W-Cu composite material with component continuous gradient structure and preparation method of W-Cu composite material

Abstract

The invention discloses a W-Cu composite material with a component continuous gradient structure and a preparation method of the W-Cu composite material. The preparation method comprises the following steps: step 1, preparing a feed A and a feed B from W powder with different particle sizes; 2, the feed A and the feed B are added into a three-screw double-component single-nozzle powder extrusion device to be printed and extruded, and continuous gradient structure printing green bodies with different particle size W contents are obtained; 3, the obtained continuous gradient structure printing green bodies with different particle sizes and W contents are sequentially subjected to solvent degreasing, drying and thermal degreasing treatment, and continuous gradient structure degreasing green bodies are obtained; 4, the obtained continuous gradient structure degreased blank is sintered, and a continuous gradient structure sintered blank is obtained; and 5, the obtained continuous gradient structure sintering blank is subjected to copper infiltration treatment, and the W-Cu composite material of the component continuous gradient structure is obtained. By means of the method, the W-Cu composite material of the continuous gradient structure of the components can be prepared, wherein the W-Cu composite material has high surface arc ablation resistance and overall high electric conduction and heat conduction performance at the same time.

Description

Technical Field

[0001] This invention belongs to the technical field of composite material preparation methods, specifically relating to W-Cu composite materials with a continuous composition gradient structure, and also to a method for preparing W-Cu composite materials with a continuous composition gradient structure. Background Technology

[0002] In power systems, contacts, as core components of circuit breakers—critical equipment for controlling grid switching—must withstand arc erosion, mechanical wear, and high-current surges during frequent opening and closing operations. Therefore, the materials required for these contacts must possess extremely high resistance to welding, arc erosion, conductivity, and thermal stability. Tungsten-copper composites (W-Cu composites) are ideal materials for contacts in ultra-high voltage and extra-high voltage circuit breakers because they combine the high melting point (3422℃) and excellent arc erosion resistance of tungsten with the high conductivity and good machinability of copper.

[0003] Currently, traditional contact fabrication processes mainly employ powder metallurgy and melt infiltration methods. These methods typically produce homogeneous or layered W-Cu contact materials, making it difficult to form a continuous gradient structure with controllable performance within the material. Facing increasingly demanding service environments, the contacts exhibit insufficient surface resistance to arc erosion during operation, while the strength of the central region is not fully utilized, failing to meet future service requirements. While additive manufacturing technology, which has emerged in recent years, can achieve continuous gradient structure fabrication, for W-Cu material systems, the significant difference in melting points between W and Cu leads to either excessive energy input causing Cu phase vaporization and volatilization, or insufficient energy resulting in numerous voids between W particles. Consequently, the prepared W-Cu composite materials cannot simultaneously meet the requirements of high surface resistance to arc erosion and high overall electrical and thermal conductivity. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing W-Cu composite materials with a continuous compositional gradient structure, which can produce W-Cu composite materials with both high surface resistance to arc ablation and high overall electrical and thermal conductivity.

[0005] Another object of the present invention is to provide a W-Cu composite material with a continuous gradient structure.

[0006] The technical solution adopted in this invention is a method for preparing W-Cu composite materials with a continuous compositional gradient structure, the steps of which are as follows: Step 1: Prepare feed A and feed B using W powder of different particle sizes; Step 2: Feed A and feed B are added to a three-screw bicomponent single-nozzle powder extrusion device for printing and extrusion to obtain a continuous gradient structure printing green body with different particle sizes and W contents. Step 3: The obtained continuous gradient structure printing green bodies with different particle sizes and W contents are subjected to solvent degreasing, drying and thermal degreasing treatment in sequence to obtain continuous gradient structure degreased green bodies; Step 4: Place the obtained continuous gradient structure degreased blank into a sintering furnace for sintering to obtain a continuous gradient structure sintered blank. Step 5: The obtained continuous gradient structure sintered blank is subjected to copper infiltration treatment to obtain a W-Cu composite material with a continuous gradient structure.

[0007] The invention is further characterized by: The specific process of step 1 is as follows: Step 1.1: Add the binder and W powder of a single particle size to a mixer at a temperature of 130℃~170℃ and mix and mix for 2h~5h to obtain feed A with a powder volume loading rate of 40%~55%; Step 1.2 Add the binder and another type of single-particle-size W powder to a mixer at a temperature of 130℃~170℃ and mix and mix for 2h~5h to obtain feed B with a powder volume loading rate of 40%~55%.

