Preparation method of copper / molybdenum copper / copper layered composite material

Abstract

The invention discloses a preparation method of a copper / molybdenum copper / copper layered composite material. The preparation method is specifically implemented according to the following steps: step 1, preparing a porous molybdenum skeleton by adopting electron beam selective melting forming; 2, the porous molybdenum framework prepared in the step 1 is pretreated, and then surface modification treatment is achieved through chemical nickel plating; 3, the porous molybdenum framework subjected to surface nickel plating in the step 2 is subjected to infiltration through an oxygen-free copper block, and a CPC infiltration ingot blank is obtained; and 4, the CPC infiltration ingot blank obtained in the step 3 is subjected to direct-current auxiliary hot pressing sintering, and the CPC layered composite material is obtained. The three-dimensional interpenetrating bicontinuous topological structure is prepared through selective electron beam melting forming and then infiltration, the heat conductivity of the material is improved, and then the metallurgical bonding interface strength is improved through the direct current auxiliary hot pressing sintering technology.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of layered composite material preparation, and relates to a copper / molybdenum copper / copper layered composite material preparation method. BACKGROUND

[0002] The copper / molybdenum copper / copper (CPC) layered composite material provides an ideal solution for realizing the matching of the thermal expansion coefficient with the semiconductor material and high-efficiency heat dissipation by structural design, combination of the high thermal conductivity of copper and the low expansion characteristics of molybdenum; in high heat flow application scenarios such as 5G communication base station core radio frequency devices, high-performance computing chip packaging, new energy vehicle power modules, etc., the CPC material gradually becomes one of the key materials for coping with local overheating and thermal cycle fatigue.

[0003] The excellent performance of the CPC material depends on the microstructure and interface metallurgical quality thereof, and the existing preparation technology faces intrinsic challenges due to the different physical properties of molybdenum and copper, which leads to the fact that the comprehensive performance thereof does not meet the expectation: firstly, in terms of interface combination, the two-dimensional plane interface formed by the traditional rolling or hot pressing process has weak combination and limited contact area, and the interface is easy to become a crack source under the action of thermal stress, and thus a stable heat transport channel cannot be constructed. Secondly, in terms of three-dimensional structure preparation, the conventional powder metallurgy + infiltration method is difficult to control the copper channel, the copper liquid has poor wettability to the molybdenum skeleton, and thus it is difficult to form a three-dimensional double-continuous structure with full penetration and low interface defects, which causes the internal heat conduction network to be blocked, and thus the heat transfer efficiency is seriously restricted. Finally, in terms of process synergistic regulation, the traditional hot pressing technology takes a long time and cannot synergistically improve the density and the comprehensive performance of the material, and at the same time, microcracks and internal stress are easily introduced due to the incoordination of the plastic deformation of the two phases, and thus it is difficult to form a high-strength interface.

[0004] Therefore, an integrated preparation technology capable of constructing a three-dimensional continuous structure and realizing precise regulation of the copper / molybdenum interface is urgently needed, so as to prepare a high-density composite material, and the high interface bonding strength and continuous heat conduction channel are optimized, the synergistic matching of the thermal conductivity and the thermal expansion coefficient of the CPC material is broken through, and technical support is provided for the development of the next generation of high-performance heat dissipation materials. SUMMARY

[0005] The purpose of the present application is to provide a copper / molybdenum copper / copper layered composite material preparation method, a three-dimensional interpenetrating double-continuous topological structure is prepared by electron beam selective melting forming and infiltration, the thermal conductivity of the material is improved, and the metallurgical bonding interface strength is improved by adopting the direct current assisted hot pressing sintering technology.

[0006] The technical scheme adopted by the present application is a copper / molybdenum copper / copper layered composite material preparation method, which is implemented according to the following steps: Step 1: preparing a porous molybdenum skeleton by electron beam selective melting forming; Step 2: after the porous molybdenum skeleton prepared in step 1 is pretreated, surface modification treatment is realized by chemical nickel plating. Step 3: The porous molybdenum skeleton with nickel plating in Step 2 is infiltrated with oxygen-free copper blocks to obtain CPC infiltrated ingot billet. Step 4: The CPC melt-infiltrating ingot obtained in Step 3 is subjected to DC-assisted hot pressing sintering to obtain CPC layered composite material.

