper source is a copper block, the modified tungsten powder and tungsten powder obtained in step (1) are mixed to obtain metal powder, which is added to the molding agent solution, stirred and mixed evenly, and then dried and sieved to obtain composite powder; When the copper source is composed of copper powder and copper block, the modified tungsten powder, tungsten powder and copper powder obtained in step (1) are mixed to obtain metal powder, which is added to the molding agent solution, stirred and mixed evenly, and then dried and sieved to obtain composite powder; (3) The composite powder prepared in step (2) is loaded into a pressing mold for molding to obtain a composite material green body; (4) The composite material green blank prepared in step (3) is placed into a sintering and melting container, a copper block is placed in it, and hydrogen gas is passed through for sintering and melting to obtain a tungsten copper composite material molded part.

[0015] Furthermore, in step (1): The graphene oxide dispersion was obtained by dissolving and dispersing graphene oxide in anhydrous ethanol; The wet ball milling process uses cemented carbide grinding balls with a ball-to-material mass ratio of 5:1 to 50:1. The grinding media is anhydrous ethanol, which accounts for 40% to 80% of the grinding jar volume. The milling speed is 100 r / min to 500 r / min, and the milling time is 5 h to 48 h. Alternatively, the ball-to-material mass ratio is 20:1 to 45:1, the grinding media is anhydrous ethanol, which accounts for 40% to 60% of the grinding jar volume, the milling speed is 200 r / min to 400 r / min, and the milling time is 20 h to 48 h. The drying method is vacuum drying, with a drying temperature of 50 ℃ ~ 80 ℃ and a drying time of 4 h ~ 24 h; further, the drying temperature is 50 ℃ ~ 75 ℃ and the drying time is 6 h ~ 20 h.

[0016] In step (2): The molding agent solution is prepared by using a suitable solvent in the prior art. For example, paraffin wax is dissolved in gasoline to obtain a paraffin wax solution, phenolic resin is dissolved in anhydrous ethanol to obtain a phenolic resin solution, polyvinyl alcohol is dissolved in anhydrous ethanol to obtain a polyvinyl alcohol solution, and nitrile rubber is liquid nitrile rubber.

[0017] During mixing, the stirring rate is 20 r / min ~ 200 r / min, and the stirring time is 20 min ~ 4 h; further, the stirring rate is 50 r / min ~ 150 r / min, and the stirring time is 1 h ~ 3 h. The drying method is vacuum drying, with a drying temperature of 50 ℃ ~ 80 ℃ and a drying time of 4 h ~ 24 h. Alternatively, the drying temperature is 60 ℃ ~ 80 ℃ and the drying time is 4 h ~ 8 h.

[0018] In step (4): The specific conditions for sintering and melting are as follows: heat to 700℃~900℃ at a heating rate of 10℃ / min~35℃ / min, hold for 30 min~60 min; then heat to 1000℃~1100℃ at a heating rate of 10℃ / min~35℃ / min, hold for 30 min~60 min; finally heat to 1200℃~1450℃ at a heating rate of 10℃ / min~35℃ / min, hold for 30 min~120 min. Furthermore, the specific conditions for sintering and melting are as follows: heating to 700℃~900℃ at a heating rate of 15℃ / min~35℃ / min, holding for 30 min~60 min; then heating to 1000℃~1100℃ at a heating rate of 15℃ / min~25℃ / min, holding for 30 min~40 min; finally heating to 1300℃~1450℃ at a heating rate of 20℃ / min~25℃ / min, holding for 60 min~120 min; A tungsten-copper composite material molded part is obtained; the molded part can be removed after cooling in the furnace.