[0008] In step 1.1, the particle size of W powder is one of 400 nm, 1 μm, and 6 μm. In step 1.2, the particle size of W powder is one of 400 nm, 1 μm, and 6 μm, and the particle size of W powder in step 1.2 is completely different from that in step 1.1.

[0009] The adhesive is composed of the following substances by mass percentage: 50%–70% paraffin wax, 20%–40% polyethylene, 5%–15% ethylene-vinyl acetate copolymer, and 1%–5% stearic acid, with the sum of the mass percentages of the above components being 100%.

[0010] The particle size of both feed A and feed B is 3mm~6mm.

[0011] In step 2, the heating temperature of feed A and feed B during the printing extrusion process is 130℃~200℃.

[0012] In step 3, the solvent degreasing process is as follows: a stainless steel mesh frame is set up in a glass beaker, and n-heptane solvent is added to the glass beaker. The glass beaker is then placed in a water bath at a temperature of 40℃~60℃ and heated. Green bodies of continuous gradient structure printing with different particle sizes and W content are placed into the glass beaker in the water bath for degreasing for 20h~100h. After the degreasing is completed, the green bodies of continuous gradient structure printing with different particle sizes and W content are transferred to kerosene and soaked for 10min~60min. They are then taken out and air-dried naturally for 2h~6h. In step 3, the drying temperature is 50℃~80℃, and the drying time is 6h~12h; In step 3, thermal degreasing is carried out in an argon atmosphere at a temperature of 100℃ to 700℃, a heating rate of 0.1℃ / min to 2℃ / min, and a holding time of 1h to 4h.

[0013] In step 4, sintering is carried out in a vacuum sintering furnace at a temperature of 1200℃~1500℃, a holding time of 1h~4h, and a heating rate of 5℃ / min~15℃ / min.

[0014] In step 5, the temperature for copper infiltration is 1100℃~1400℃, and the holding time is 1~4 h.

[0015] Another technical solution adopted in this invention is a W-Cu composite material with a continuous gradient structure, which is prepared by the preparation method of W-Cu composite material with a continuous gradient structure.

[0016] The beneficial effects of this invention are as follows: The preparation method of the W-Cu composite material with a continuous gradient structure of the present invention uses W powder of different particle sizes to be fully mixed with a binder to form a feed. The binder in the feed changes the adhesion force between powder particles, making the powder particles more uniformly distributed. A three-screw two-component single-nozzle powder extrusion device is used to realize the two-component variable gradient extrusion molding and printing. After debinding, sintering and melt infiltration, a W-Cu composite material with a certain strength and a continuous gradient structure of the composition is obtained. The continuous gradient structure of the composition can achieve a good match between the local area performance and the overall performance of the composite material, and at the same time, it has high surface resistance to arc erosion and high overall electrical and thermal conductivity, which meets the high reliability service requirements of arc erosion resistance at the arc end and excellent overall conductivity when used as a contact. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the three-screw bicomponent single-nozzle powder extrusion device in the method of the present invention; Figure 2 Macroscopic morphology of green bodies with continuous gradient structures of different particle sizes and W contents obtained by the method of the present invention; Figure 3 This is a schematic diagram of the microstructure of the W-Cu composite material with a continuous gradient structure obtained by the method of the present invention.