[0007] Furthermore, step 1 specifically involves: Step 1.1, 3D modeling Based on a preset three-dimensional interpenetrating double continuous topology, a three-dimensional digital model of the molybdenum skeleton to be printed is constructed. Then, the three-dimensional digital model of the molybdenum skeleton is imported into the slicing software for slicing, and the generated slicing data is imported into the control system of the electron beam printing equipment. Step 1.2, spreading powder The dried spherical molybdenum powder is added to the powder cylinder for preparation before electron beam selective melting and forming. The substrate in the forming chamber is preheated to the preset temperature using an electron beam, and the powder in the powder cylinder is laid on the substrate using a scraper. Step 1.3, Print The powder is preheated using a defocused electron beam, and then selectively melted using a focused electron beam. After melting, the powder bed is kept warm using a defocused electron beam. Then, the scanning direction is rotated by 90°, and the substrate is lowered by one powder layer thickness. The scanning is repeated until the porous molybdenum skeleton is manufactured.

[0008] Furthermore, the three-dimensional interpenetrating double continuous topology in step 1.1 is a biomimetic microstructure with double continuous characteristics, specifically: a three-period minimal surface TPMS structure or a diamond lattice structure, etc.

[0009] Furthermore, the thickness of the slices in step 1.1 is 40 mm. ~80 .

[0010] Furthermore, in step 1.2, the spherical molybdenum powder has a particle size range of 45μm to 105μm, the substrate is a molybdenum plate, and the vacuum degree of the forming chamber reaches 10. -2 Helium is introduced at Pa, and the preheating temperature of the substrate is 1200℃~1400℃.

[0011] Furthermore, in step 1.3, the preheating scanning current for preheating the powder using a defocused electron beam is 12mA~30mA, and the preheating time is 10s~20s. Selective melting of powder is performed using a focused electron beam, specifically: the melting electron beam current is 10mA~20mA, the melting electron beam scanning speed is 0.5m / s~3m / s, and the electron beam spot diameter is controlled to be 100μm~225μm for scanning; After melting, the electron beam current for heat preservation of the powder bed using a decoupling electron beam is 12mA~30mA, and the heat preservation time is 5s~15s.

[0012] Furthermore, the preprocessing in step 2 specifically includes: After thoroughly washing the porous molybdenum skeleton in the pickling solution, it was rinsed repeatedly with alcohol until the surface of the porous molybdenum skeleton became neutral and then dried. The pickling solution consisted of 10%~13% nitric acid and 87%~90% deionized water. In step 2, the electroless nickel plating uses an electroless nickel plating solution with deionized water as the solvent. The solutes are dissolved in the solvent to prepare the electroless nickel plating solution. The solutes and their concentrations are as follows: nickel sulfate hexahydrate 100g / L~150g / L, nickel chloride 10g / L~30g / L, sodium sulfate 150g / L~200g / L and boric acid 20g / L~30g / L.

[0013] Furthermore, in step 2, the electroless nickel plating specifically involves heating the electroless nickel plating solution to 80°C~90°C and then immersing it in a pretreated porous molybdenum skeleton for 30min~60min to obtain a continuous and uniform nickel plating layer with a thickness of 3μm~10μm. Subsequently, the porous molybdenum skeleton is removed, cleaned with deionized water, and then dried.

[0014] Further, step 3 specifically involves: placing a graphite strip at the bottom of a graphite crucible, placing the nickel-plated porous molybdenum skeleton obtained in step 2 on the graphite strip, and placing an oxygen-free copper block of appropriate size on the porous molybdenum skeleton for melt infiltration to obtain a CPC melt-infiltrated ingot billet. The melting and infiltration process parameters are: temperature 1200℃~1500℃, holding time 3h~5h, and finally cooling to room temperature with the furnace, with hydrogen as the protective atmosphere.

[0015] Further, step 4 specifically involves subjecting the CPC melt-infiltrating ingot obtained in step 3 to DC-assisted hot pressing sintering. The process parameters for DC-assisted hot pressing sintering are: temperature 600℃~950℃, pressure 20MPa~40MPa, holding time 10min~30min, and cooling to room temperature in a vacuum furnace to obtain CPC layered composite material.