[0019] Beneficial effects (1) The present invention provides a tungsten-copper composite material molded part. The molded part achieves the synergistic effect of multiple components such as reinforcing phase, activating element, composite tungsten powder with different ratios and molding agent through system design. It solves the key technical problems of uneven copper phase distribution, poor interface wettability, high porosity, and high molding process cost of large diameter (90mm ~ 150mm) or thick (15mm ~ 30mm) profiles in the existing tungsten-copper composite materials. The structure of the molded part is more uniform, the tungsten-copper interface strength is improved, and the comprehensive performance is greatly improved. (2) The present invention provides a tungsten-copper composite material molded part, wherein the raw material of the molded part is modified tungsten powder by adding reinforcing phase and activating element, which can promote the wetting and adhesion of tungsten phase and copper phase, improve its sintering performance, and improve the overall performance of the molded part. (3) The present invention provides a tungsten copper composite material molded part. The raw material of the molded part uses two composite powders, modified tungsten powder and unmodified tungsten powder, as the pressing powder raw material for tungsten copper blank. By utilizing the filling effect and adhesion effect between the two powder particles, the density of the molded part is greatly improved. (4) The present invention provides a tungsten copper composite molded part, wherein a molding agent is added to the raw material of the molded part, so that a strong intermolecular force is formed between the surfaces of the metal powder, ensuring the tight bonding of particles or blanks during the molding process, and greatly improving the strength and formability of large-size tungsten copper blanks; (5) The present invention provides a method for preparing tungsten copper composite material molded parts. The method disperses the activating elements and reinforcing phase into tungsten powder by mechanical alloying. In the subsequent sintering and infiltration, it promotes the wetting and adhesion of the copper phase and the tungsten phase, accelerates the diffusion of atoms, and reduces the sintering temperature. At the same time, after undergoing plastic deformation, hardening and crushing, and repeated cold welding and crushing processes, the tungsten powder changes from a spherical shape to an irregular structure and the particle size is also smaller. Compared with the spherical powder structure, the irregular powder structure can weaken the interfacial stress between powders to a certain extent, and can also make the powder more compacted, reduce porosity, and ultimately help to enhance the density and mechanical properties of the composite material. (6) The present invention provides a method for preparing tungsten copper composite material molded parts. The method can press into large-diameter (90 mm ~ 150 mm) or thick (15 mm ~ 30 mm) tungsten copper blanks. Compared with the method of cold isostatic pressing combined with shaping, it has the characteristics of low cost, good repeatability, process controllability and saving raw materials. It can prepare a tungsten copper composite material molded part with uniform structure and composition, low cost and easy molding. Attached Figure Description

[0020] Figure 1 A photograph of the tungsten-copper composite ring-shaped part prepared in Example 1; Figure 2 The image shows a scanning electron microscope (SEM) image of the fracture surface of the tungsten-copper composite ring prepared in Example 1. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the present invention.

[0022] In the following embodiments: Paraffin solution is prepared by dissolving paraffin in gasoline at 90°C. The phenolic resin solution is prepared by dissolving phenolic resin in anhydrous ethanol at 25 °C. Polyvinyl alcohol solution is prepared by dissolving polyvinyl alcohol in anhydrous ethanol at 80 °C; The prepared tungsten-copper composite molded parts were observed and their performance was tested as follows: (1) Observation by scanning electron microscope (SEM) The tungsten-copper composite ring was observed using a scanning electron microscope (KYKY-EM6900M) manufactured by Beijing Zhongke Keyi Technology Development Co., Ltd. (2) Performance testing Density was measured using a density analysis balance; The hardness tester used was a Brinell hardness tester. Conductivity was measured using a digital eddy current metal conductivity meter.

[0023] Example 1 A tungsten-copper composite material molded part, wherein the molding agent is composed of a tungsten source, a copper source, and a molding agent, wherein, based on the total mass of tungsten and copper in the molded part being 100%, the mass fraction of tungsten is 75% and the mass fraction of copper is 25%; the molding agent is phenolic resin, and its dosage is 3% of the total mass of the tungsten and copper sources. The tungsten source is composed of modified tungsten powder and tungsten powder in a mass ratio of 2:1; Of the copper in the molded part, 10% by mass of the copper comes from copper powder of equal mass, and 15% by mass of the copper comes from copper blocks of 1.2 times the mass.

[0024] Taking the total mass of the modified tungsten powder raw material as 100%, the individual components and their mass fractions are as follows: Activating element 0.7%, Tungsten carbide 0.25%, Graphene oxide 0.02%, Tungsten powder 99.03%; The activating element is nickel powder; Tungsten carbide powder and graphene oxide are used as reinforcing phases.

[0025] The molded part is a ring-shaped part of tungsten-copper composite material with an outer diameter of 150 mm, an inner diameter of 60 mm, and a thickness of 6 mm. Figure 1 As shown.