[0018] In the diagram, 1. Feed hopper A, 2. Feed hopper B, 3. Hopper A, 4. Motor A, 5. Mixing bin, 6. Hopper B, 7. Motor B, 8. Motor C, 9. Screw A, 10. Screw B, 11. Screw C, 12. Nozzle. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] The preparation method of the W-Cu composite material with a continuous gradient structure according to the present invention comprises the following steps: Step 1: Prepare feed A and feed B using W powder of different particle sizes; The specific process is as follows: Step 1.1: Add the binder and W powder of a single particle size to a mixer at a temperature of 130℃~170℃ and mix and mix for 2h~5h to obtain feed A with a powder volume loading rate of 40%~55% and a particle size of 3mm~6mm. Among them, the particle size of W powder is one of 400nm, 1μm, and 6μm; Step 1.2 Add the binder and another single-particle-size W powder to a mixer at a temperature of 130℃~170℃ and mix and mix for 2h~5h to obtain feed B with a powder volume loading rate of 40%~55% and a particle size of 3mm~6mm. The particle size of the W powder is one of 400 nm, 1 μm, and 6 μm, and is completely different from the particle size of the W powder in step 1.1. In steps 1.1 and 1.2, the adhesive is composed of the following substances by mass percentage: 50%–70% paraffin wax, 20%–40% polyethylene, 5%–15% ethylene-vinyl acetate copolymer, and 1%–5% stearic acid, with the sum of the mass percentages of the above components being 100%. Step 2: Feed A and feed B are added to a three-screw bicomponent single-nozzle powder extruder for printing and extrusion, resulting in the following... Figure 2 The continuous gradient structure of different particle sizes and W contents shown is used to print green bodies; like Figure 1 As shown, the three-screw bicomponent single-nozzle powder extrusion device includes a feed hopper A1 and a feed hopper B2. The bottom of the feed hopper A1 is connected to a hopper A3. A motor A4 is connected to the outer wall of the hopper A3. The output shaft of the motor A4 extends into the hopper A3. The output shaft of the motor A4 is connected to a screw A9. A mixing chamber 5 is connected to the side wall of the hopper A3 opposite to the motor A4. The bottom of the mixing chamber 5 has a conical structure. The bottom of the feed hopper B2 is connected to a hopper B6. A motor B7 is connected to the outer wall of the hopper B6. The output shaft of the motor B7 extends into the hopper B6. The output shaft of the motor B7 is connected to a screw B10. The side wall of the hopper B6 opposite to the motor B7 is connected to the mixing chamber 5. A motor C8 is connected to the top of the mixing chamber 5. The output shaft of the motor C8 extends into the mixing chamber 5. The output shaft of the motor C8 is connected to a screw C11. A nozzle 12 is connected to the bottom of the mixing chamber 5. During the printing extrusion process, the heating temperature of feed A and feed B is 130℃~200℃. Step 3: The obtained continuous gradient structure printing green bodies with different particle sizes and W contents are subjected to solvent degreasing, drying and thermal degreasing treatment in sequence to obtain degreased green bodies with different particle sizes and W contents. The solvent degreasing process is as follows: a stainless steel mesh frame is set up inside a glass beaker, and n-heptane solvent is added to the glass beaker. The glass beaker is then placed in a water bath at a temperature of 40℃~60℃ and heated. Green bodies of continuous gradient structure printing with different particle sizes and W content are placed into the glass beaker in the water bath for degreasing for 20h~100h. After the degreasing is completed, the green bodies of continuous gradient structure printing with different particle sizes and W content are transferred to kerosene and soaked for 10min~60min. They are then taken out and air-dried naturally for 2h~6h. The drying temperature is 50℃~80℃, and the drying time is 6h~12h; The hot degreasing was carried out in an argon atmosphere at a temperature of 100℃ to 700℃, a heating rate of 0.1℃ / min to 2℃ / min, and a holding time of 1h to 4h. Step 4: Place the degreased green bodies with different particle sizes and W contents into a vacuum sintering furnace for sintering to obtain sintered green bodies with different particle sizes and W contents. The sintering temperature is 1200℃~1500℃, the holding time is 1h~4h, and the heating rate is 5℃ / min~15℃ / min. Step 5: The obtained sintered green bodies with a continuous gradient structure and different particle sizes and W contents are subjected to copper infiltration treatment to obtain the following... Figure 3 The W-Cu composite material shown has a continuous gradient composition structure. The specific process is as follows: A pure Cu block is placed on a continuous gradient sintered blank with different particle sizes and W contents. The temperature is raised to 1100℃~1400℃ to melt the Cu block. The Cu liquid penetrates into the pores of the W skeleton of the continuous gradient sintered blank. The holding time is 1h~4h to obtain a W-Cu composite material with a continuous gradient structure.

[0021] This invention uses tungsten powder of different particle sizes (400nm, 1μm, 6μm) as raw materials and a three-screw, two-component, single-nozzle powder extrusion device to achieve two-component feeding and single-channel mixed extrusion printing. The printer independently and precisely controls the feeding of two sets of tungsten powders of different particle sizes through dual feed cylinders. Dynamic mixing and extrusion solves the problem of directly printing refractory metal W. By altering the adhesion between powder particles using a binder in the feed, the powder particle distribution becomes more uniform. During the molding process, the feed ratio is precisely adjusted, decreasing the content of fine tungsten powder A from 100% to 0% and increasing the content of feed B from 0% to 100%. In the finer tungsten powder region, due to the numerous contact points between particles, a dense packing structure is formed, while in the coarser tungsten powder region, the large particle skeleton dominates, retaining more original pores. This creates a continuous gradient structure of tungsten skeleton with increasing porosity, simultaneously achieving gradient control of porosity, pore size, and density. During the debinding and sintering stages, the microstructure of the pores is precisely controlled by utilizing the differences in characteristics between coarse and fine tungsten powders. Regions with coarser tungsten powder particles, due to their smaller specific surface area and lower binder content, experience shorter volatilization paths during debinding and greater diffusion resistance during sintering, forming a high-porosity framework. Conversely, regions with finer tungsten powder particles, due to their larger specific surface area and more thorough binder coating, experience longer volatilization paths during debinding and stronger sintering driving force, forming a low-porosity, dense structure. In the melt infiltration process, based on the differences in capillary action of molten copper in different pore structures, a gradient increase in copper content and a continuous distribution of the copper phase are achieved in the material, endowing it with excellent electrical and thermal conductivity. Ultimately, a W-Cu composite material with a continuously gradient composition structure, achieving a perfect balance between surface arc erosion resistance and overall high electrical and thermal conductivity, is prepared.