[0016] The beneficial effects of this invention are: This invention first utilizes electron beam printing technology to achieve precise design and manufacturing of a three-dimensional molybdenum skeleton topology. Based on this, chemical plating is used to modify the interface to improve wettability and bonding potential, constructing a dense, continuous nickel transition layer in situ on the inner and outer surfaces of the molybdenum skeleton. A fully interconnected, three-dimensional, interpenetrating, double-continuous, high-throughput thermally conductive network is constructed using a melt infiltration process. This overcomes the bottleneck of traditional melt infiltration methods for preparing molybdenum skeletons using powder sintering, which easily leads to closed voids, subsequent component segregation, and uneven microstructure. This lays the structural foundation for achieving high thermal conductivity and a low coefficient of thermal expansion. Finally, DC-assisted hot pressing sintering technology is employed. Under the combined effect of Joule heating and electric field effects, intense charge migration and mass transfer occur within the material, significantly reducing the plastic flow stress of the copper and molybdenum phases. Simultaneously, the current effectively promotes atomic diffusion and dynamic recrystallization at the interface, not only eliminating interface defects but also forming a high-strength metallurgical bond at the copper / molybdenum interface. This simultaneously achieves material densification and precise control of the interface microstructure. Through the coupling effect of multiple processes, a synergistic breakthrough was achieved in the thermal conductivity, heat deformation resistance and overall reliability of composite materials while ensuring interface integrity and high bonding strength. Attached Figure Description

[0017] Figure 1 The flowchart illustrates the preparation method of the copper / molybdenum copper / copper layered composite material provided by this invention.

[0018] Figure 2 This is a schematic diagram of the copper / molybdenum copper / copper layered composite material prepared by the method of the present invention.

[0019] Figure 3 This is a morphology diagram of the nickel plating layer obtained by chemical plating in Example 4 of the present invention.

[0020] Figure 4 This is the energy spectrum of the copper-molybdenum bonding interface in Example 5 of the present invention. Detailed Implementation

[0021] The following detailed description is provided in conjunction with specific implementation methods.

[0022] Example 1 The method for preparing the copper / molybdenum copper / copper layered composite material of the present invention is implemented according to the following steps: Step 1: A porous molybdenum framework is prepared using electron beam selective melting, specifically as follows: Step 1.1, 3D modeling Based on a pre-defined 3D interpenetrating double continuous topology, a 3D digital model of the molybdenum skeleton to be printed was constructed. Then, the 3D digital model of the molybdenum skeleton was imported into slicing software for slicing, with a slice thickness of 40 mm. ~80 The generated slice data is then imported into the electron beam printing equipment control system. The three-dimensional interpenetrating double continuous topology is a biomimetic microstructure with double continuous characteristics, specifically: a three-period minimal surface TPMS structure or a diamond lattice structure, etc. Step 1.2, spreading powder Dried spherical molybdenum powder with a particle size range of 45μm~105μm was added to a powder cylinder for preparation before electron beam selective melting and forming. The substrate in the forming chamber was preheated to a preset temperature using an electron beam, and the powder in the powder cylinder was spread onto the substrate using a scraper. The substrate was a molybdenum plate, and the vacuum degree of the forming chamber reached 10. -2 Helium is introduced at Pa, and the preheating temperature of the substrate is 1200℃~1400℃; Step 1.3, Print The powder is preheated using a defocused electron beam, and then the powder is selectively melted using a focused electron beam. After melting, the powder bed is kept warm using a defocused electron beam. Then the scanning direction is rotated by 90°, the substrate is lowered by one powder layer thickness, and the scanning is repeated until the porous molybdenum skeleton is manufactured. Among them, the preheating scanning current for preheating the powder using a defocused electron beam is 12mA~30mA, and the preheating time is 10s~20s; Selective melting of powder is performed using a focused electron beam, specifically: the melting electron beam current is 10mA~20mA, the melting electron beam scanning speed is 0.5m / s~3m / s, and the electron beam spot diameter is controlled to be 100μm~225μm for scanning; After melting, the electron beam current for heat preservation of the powder bed using a decoupling electron beam is 12mA~30mA, and the heat preservation time is 5s~15s.