[0026] A method for preparing a tungsten-copper composite material molded part according to this embodiment, the method steps are as follows: (1) Graphene oxide and anhydrous ethanol were mixed at a ratio of 1 mg: 1 mL and dissolved and dispersed in ultrasound for 30 min to obtain a graphene oxide dispersion. Tungsten powder, nickel powder, tungsten carbide powder, and graphene oxide dispersion were placed in a ball mill jar for wet ball milling and mixing. The grinding beads were made of tungsten carbide, with a ball-to-powder mass ratio of 20:1. Anhydrous ethanol was used as the grinding medium, accounting for 50% of the volume of the ball mill jar. The ball milling speed was 250 r / min, and the ball milling time was 25 h. The mixture was milled until homogeneous. Then, the anhydrous ethanol, grinding beads, and mixed powder were separated by a sieve. The mixed powder was dried in a vacuum oven at 60 ℃ for 12 h to obtain modified tungsten powder. (2) The modified tungsten powder, tungsten powder and copper powder obtained in step (1) are mixed to obtain metal powder. Phenolic resin solution is added to metal powder and stirred at 100 r / min for 1 h to mix evenly. Then it is placed in a vacuum oven and dried at 70 ℃ for 8 h. The composite powder is obtained by sieving through an 80 mesh sieve. (3) The composite powder prepared in step (2) is loaded into a circular pressing mold for molding to obtain a compact with a density of 12.5 g / cm³. 3 Composite material green blanks; (4) The composite material green blank prepared in step (3) is placed into a crucible, a copper block is placed in it, and hydrogen is passed through a protective atmosphere furnace for sintering and melting. The temperature is raised to 700 ℃ at a heating rate of 25 ℃ / min and held for 30 min; then the temperature is raised to 1100 ℃ at a heating rate of 20 ℃ / min and held for 40 min; finally, the temperature is raised to 1390 ℃ at a heating rate of 20 ℃ / min and held for 60 min to obtain a tungsten-copper composite material molded part. The molded part is cooled with the furnace and taken out. It is a tungsten-copper composite material ring with an outer diameter of 150 mm, an inner diameter of 60 mm, and a thickness of 6 mm, as shown in the figure. Figure 1 As shown.

[0027] The tungsten-copper composite ring-shaped part prepared in this embodiment was observed and its performance was tested as follows: (1) Observation by scanning electron microscope (SEM) The tungsten-copper composite ring was observed by SEM, and the results are as follows: Figure 2 As shown, from Figure 2 As can be seen from the data, the tungsten-copper composite material ring has a uniform structure and no obvious pores. (2) Performance testing The density, hardness, and electrical conductivity of the tungsten-copper composite ring were tested, and the test results are shown in Table 1.

[0028] Table 1

[0029] Example 2 A tungsten-copper composite material molded part, wherein the raw materials of the molding agent are composed of a tungsten source, a copper source and a molding agent, wherein, based on the total mass of tungsten and copper in the molded part being 100%, the mass fraction of tungsten is 90% and the mass fraction of copper is 10%; the molding agent is polyvinyl alcohol and paraffin wax, wherein the amount of polyvinyl alcohol is 1% of the total mass of the tungsten source and the copper source, and the amount of paraffin wax is 1% of the total mass of the tungsten source and the copper source.

[0030] The tungsten source is composed of modified tungsten powder and tungsten powder in a mass ratio of 3:1; Of the copper in the molded part, 10% by mass of the copper comes from copper blocks used in an amount 1.2 times that of the molded part.

[0031] Taking the total mass of the modified tungsten powder raw material as 100%, the individual components and their mass fractions are as follows: Activating element 1%, Tungsten carbide 0.8%, 0.05% graphene oxide Tungsten powder 98.15%; The activating element is nickel powder; Tungsten carbide powder and graphene oxide are used as reinforcing phases.

[0032] The molded part is a cuboid made of tungsten-copper composite material with a length of 55 mm, a width of 44 mm, and a thickness of 24 mm.