[0022] Example 1 Step 1: Prepare feed A and feed B using W powder of different particle sizes; The specific process is as follows: Step 1.1: Add the binder and W powder with a single particle size of 6μm into a mixer at a temperature of 150℃ and mix for 3 hours to obtain feed A with a powder volume loading rate of 50% and a particle size of 6mm. Step 1.2 Add the binder and W powder with a particle size of 400 nm into a mixer at a temperature of 150 °C and mix for 3 hours to obtain feed B with a powder volume loading rate of 50% and a particle size of 6 mm. The adhesives in steps 1.1 and 1.2 are composed of the following substances by mass percentage: 60% paraffin wax, 30% polyethylene, 5% ethylene-vinyl acetate copolymer, and 5% stearic acid.

[0023] Step 2: Feed A and feed B are added to a three-screw bicomponent single-nozzle powder extrusion device for printing and extrusion to obtain a continuous gradient structure printing green body with different particle sizes and W contents. During the printing extrusion process, the heating temperature of feed A and feed B is 180℃. Step 3: The obtained continuous gradient structure printing green bodies with different particle sizes and W contents are subjected to solvent degreasing, drying and thermal degreasing treatment in sequence to obtain continuous gradient structure degreased green bodies; The solvent degreasing process is as follows: a stainless steel mesh frame is set up inside a glass beaker, and n-heptane solvent is added to the glass beaker. The glass beaker is then placed in a water bath at a temperature of 50°C and heated. Green bodies of continuous gradient structures with different particle sizes and W contents are placed into the glass beaker in the water bath for degreasing for 60 hours. The amount of n-heptane solvent added must cover the green bodies of continuous gradient structures with different particle sizes and W contents. After the degreasing process is completed, the green bodies of continuous gradient structures with different particle sizes and W contents are transferred to kerosene and soaked for 30 minutes. They are then taken out and air-dried for 4 hours. The drying temperature is 60℃, and the drying time is 8 hours; The hot degreasing was carried out in an argon atmosphere at a temperature of 500℃, a heating rate of 2℃ / min, and a holding time of 2h. Step 4: Place the obtained continuous gradient structure degreased blank into a vacuum sintering furnace for sintering to obtain a continuous gradient structure sintered blank. The sintering temperature was 1300℃, the holding time was 2h, and the heating rate was 15℃ / min. Step 5: The obtained continuous gradient structure sintered blank is subjected to copper infiltration treatment to obtain a W-Cu composite material with a continuous gradient structure. The specific process is as follows: A pure Cu block was placed on a continuous gradient sintered blank with different particle sizes and W contents. The temperature was raised to 1200℃ to melt the Cu block. The Cu liquid penetrated into the pores of the W skeleton of the continuous gradient sintered blank. The holding time was 2h to obtain a W-Cu composite material with a continuous gradient composition.

[0024] Example 2 Step 1: Prepare feed A and feed B using W powder of different particle sizes; The specific process is as follows: Step 1.1: Add the binder and W powder with a particle size of 1μm into a mixer at a temperature of 130℃ and mix for 5 hours to obtain feed A with a powder volume loading rate of 45% and a particle size of 3mm. Step 1.2 Add the binder and W powder with a particle size of 400nm into a mixer at a temperature of 130℃ and mix for 5 hours to obtain feed B with a powder volume loading rate of 45% and a particle size of 3mm. The adhesives in steps 1.1 and 1.2 are composed of the following substances by mass percentage: paraffin 70%, polyethylene 20%, ethylene-vinyl acetate copolymer 5%, and stearic acid 5%.