[0023] Step 2: After pretreatment, the porous molybdenum skeleton prepared in Step 1 is surface modified by electroless nickel plating. Step 3: The porous molybdenum skeleton with nickel plating in Step 2 is infiltrated with oxygen-free copper blocks to obtain CPC infiltrated ingot billet. Step 4: The CPC melt-infiltrating ingot obtained in Step 3 is subjected to DC-assisted hot pressing sintering to obtain CPC layered composite material.

[0024] Example 2 The method for preparing the copper / molybdenum copper / copper layered composite material of the present invention is implemented according to the following steps: Step 1: A porous molybdenum framework is prepared using electron beam selective melting, specifically as follows: Step 1.1, 3D modeling Based on a pre-defined 3D interpenetrating double continuous topology, a 3D digital model of the molybdenum skeleton to be printed was constructed. Then, the 3D digital model of the molybdenum skeleton was imported into slicing software for slicing, with a slice thickness of 40 mm. ~80 The generated slice data is then imported into the electron beam printing equipment control system. The three-dimensional interpenetrating double continuous topology is a biomimetic microstructure with double continuous characteristics, specifically: a three-period minimal surface TPMS structure or a diamond lattice structure, etc. Step 1.2, spreading powder Dried spherical molybdenum powder with a particle size range of 45μm~105μm was added to a powder cylinder for preparation before electron beam selective melting and forming. The substrate in the forming chamber was preheated to a preset temperature using an electron beam, and the powder in the powder cylinder was spread onto the substrate using a scraper. The substrate was a molybdenum plate, and the vacuum degree of the forming chamber reached 10. -2 Helium is introduced at Pa, and the preheating temperature of the substrate is 1200℃~1400℃; Step 1.3, Print The powder is preheated using a defocused electron beam, and then the powder is selectively melted using a focused electron beam. After melting, the powder bed is kept warm using a defocused electron beam. Then the scanning direction is rotated by 90°, the substrate is lowered by one powder layer thickness, and the scanning is repeated until the porous molybdenum skeleton is manufactured. Among them, the preheating scanning current for preheating the powder using a defocused electron beam is 12mA~30mA, and the preheating time is 10s~20s; Selective melting of powder is performed using a focused electron beam, specifically: the melting electron beam current is 10mA~20mA, the melting electron beam scanning speed is 0.5m / s~3m / s, and the electron beam spot diameter is controlled to be 100μm~225μm for scanning; After melting, the electron beam current for heat preservation of the powder bed using a decoupling electron beam is 12mA~30mA, and the heat preservation time is 5s~15s.

[0025] Step 2: After pretreatment, the porous molybdenum skeleton prepared in Step 1 is surface modified by electroless nickel plating. The preprocessing specifically includes: After thoroughly washing the porous molybdenum skeleton in the pickling solution, it was rinsed repeatedly with alcohol until the surface of the porous molybdenum skeleton became neutral and then dried. The pickling solution consisted of 10%~13% nitric acid and 87%~90% deionized water. Electroless nickel plating uses an electroless nickel plating solution, which is prepared by dissolving the solutes in deionized water. The solutes and their concentrations are as follows: nickel sulfate hexahydrate 100g / L~150g / L, nickel chloride 10g / L~30g / L, sodium sulfate 150g / L~200g / L, and boric acid 20g / L~30g / L.

[0026] The electroless nickel plating process involves heating the electroless nickel plating solution to 80°C~90°C, immersing it in a pretreated porous molybdenum skeleton for 30min~60min to obtain a continuous and uniform nickel plating layer with a thickness of 3μm~10μm, and then removing the porous molybdenum skeleton, rinsing it with deionized water, and drying it.

[0027] Step 3: The porous molybdenum skeleton with nickel plating in Step 2 is infiltrated with oxygen-free copper blocks to obtain CPC infiltrated ingot billet. Step 4: The CPC melt-infiltrating ingot obtained in Step 3 is subjected to DC-assisted hot pressing sintering to obtain CPC layered composite material.