[0033] A method for preparing the tungsten-copper composite material described in this embodiment, comprising the following steps: (1) Graphene oxide and anhydrous ethanol were mixed at a ratio of 1 mg: 2 mL and dissolved and dispersed under ultrasound for 20 min to obtain a graphene oxide dispersion. Tungsten powder, nickel powder, tungsten carbide powder, and graphene oxide dispersion were placed in a ball mill jar for wet ball milling and mixing. The grinding beads were made of tungsten carbide, with a ball-to-powder mass ratio of 20:1. Anhydrous ethanol was used as the grinding medium, accounting for 40% of the volume of the ball mill jar. The ball milling speed was 200 r / min, and the ball milling time was 20 h. The mixture was milled and mixed evenly. Then, the anhydrous ethanol, grinding beads, and mixed powder were separated by a sieve. The mixed powder was dried in a vacuum oven at 50 ℃ for 12 h to obtain modified tungsten powder. (2) The modified tungsten powder and tungsten powder obtained in step 1 are mixed to obtain metal powder. The metal powder is added to the molding agent solution and stirred at 50 r / min for 2 h to mix evenly. Then it is placed in a vacuum oven and dried at 60 ℃ for 6 h. The composite powder is obtained by sieving through an 80 mesh screen. The molding agent solution is obtained by mixing paraffin solution and polyvinyl alcohol solution. (3) The composite powder prepared in step (2) is loaded into a rectangular compression mold for molding to obtain a compact with a density of 15.0 g / cm³. 3 Composite material green blanks; (4) The composite material green blank prepared in step (3) is placed into a crucible, a copper block is placed in it, and hydrogen is passed through the furnace for sintering and melting. The temperature is raised to 800 ℃ at a heating rate of 30 ℃ / min and held for 30 min; then the temperature is raised to 1050 ℃ at a heating rate of 25 ℃ / min and held for 40 min; finally the temperature is raised to 1400 ℃ at a heating rate of 20 ℃ / min and held for 90 min to obtain a tungsten copper composite material molded part. The molded part is cooled with the furnace and taken out. It is a tungsten copper composite material cuboid with a length of 55 mm, a width of 44 mm and a thickness of 24 mm.

[0034] The tungsten-copper composite cuboid prepared in this embodiment was observed and its performance was tested as follows: (1) Observation by scanning electron microscope (SEM) SEM observation of the tungsten-copper composite cuboid showed that the prepared tungsten-copper composite material had a uniform structure and no obvious pores. (2) Performance testing The density, hardness, and electrical conductivity of the tungsten-copper composite cuboid were tested, and the test results are shown in Table 2.

[0035] Table 2

[0036] Example 3 A tungsten-copper composite material molded part, wherein the raw materials of the molding agent are composed of a tungsten source, a copper source and a molding agent, wherein, based on the total mass of tungsten and copper in the molded part being 100%, the mass fraction of tungsten is 90% and the mass fraction of copper is 10%; the molding agent is nitrile rubber, paraffin wax and polyvinyl alcohol, wherein the amount of nitrile rubber is 1% of the total mass of the tungsten source and copper source, the amount of paraffin wax is 2% of the total mass of the tungsten source and copper source, and the amount of polyvinyl alcohol is 0.5% of the total mass of the tungsten source and copper source.

[0037] The tungsten source is composed of modified tungsten powder and tungsten powder in a mass ratio of 4:1; Of the copper in the molded part, 10% by mass of the copper comes from copper blocks used in an amount 1.2 times that of the molded part.

[0038] Taking the total mass of the modified tungsten powder raw material as 100%, the individual components and their mass fractions are as follows: Activating element 1.5%, tungsten carbide 1%, 0.08% graphene oxide Tungsten powder 97.42%; The activating element is nickel powder; Tungsten carbide powder and graphene oxide are used as reinforcing phases.

[0039] The molded part is a tungsten-copper composite cuboid with a length of 44 mm, a width of 34 mm, and a thickness of 22 mm.