[0025] Step 2: Feed A and feed B are added to a three-screw bicomponent single-nozzle powder extrusion device for printing and extrusion to obtain a continuous gradient structure printing green body with different particle sizes and W contents. During the printing extrusion process, the heating temperature of feed A and feed B is 200℃. Step 3: The obtained continuous gradient structure printing green bodies with different particle sizes and W contents are subjected to solvent degreasing, drying and thermal degreasing treatment in sequence to obtain continuous gradient structure degreased green bodies; The solvent degreasing process is as follows: a stainless steel mesh frame is set up inside a glass beaker, and n-heptane solvent is added to the glass beaker. The glass beaker is then placed in a water bath at a temperature of 60°C and heated. Green bodies of continuous gradient structure printing with different particle sizes and W contents are placed into the glass beaker in the water bath for degreasing for 20 hours. The amount of n-heptane solvent added must cover the green bodies of continuous gradient structure printing with different particle sizes and W contents. After the process is completed, the green bodies of continuous gradient structure printing with different particle sizes and W contents are transferred to kerosene and soaked for 10 minutes. They are then taken out and air-dried for 6 hours. The drying temperature is 80℃, and the drying time is 6 hours; The hot degreasing was carried out in an argon atmosphere at a temperature of 100℃, a heating rate of 1℃ / min, and a holding time of 4h. Step 4: Place the obtained continuous gradient structure degreased blank into a vacuum sintering furnace for sintering to obtain a continuous gradient structure sintered blank. The sintering temperature was 1500℃, the holding time was 1h, and the heating rate was 15℃ / min. Step 5: The obtained continuous gradient structure sintered blank is subjected to copper infiltration treatment to obtain a W-Cu composite material with a continuous gradient structure. The specific process is as follows: A pure Cu block was placed on a continuous gradient sintered blank with different particle sizes and W contents. The temperature was raised to 1400℃ to melt the Cu block. The Cu liquid penetrated into the pores of the W skeleton of the continuous gradient sintered blank. The holding time was 1h to obtain a W-Cu composite material with a continuous gradient composition.

[0026] Example 3 Step 1: Prepare feed A and feed B using W powder of different particle sizes; The specific process is as follows: Step 1.1: Add the binder and W powder with a particle size of 6μm into a mixer at a temperature of 170℃ and mix for 2 hours to obtain feed A with a powder volume loading rate of 45% and a particle size of 5mm. Step 1.2 Add the binder and W powder with a particle size of 1μm to a mixer at a temperature of 170℃ and mix for 2 hours to obtain feed B with a powder volume loading rate of 45% and a particle size of 5mm. The adhesives in steps 1.1 and 1.2 are composed of the following substances by mass percentage: 50% paraffin wax, 40% polyethylene, 9% ethylene-vinyl acetate copolymer, and 1% stearic acid.

[0027] Step 2: Feed A and feed B are added to a three-screw bicomponent single-nozzle powder extrusion device for printing and extrusion to obtain a continuous gradient structure printing green body with different particle sizes and W contents. During the printing extrusion process, the heating temperature of feed A and feed B is 130℃. Step 3: The obtained continuous gradient structure printing green bodies with different particle sizes and W contents are subjected to solvent degreasing, drying and thermal degreasing treatment in sequence to obtain continuous gradient structure degreased green bodies; The solvent degreasing process is as follows: a stainless steel mesh frame is set up inside a glass beaker, and n-heptane solvent is added to the glass beaker. The glass beaker is then placed in a water bath at a temperature of 40°C and heated. Green bodies of continuous gradient structures with different particle sizes and W contents are placed into the glass beaker in the water bath for degreasing for 100 hours. The amount of n-heptane solvent added must cover the green bodies of continuous gradient structures with different particle sizes and W contents. After the degreasing process is completed, the green bodies of continuous gradient structures with different particle sizes and W contents are transferred to kerosene and soaked for 60 minutes. They are then taken out and air-dried for 2 hours. The drying temperature is 50℃, and the drying time is 12 hours. The hot degreasing was carried out in an argon atmosphere at a temperature of 700℃, a heating rate of 2℃ / min, and a holding time of 1h. Step 4: Place the obtained continuous gradient structure degreased blank into a vacuum sintering furnace for sintering to obtain a continuous gradient structure sintered blank. The sintering temperature was 1200℃, the holding time was 4h, and the heating rate was 5℃ / min. Step 5: The obtained continuous gradient structure sintered blank is subjected to copper infiltration treatment to obtain a W-Cu composite material with a continuous gradient structure. The specific process is as follows: A pure Cu block was placed on a continuous gradient sintered blank with different particle sizes and W contents. The temperature was raised to 1400℃ to melt the Cu block. The Cu liquid penetrated into the pores of the W skeleton of the continuous gradient sintered blank. The holding time was 1h to obtain a W-Cu composite material with a continuous gradient composition.