[0028] Example 3 The method for preparing the copper / molybdenum copper / copper layered composite material of the present invention is implemented according to the following steps: Step 1: A porous molybdenum framework is prepared using electron beam selective melting, specifically as follows: Step 1.1, 3D modeling Based on a pre-defined 3D interpenetrating double continuous topology, a 3D digital model of the molybdenum skeleton to be printed was constructed. Then, the 3D digital model of the molybdenum skeleton was imported into slicing software for slicing, with a slice thickness of 40 mm. ~80 The generated slice data is then imported into the control system of the electron beam printing equipment. The three-dimensional interpenetrating double continuous topology is a biomimetic microstructure with double continuous characteristics, specifically: a three-period minimal surface TPMS structure, a diamond lattice structure, or a biomimetic microstructure with double continuous characteristics. The core advantage of this structure lies in its dual-phase continuous and interconnected characteristics, which can construct a three-dimensional heat flow path with low tortuosity in the model, thereby greatly optimizing the electron phonon transmission efficiency and ensuring that heat can be efficiently conducted along the three-dimensional direction. Step 1.2, spreading powder Dried spherical molybdenum powder with a particle size range of 45μm~105μm was added to a powder cylinder for preparation before electron beam selective melting and forming. The substrate in the forming chamber was preheated to a preset temperature using an electron beam, and the powder in the powder cylinder was spread onto the substrate using a scraper. The substrate was a molybdenum plate, and the vacuum degree of the forming chamber reached 10. -2 Helium is introduced at Pa, and the preheating temperature of the substrate is 1200℃~1400℃; Step 1.3, Print The powder is preheated using a defocused electron beam, and then the powder is selectively melted using a focused electron beam. After melting, the powder bed is kept warm using a defocused electron beam. Then the scanning direction is rotated by 90°, the substrate is lowered by one powder layer thickness, and the scanning is repeated until the porous molybdenum skeleton is manufactured. Among them, the preheating scanning current for preheating the powder using a defocused electron beam is 12mA~30mA, and the preheating time is 10s~20s; Selective melting of powder is performed using a focused electron beam, specifically: the melting electron beam current is 10mA~20mA, the melting electron beam scanning speed is 0.5m / s~3m / s, and the electron beam spot diameter is controlled to be 100μm~225μm for scanning; After melting, the electron beam current of the powder bed is 12mA~30mA and the holding time is 5s~15s. By precisely controlling the energy input, powder splashing and spheroidization are reduced, thereby directly improving the surface quality of the melt channel. By rotating 90° layer by layer, the step effect accumulated layer by layer is dispersed, and the surface of the current layer is refined twice, which can significantly reduce the surface roughness of the molybdenum skeleton.

[0029] Step 2: After pretreatment, the porous molybdenum skeleton prepared in Step 1 is surface modified by electroless nickel plating. The preprocessing specifically includes: After thoroughly washing the porous molybdenum skeleton in the pickling solution, it was rinsed repeatedly with alcohol until the surface of the porous molybdenum skeleton became neutral and then dried. The pickling solution consisted of 10%~13% nitric acid and 87%~90% deionized water. Electroless nickel plating uses an electroless nickel plating solution, which is prepared by dissolving the solutes in deionized water. The solutes and their concentrations are as follows: nickel sulfate hexahydrate 100g / L~150g / L, nickel chloride 10g / L~30g / L, sodium sulfate 150g / L~200g / L, and boric acid 20g / L~30g / L.

[0030] The electroless nickel plating process involves heating the electroless nickel plating solution to 80°C~90°C, immersing it in a pretreated porous molybdenum skeleton for 30min~60min to obtain a continuous and uniform nickel plating layer with a thickness of 3μm~10μm, and then removing the porous molybdenum skeleton, rinsing it with deionized water, and drying it.

[0031] Step 3: The porous molybdenum skeleton with nickel plating obtained in Step 2 is melt-infiltrated with oxygen-free copper blocks to obtain CPC melt-infiltrated ingot blanks. Specifically, a graphite strip is placed at the bottom of a graphite crucible, the porous molybdenum skeleton with nickel plating obtained in Step 2 is placed on the graphite strip, and an oxygen-free copper block of appropriate size is placed on the porous molybdenum skeleton for melt-infiltration to obtain CPC melt-infiltrated ingot blanks. The melting and infiltration process parameters are: temperature 1200℃~1500℃, holding time 3h~5h, and finally cooling to room temperature with the furnace, with hydrogen as the protective atmosphere.