[0040] A method for preparing the tungsten-copper composite material described in this embodiment, comprising the following steps: (1) Graphene oxide and anhydrous ethanol were mixed at a ratio of 2 mg: 1 mL and dissolved and dispersed under ultrasound for 60 min to obtain a graphene oxide dispersion. Tungsten powder, nickel powder, tungsten carbide powder, and graphene oxide dispersion were placed in a ball mill jar for wet ball milling and mixing. The grinding beads were made of tungsten carbide, with a ball-to-powder mass ratio of 40:1. Anhydrous ethanol was used as the grinding medium, accounting for 60% of the volume of the ball mill jar. The ball milling speed was 400 r / min, and the ball milling time was 30 h. The mixture was milled and mixed evenly. Then, the anhydrous ethanol, grinding beads, and mixed powder were separated by a sieve. The mixed powder was dried in a vacuum oven at 70 ℃ for 6 h to obtain modified tungsten powder. (2) The modified tungsten powder obtained in step (1) is mixed with tungsten powder to obtain metal powder. The metal powder is added to the molding agent solution and stirred at 150 r / min for 1 h to mix evenly. Then it is placed in a vacuum oven and dried at 80 ℃ for 8 h. The powder is then sieved through an 80-mesh sieve to obtain composite powder. The molding agent solution is obtained by mixing commercially available liquid nitrile rubber, paraffin solution and polyvinyl alcohol solution. (3) The composite powder prepared in step (2) is loaded into a rectangular compression mold for molding to obtain a compact with a density of 15.0 g / cm³. 3 Rectangular composite material green blank; (4) The composite material green blank prepared in step (3) is placed into a crucible, a copper block is placed in it, and hydrogen is passed through the furnace for sintering and melting. The temperature is raised to 900 ℃ at a heating rate of 35 ℃ / min and held for 30 min; then the temperature is raised to 1100 ℃ at a heating rate of 25 ℃ / min and held for 30 min; finally the temperature is raised to 1450 ℃ at a heating rate of 25 ℃ / min and held for 70 min to obtain a tungsten copper composite material molded part. The molded part is cooled with the furnace and taken out. It is a tungsten copper composite material cuboid with a length of 44 mm, a width of 34 mm and a thickness of 22 mm.

[0041] The tungsten-copper composite cuboid prepared in this embodiment was observed and its performance was tested as follows: (1) Observation by scanning electron microscope (SEM) SEM observation of the tungsten-copper composite cuboid showed that the prepared tungsten-copper composite material had a uniform structure and no obvious pores. (2) Performance testing The density, hardness, and electrical conductivity of the tungsten-copper composite cuboid were tested, and the test results are shown in Table 3.

[0042] Table 3

[0043] Example 4 A tungsten-copper composite material molded part, wherein the molding agent is composed of a tungsten source, a copper source, and a molding agent, wherein, based on the total mass of tungsten and copper in the molded part being 100%, the mass fraction of tungsten is 80% and the mass fraction of copper is 20%; the molding agent is polyvinyl alcohol, and the amount used is 1.5% of the total mass of the tungsten source and the copper source; The tungsten source is composed of modified tungsten powder and tungsten powder in a mass ratio of 3:1; Of the copper in the molded part, 8% by mass of copper comes from copper powder of equal mass, and 12% by mass of copper comes from copper blocks of 1.2 times mass.

[0044] Taking the total mass of the modified tungsten powder raw material as 100%, the individual components and their mass fractions are as follows: Activating element 0.7%, Tungsten carbide 1.5%, 0.05% graphene oxide 97.75% tungsten powder; The activating element is nickel powder; Tungsten carbide powder and graphene oxide are used as reinforcing phases.

[0045] The molded part is a circular part of tungsten-copper composite material with a diameter of 131 mm and a thickness of 4 mm.