[0028] Example 4 Step 1: Prepare feed A and feed B using W powder of different particle sizes; The specific process is as follows: Step 1.1: Add the binder and W powder with a particle size of 1μm into a mixer at a temperature of 150℃ and mix and mix for 2 hours to obtain feed A with a powder volume loading rate of 50% and a particle size of 4mm. Step 1.2 Add the binder and W powder with a particle size of 400nm into a mixer at a temperature of 150℃ and mix and mix for 2 hours to obtain feed B with a powder volume loading rate of 50% and a particle size of 4mm. The adhesives in steps 1.1 and 1.2 are composed of the following substances by mass percentage: paraffin 60%, polyethylene 30%, ethylene-vinyl acetate copolymer 8%, and stearic acid 2%.

[0029] Step 2: Feed A and feed B are added to a three-screw bicomponent single-nozzle powder extrusion device for printing and extrusion to obtain a continuous gradient structure printing green body with different particle sizes and W contents. During the printing extrusion process, the heating temperature of feed A and feed B is 180℃. Step 3: The obtained continuous gradient structure printing green bodies with different particle sizes and W contents are subjected to solvent degreasing, drying and thermal degreasing treatment in sequence to obtain continuous gradient structure degreased green bodies; The solvent degreasing process is as follows: a stainless steel mesh frame is set up inside a glass beaker, and n-heptane solvent is added to the glass beaker. The glass beaker is then placed in a water bath at a temperature of 50°C and heated. Green bodies of continuous gradient structures with different particle sizes and W contents are placed into the glass beaker in the water bath for degreasing for 60 hours. The amount of n-heptane solvent added must cover the green bodies of continuous gradient structures with different particle sizes and W contents. After the degreasing process is completed, the green bodies of continuous gradient structures with different particle sizes and W contents are transferred to kerosene and soaked for 30 minutes. They are then taken out and air-dried for 4 hours. The drying temperature is 70℃, and the drying time is 8 hours; The hot degreasing was carried out in an argon atmosphere at a temperature of 500℃, a heating rate of 1℃ / min, and a holding time of 2h. Step 4: Place the obtained continuous gradient structure degreased blank into a vacuum sintering furnace for sintering to obtain a continuous gradient structure sintered blank. The sintering temperature was 1400℃, the holding time was 2h, and the heating rate was 15℃ / min. Step 5: The obtained continuous gradient structure sintered blank is subjected to copper infiltration treatment to obtain a W-Cu composite material with a continuous gradient structure. The specific process is as follows: A pure Cu block was placed on a continuous gradient sintered blank with different particle sizes and W contents. The temperature was raised to 1200℃ to melt the Cu block. The Cu liquid penetrated into the pores of the W skeleton of the continuous gradient sintered blank. The holding time was 2h to obtain a W-Cu composite material with a continuous gradient composition.

[0030] The W-Cu composite material with a continuous compositional gradient structure obtained in this embodiment has an electrical conductivity of 57.5% IACS, a hardness of 187 HB, and a breakdown strength of 7.2 × 10⁻⁶. 7 V / m.

[0031] Example 5 Step 1: Prepare feed A and feed B using W powder of different particle sizes; The specific process is as follows: Step 1.1: Add the binder and W powder with a particle size of 6μm into a mixer at a temperature of 150℃ and mix and mix for 2 hours to obtain feed A with a powder volume loading rate of 40% and a particle size of 4mm. Step 1.2 Add the binder and W powder with a particle size of 1μm into a mixer at a temperature of 150℃ and mix and mix for 2 hours to obtain feed B with a powder volume loading rate of 40% and a particle size of 4mm. The adhesives in steps 1.1 and 1.2 are composed of the following substances by mass percentage: paraffin 63%, polyethylene 20%, ethylene-vinyl acetate copolymer 15%, and stearic acid 2%.

[0032] Step 2: Feed A and feed B are added to a three-screw bicomponent single-nozzle powder extrusion device for printing and extrusion to obtain a continuous gradient structure printing green body with different particle sizes and W contents. During the printing extrusion process, the heating temperature of feed A and feed B is 180℃. Step 3: The obtained continuous gradient structure printing green bodies with different particle sizes and W contents are subjected to solvent degreasing, drying and thermal degreasing treatment in sequence to obtain continuous gradient structure degreased green bodies; The solvent degreasing process is as follows: a stainless steel mesh frame is set up inside a glass beaker, and n-heptane solvent is added to the glass beaker. The glass beaker is then placed in a water bath at a temperature of 50°C and heated. Green bodies of continuous gradient structures with different particle sizes and W contents are placed into the glass beaker in the water bath for degreasing for 60 hours. The amount of n-heptane solvent added must cover the green bodies of continuous gradient structures with different particle sizes and W contents. After the degreasing process is completed, the green bodies of continuous gradient structures with different particle sizes and W contents are transferred to kerosene and soaked for 30 minutes. They are then taken out and air-dried for 4 hours. The drying temperature is 70℃, and the drying time is 8 hours; The hot degreasing was carried out in an argon atmosphere at a temperature of 100℃, a heating rate of 0.1℃ / min, and a holding time of 4h. Step 4: Place the obtained continuous gradient structure degreased blank into a vacuum sintering furnace for sintering to obtain a continuous gradient structure sintered blank. The sintering temperature was 1400℃, the holding time was 2h, and the heating rate was 8℃ / min. Step 5: The obtained continuous gradient structure sintered blank is subjected to copper infiltration treatment to obtain a W-Cu composite material with a continuous gradient structure. The specific process is as follows: A pure Cu block was placed on a continuous gradient sintered blank with different particle sizes and W contents. The temperature was raised to 1100℃ to melt the Cu block. The Cu liquid penetrated into the pores of the W skeleton of the continuous gradient sintered blank. The holding time was 4h to obtain a W-Cu composite material with a continuous gradient composition.

[0033] The W-Cu composite material with a continuous compositional gradient structure obtained in this embodiment has an electrical conductivity of 52.7% IACS, a hardness of 217 HB, and a breakdown strength of 8.2 × 10⁻⁶. 7 V / m.

[0034] Example 6 Step 1: Prepare feed A and feed B using W powder of different particle sizes; The specific process is as follows: Step 1.1: Add the binder and W powder with a particle size of 6μm into a mixer at a temperature of 140℃ and mix for 4 hours to obtain feed A with a powder volume loading rate of 55% and a particle size of 5mm. Step 1.2 Add the binder and W powder with a particle size of 1μm into a mixer at a temperature of 140℃ and mix for 4 hours to obtain feed B with a powder volume loading rate of 55% and a particle size of 5mm. The adhesives in steps 1.1 and 1.2 are composed of the following substances by mass percentage: paraffin 70%, polyethylene 20%, ethylene-vinyl acetate copolymer 5%, and stearic acid 5%.

[0035] Step 2: Feed A and feed B are added to a three-screw bicomponent single-nozzle powder extrusion device for printing and extrusion to obtain a continuous gradient structure printing green body with different particle sizes and W contents. During the printing extrusion process, the heating temperature of feed A and feed B is 200℃. Step 3: The obtained continuous gradient structure printing green bodies with different particle sizes and W contents are subjected to solvent degreasing, drying and thermal degreasing treatment in sequence to obtain continuous gradient structure degreased green bodies; The solvent degreasing process is as follows: a stainless steel mesh frame is set up inside a glass beaker, and n-heptane solvent is added to the glass beaker. The glass beaker is then placed in a water bath at a temperature of 60°C and heated. Green bodies of continuous gradient structure printing with different particle sizes and W contents are placed into the glass beaker in the water bath for degreasing for 20 hours. The amount of n-heptane solvent added must cover the green bodies of continuous gradient structure printing with different particle sizes and W contents. After the process is completed, the green bodies of continuous gradient structure printing with different particle sizes and W contents are transferred to kerosene and soaked for 10 minutes. They are then taken out and air-dried for 6 hours. The drying temperature is 80℃, and the drying time is 6 hours; The hot degreasing was carried out in an argon atmosphere at a temperature of 100℃, a heating rate of 1℃ / min, and a holding time of 4h. Step 4: Place the obtained continuous gradient structure degreased blank into a vacuum sintering furnace for sintering to obtain a continuous gradient structure sintered blank. The sintering temperature was 1500℃, the holding time was 1h, and the heating rate was 15℃ / min. Step 5: The obtained continuous gradient structure sintered blank is subjected to copper infiltration treatment to obtain a W-Cu composite material with a continuous gradient structure. The specific process is as follows: A pure Cu block was placed on a continuous gradient sintered blank with different particle sizes and W contents. The temperature was raised to 1400℃ to melt the Cu block. The Cu liquid penetrated into the pores of the W skeleton of the continuous gradient sintered blank. The holding time was 1h to obtain a W-Cu composite material with a continuous gradient composition.