[0046] A method for preparing a tungsten-copper composite material molded part according to this embodiment, the method steps are as follows: (1) Graphene oxide and anhydrous ethanol were mixed at a ratio of 1 mg: 1 mL and dissolved and dispersed in ultrasound for 40 min to obtain a graphene oxide dispersion. Tungsten powder, nickel powder, tungsten carbide powder, and graphene oxide dispersion were placed in a ball mill jar for wet ball milling and mixing. The grinding beads were made of tungsten carbide, with a ball-to-powder mass ratio of 45:1. Anhydrous ethanol was used as the grinding medium, accounting for 55% of the volume of the ball mill jar. The ball milling speed was 350 r / min, and the ball milling time was 48 h. The mixture was milled and homogeneous. Then, the anhydrous ethanol, grinding beads, and mixed powder were separated by sieve. The mixed powder was dried in a vacuum oven at 75 ℃ for 12 h to obtain modified tungsten powder. (2) The modified tungsten powder, tungsten powder and copper powder obtained in step (1) are mixed to obtain metal powder. The metal powder is added to polyvinyl alcohol solution and stirred at 80 r / min for 3 h to mix evenly. Then it is placed in a vacuum oven and dried at 70 ℃ for 6 h. The composite powder is obtained by sieving through an 80 mesh sieve. (3) The composite powder prepared in step (2) is loaded into a circular pressing mold for molding to obtain a pressed blank with a density of 13.1 g / cm³. 3 Circular composite material green blank; (4) The composite material green blank prepared in step (3) is placed into a crucible, a copper block is placed in it, and hydrogen is passed through the furnace for sintering and melting. The temperature is raised to 750 ℃ ​​at a heating rate of 15 ℃ / min and held for 60 min; then the temperature is raised to 1050 ℃ at a heating rate of 25 ℃ / min and held for 30 min; finally the temperature is raised to 1300 ℃ at a heating rate of 25 ℃ / min and held for 120 min to obtain a tungsten copper composite material molded part. The molded part is cooled with the furnace and taken out. It is a tungsten copper composite material circular part with a diameter of 131 mm and a thickness of 4 mm.

[0047] The tungsten-copper composite circular part prepared in this embodiment was observed and its performance was tested as follows: (1) Observation by scanning electron microscope (SEM) SEM observation of the circular tungsten-copper composite material showed that the prepared tungsten-copper composite material had a uniform structure and no obvious pores. (2) Performance testing The density, hardness, and electrical conductivity of the tungsten-copper composite circular part were tested, and the test results are shown in Table 4.

[0048] Table 4

[0049] Example 5 A tungsten-copper composite material molded part, wherein the molding agent is composed of a tungsten source, a copper source, and a molding agent, wherein, based on the total mass of tungsten and copper in the molded part being 100%, the mass fraction of tungsten is 60% and the mass fraction of copper is 40%; the molding agent is phenolic resin and polyvinyl alcohol, wherein the amount of phenolic resin is 2% of the total mass of the tungsten and copper sources, and the amount of polyvinyl alcohol is 2% of the total mass of the tungsten and copper sources; The tungsten source is composed of modified tungsten powder and tungsten powder in a mass ratio of 1:1; Of the copper in the molded part, 28% by mass comes from copper powder of equal mass, and 12% by mass comes from copper blocks of 1.2 times mass.

[0050] Taking the total mass of the modified tungsten powder raw material as 100%, the individual components and their mass fractions are as follows: Activating element 1%, Tungsten carbide 0.7%, Graphene oxide 0.02%, Tungsten powder 98.28%; The activating element is nickel powder; Tungsten carbide powder and graphene oxide are used as reinforcing phases; The molded part is a circular part of tungsten-copper composite material with a diameter of 95 mm and a thickness of 6 mm.

[0051] A method for preparing a tungsten-copper composite material molded part according to this embodiment, the method steps are as follows: (1) Graphene oxide and anhydrous ethanol were mixed at a ratio of 1 mg: 1 mL and dissolved and dispersed in ultrasound for 30 min to obtain a graphene oxide dispersion. Tungsten powder, nickel powder, tungsten carbide powder, and graphene oxide dispersion were placed in a ball mill jar for wet ball milling and mixing. The grinding beads were made of tungsten carbide, with a ball-to-powder mass ratio of 30:1. Anhydrous ethanol was used as the grinding medium, accounting for 50% of the volume of the ball mill jar. The ball milling speed was 200 r / min, and the ball milling time was 40 h. The mixture was ball-milled until uniform. Then, the anhydrous ethanol, grinding beads, and mixed powder were separated by sieve. The mixed powder was dried in a vacuum oven at 70 ℃ for 20 h to obtain modified tungsten powder. (2) The modified tungsten powder, tungsten powder and copper powder obtained in step (1) are mixed to obtain metal powder. The metal powder is added to the molding agent solution and stirred at 50 r / min for 2 h to mix evenly. Finally, it is placed in a vacuum oven and dried at 70 ℃ for 4 h. The powder is then sieved through an 80 mesh screen to obtain composite powder. The molding agent solution is prepared by mixing phenolic resin solution and polyvinyl alcohol solution. (3) The composite powder prepared in step (2) is loaded into a circular pressing mold for molding to obtain a pressed blank with a density of 10.1 g / cm³. 3 Circular composite material green blanks; (4) The composite material green blank prepared in step (3) is placed into a crucible, a copper block is placed in it, and hydrogen is passed through the furnace for sintering and melting. The temperature is raised to 850 ℃ at a heating rate of 20 ℃ / min and held for 60 min; then the temperature is raised to 1000 ℃ at a heating rate of 15 ℃ / min and held for 30 min; finally the temperature is raised to 1330 ℃ at a heating rate of 20 ℃ / min and held for 100 min to obtain a tungsten copper composite material molded part. The molded part is cooled with the furnace and taken out. It is a tungsten copper composite material circular part with a diameter of 95 mm and a thickness of 6 mm.