[0036] The W-Cu composite material with a continuous compositional gradient structure obtained in this embodiment has an electrical conductivity of 51.2% IACS, a hardness of 242 HB, and a breakdown strength of 8.5 × 10⁻⁶. 7 V / m.

Claims

1. A method for preparing W-Cu composite materials with a continuous compositional gradient structure, characterized in that, The steps are as follows: Step 1: Prepare feed A and feed B using W powder of different particle sizes; Step 2: Feed A and feed B are added to a three-screw bicomponent single-nozzle powder extrusion device for printing and extrusion to obtain a continuous gradient structure printing green body with different particle sizes and W contents. Step 3: The obtained continuous gradient structure printing green bodies with different particle sizes and W contents are subjected to solvent degreasing, drying and thermal degreasing treatment in sequence to obtain continuous gradient structure degreased green bodies; Step 4: Place the obtained continuous gradient structure degreased blank into a sintering furnace for sintering to obtain a continuous gradient structure sintered blank. Step 5: The obtained continuous gradient structure sintered blank is subjected to copper infiltration treatment to obtain a W-Cu composite material with a continuous gradient structure.

2. The method for preparing the W-Cu composite material with a continuous compositional gradient structure according to claim 1, characterized in that, The specific process of step 1 is as follows: Step 1.1: Add the binder and W powder of a single particle size to a mixer at a temperature of 130℃~170℃ and mix and mix for 2h~5h to obtain feed A with a powder volume loading rate of 40%~55%; Step 1.2 Add the binder and another type of single-particle-size W powder to a mixer at a temperature of 130℃~170℃ and mix and mix for 2h~5h to obtain feed B with a powder volume loading rate of 40%~55%.

3. The method for preparing the W-Cu composite material with a continuous compositional gradient structure according to claim 2, characterized in that, In step 1.1, the particle size of W powder is one of 400 nm, 1 μm, and 6 μm. In step 1.2, the particle size of W powder is one of 400 nm, 1 μm, and 6 μm, and the particle size of W powder in step 1.2 is completely different from that in step 1.

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4. The method for preparing the W-Cu composite material with a continuous compositional gradient structure according to claim 2, characterized in that, The adhesive is composed of the following substances by mass percentage: 50%–70% paraffin wax, 20%–40% polyethylene, 5%–15% ethylene-vinyl acetate copolymer, and 1%–5% stearic acid, with the sum of the mass percentages of the above components being 100%.

5. The method for preparing the W-Cu composite material with a continuous compositional gradient structure according to claim 1 or 2, characterized in that, The particle size of both feed A and feed B is 3mm~6mm.

6. The method for preparing the W-Cu composite material with a continuous compositional gradient structure according to claim 1, characterized in that, In step 2, the heating temperature of feed A and feed B during the printing extrusion process is 130℃~200℃.

7. The method for preparing the W-Cu composite material with a continuous compositional gradient structure according to claim 1, characterized in that, In step 3, the solvent degreasing process is as follows: a stainless steel mesh frame is set up in a glass beaker, and n-heptane solvent is added to the glass beaker. The glass beaker is then placed in a water bath at a temperature of 40℃~60℃ and heated. Green bodies of continuous gradient structure printing with different particle sizes and W content are placed into the glass beaker in the water bath for degreasing for 20h~100h. After the degreasing is completed, the green bodies of continuous gradient structure printing with different particle sizes and W content are transferred to kerosene and soaked for 10min~60min. They are then taken out and air-dried naturally for 2h~6h. In step 3, the drying temperature is 50℃~80℃, and the drying time is 6h~12h; In step 3, thermal degreasing is carried out in an argon atmosphere at a temperature of 100℃ to 700℃, a heating rate of 0.1℃ / min to 2℃ / min, and a holding time of 1h to 4h.

8. The method for preparing the W-Cu composite material with a continuous compositional gradient structure according to claim 1, characterized in that, In step 4, the sintering temperature is 1200℃~1500℃, the holding time is 1h~4h, and the heating rate is 5℃ / min~15℃ / min.

9. The method for preparing the W-Cu composite material with a continuous compositional gradient structure according to claim 1, characterized in that, In step 5, the temperature for copper infiltration is 1100℃~1400℃, and the holding time is 1~4 h.

10. A W-Cu composite material with a continuous compositional gradient structure, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 9.

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