[0052] The tungsten-copper composite circular part prepared in this embodiment was observed and its performance was tested as follows: (1) Observation by scanning electron microscope (SEM) SEM observation of the circular tungsten-copper composite material showed that the prepared tungsten-copper composite material had a uniform structure and no obvious pores. (2) Performance testing The density, hardness, and electrical conductivity of the tungsten-copper composite circular part were tested, and the test results are shown in Table 5.

[0053] Table 5

Claims

1. A tungsten-copper composite material molded part, characterized in that: The raw materials for the molded part consist of a tungsten source, a copper source, and a molding agent; based on the total mass of tungsten and copper in the molded part being 100%, the mass fraction of tungsten is 50% to 93%, and the mass fraction of copper is 7% to 50%; the amount of molding agent used is 0.5% to 6% of the total mass of the tungsten and copper sources. The tungsten source consists of modified tungsten powder and tungsten powder. Based on the mass of the tungsten source being 100%, the mass fraction of modified tungsten powder is 50% to 80%, and the mass fraction of tungsten powder is 20% to 50%. When the mass fraction of tungsten in the molded part is above 85% and the mass fraction of copper is below 15%, the copper source is a copper block, and the amount of copper block used is 1.2 times the copper content in the molded part. When the mass fraction of tungsten in the molded part is less than 85% and the mass fraction of copper is more than 15%, the copper source is composed of copper powder and copper blocks; the ratio of the copper mass fraction derived from copper powder to copper blocks is 1:4 to 4:1; when the copper source is copper blocks, the amount of copper blocks used is 1.2 times the corresponding copper content. The molding agent is at least one of paraffin wax, phenolic resin, polyvinyl alcohol, and nitrile rubber; Taking the total mass of the modified tungsten powder raw material as 100%, the individual components and their mass fractions are as follows: Activating elements: 0.35% ~ 2% Tungsten carbide 0.2% ~ 2%, Graphene oxide 0.01% ~ 0.1%, Tungsten powder balance; The activating element is at least one of iron powder, nickel powder, and cobalt powder.

2. A tungsten-copper composite material molded part according to claim 1, characterized in that: Based on the total mass of tungsten and copper in the molded part being 100%, the mass fraction of tungsten is 60% to 90%, and the mass fraction of copper is 10% to 40%; the amount of molding agent used is 1.5% to 4% of the total mass of tungsten and copper sources.

3. A tungsten-copper composite material molded part according to claim 1 or 2, characterized in that: When the mass fraction of tungsten in the molded part is 90% and the mass fraction of copper is 10%, the copper source is a copper block; When the mass fraction of tungsten in the molded part is 60% to 80% and the mass fraction of copper is 20% to 40%, the copper source consists of copper powder and copper blocks.

4. A tungsten-copper composite material molded part according to claim 1 or 2, characterized in that: When the mass fraction of tungsten in the molded part is less than 85% and the mass fraction of copper is more than 15%, the copper source is composed of copper powder and copper blocks; the ratio of the copper mass fraction derived from copper powder and copper blocks is 2:3 to 7:

3.

5. A tungsten-copper composite material molded part according to claim 1 or 2, characterized in that: Taking the total mass of the modified tungsten powder raw material as 100%, the individual components and their mass fractions are as follows: Activating elements: 0.7% ~ 1.5% Tungsten carbide 0.25% ~ 1.5%, Graphene oxide 0.02% ~ 0.08%, Tungsten powder balance; The activating element is nickel powder.

6. A tungsten-copper composite material molded part according to claim 1 or 2, characterized in that: The molded part is a large-sized molded part with a diameter of 90 mm to 150 mm or a thickness of 15 mm to 30 mm.

7. A tungsten-copper composite material molded part according to claim 6, characterized in that: The molded part is a large-sized molded part with a diameter of 95 mm to 150 mm or a thickness of 22 mm to 24 mm.

8. A method for preparing a tungsten-copper composite material molded part according to any one of claims 1 to 7, characterized in that: (1) Tungsten powder, activating element, tungsten carbide powder and graphene oxide dispersion are mixed, then mixed evenly by wet ball milling, then separated and dried to obtain modified tungsten powder; (2) When the copper source is a copper block, the modified tungsten powder and tungsten powder are mixed to obtain metal powder, which is added to the molding agent solution, stirred and mixed evenly, and then dried and sieved to obtain composite powder; When the copper source consists of copper powder and copper blocks, the modified tungsten powder, tungsten powder and copper powder are mixed to obtain metal powder, which is then added to the molding agent solution, stirred and mixed evenly, and then dried and sieved to obtain composite powder. (3) The composite powder is loaded into a pressing mold and molded to obtain a composite material green body; (4) The raw material blank is placed into a sintering and melting container, a copper block is placed in it, and hydrogen gas is passed through for sintering and melting to obtain a tungsten copper composite material molded part.

9. The method for preparing a tungsten-copper composite material molded part according to claim 8, characterized in that: In step (1): The graphene oxide dispersion was obtained by dissolving and dispersing graphene oxide in anhydrous ethanol; The wet ball milling uses cemented carbide grinding balls with a ball-to-material mass ratio of 5:1 to 50:

1. The grinding media is anhydrous ethanol, which accounts for 40% to 80% of the volume of the grinding jar. The grinding speed is 100 r / min to 500 r / min, and the grinding time is 5 h to 48 h. The drying method is vacuum drying, the drying temperature is 50 ℃ ~ 80 ℃, and the drying time is 4 h ~ 24 h; In step (2): During mixing, the stirring rate is 20 r / min ~ 200 r / min, and the stirring time is 20 min ~ 4 h; The drying method is vacuum drying, with a drying temperature of 50 ℃ ~ 80 ℃ and a drying time of 4 h ~ 24 h; In step (4): The specific sintering and melting conditions are as follows: heat to 700℃~900℃ at a heating rate of 10℃ / min~35℃ / min, hold for 30 min~60 min; then heat to 1000℃~1100℃ at a heating rate of 10℃ / min~35℃ / min, hold for 30 min~60 min; finally heat to 1200℃~1450℃ at a heating rate of 10℃ / min~35℃ / min, hold for 30 min~120 min; thus obtaining a tungsten-copper composite material molded part.

10. The method for preparing a tungsten-copper composite material molded part according to claim 9, characterized in that: In step (1): The ball-to-material mass ratio is 20:1 to 45:1, the ball milling medium is anhydrous ethanol, which accounts for 40% to 60% of the ball mill jar volume, the ball milling speed is 200 r / min to 400 r / min, and the ball milling time is 20 h to 48 h. The drying temperature is 50 ℃ ~ 75 ℃, and the drying time is 6 h ~ 20 h; In step (2): The stirring rate is 50 r / min ~ 150 r / min, and the stirring time is 1 h ~ 3 h; The drying temperature is 60℃ ~ 80℃, and the time is 4 h ~ 8 h; In step (4): The specific conditions for sintering and melting are as follows: heat to 700℃~900℃ at a heating rate of 15℃ / min~35℃ / min, hold for 30 min~60 min; then heat to 1000℃~1100℃ at a heating rate of 15℃ / min~25℃ / min, hold for 30 min~40 min; finally heat to 1300℃~1450℃ at a heating rate of 20℃ / min~25℃ / min, hold for 60 min~120 min.

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