[0032] Step 4: The CPC melt-infiltrated ingot obtained in Step 3 is subjected to DC-assisted hot pressing sintering to obtain CPC layered composite material. The process parameters for DC-assisted hot pressing sintering are: temperature 600℃~950℃, pressure 20MPa~40MPa, holding time 10min~30min, and then cooled to room temperature in a vacuum furnace to obtain CPC layered composite material.

[0033] This invention first uses electron beam melting technology to design a three-dimensional structure and prepare a porous molybdenum framework with a precise topological structure. To address the inherent poor wettability of the molybdenum-copper interface, the framework is chemically plated with nickel to form a high-performance metallurgical transition layer. This allows for efficient filling of the copper melt in the subsequent infiltration process, forming a complete three-dimensional interpenetrating double continuous structure of molybdenum and copper. This ensures that the two components are tightly bonded throughout the three-dimensional space, thereby achieving ideal basic interface strength. Finally, the composite ingot is subjected to DC-assisted hot pressing sintering. This step, based on the strong interface formed in the previous step, utilizes the synergistic effect of electric field and planar constraint to precisely control the interface structure and promote densification.

[0034] Example 4 Based on Example 3, spherical molybdenum (Mo) powder with a particle size range of 45 μm to 105 μm was dried. A three-dimensional porous molybdenum framework digital model was created based on the Gyroid (G-surface) unit structure, and the model was sliced ​​with a slice thickness of 65 μm. The slice model was then imported into the control system of the electron beam selective melting (EBSM) equipment. The dried molybdenum powder was loaded into the powder supply chamber of the electron beam equipment and buried under the substrate. The substrate and scraper were installed and leveled to ensure good contact between the thermocouple and the substrate, and the chamber door was closed. The forming chamber was evacuated to 2 × 10⁻⁶. -2 After Pa, helium was introduced as a protective atmosphere. Three minutes later, electron beam alignment was performed to ensure the electron beam was at the geometric center of the substrate, and the current was gradually adjusted to stabilize the gate voltage. The substrate was preheated to 1000°C by electron beam scanning, and then the first layer of powder was deposited using a doctor blade. Electron beam preheating was performed on the powder using the following parameters: beam current 12mA, time 20s. Selective melting was then performed with the following main process parameters: melting beam current 10mA, scanning speed 2.5m / s, beam spot diameter 150μm. A scanning strategy with 90° interlayer rotation was used to optimize the grain structure and stress distribution. After each layer was formed, the substrate was lowered by one layer thickness, and electron beam thermal compensation scanning was performed before continuing powder deposition for the next layer. After forming, the porous molybdenum framework was slowly cooled to room temperature in the furnace under helium protection. The molybdenum skeleton was immersed in a pickling solution prepared with 10% nitric acid and 90% deionized water for cleaning, then rinsed with alcohol and dried. It was then immersed in an 80°C electroless nickel plating solution for 60 minutes to obtain a uniform nickel plating layer. The molybdenum skeleton was then removed, cleaned, and dried. The morphology of the nickel-plated layer is as follows: Figure 3As shown, the coating is uniform and smooth, with a thickness of approximately 6.5 μm. The cleaned molybdenum skeleton was placed on a graphite strip at the bottom of a graphite mold, and an oxygen-free copper block was placed on top. Melt infiltration sintering was then performed in a hydrogen atmosphere with the following process parameters: 1300℃ for 4 hours. Subsequently, the obtained melt-infiltrated ingot was subjected to DC-assisted hot pressing sintering under the following conditions: temperature 700℃, holding time 30 minutes, and pressure 30 MPa. Finally, a copper / molybdenum / copper / copper layered composite material with a complete structure and excellent interfacial bonding was obtained.

[0035] Example 5 Based on Example 3, spherical molybdenum (Mo) powder with a particle size range of 45 μm to 105 μm was dried. A three-dimensional porous molybdenum framework digital model was created based on the Schwarz P unit structure, and the model was sliced ​​with a slice thickness of 40 μm. The sliced ​​model was then imported into the control system of the EBSM equipment. The dried molybdenum powder was loaded into the powder supply chamber of the electron beam equipment and buried under the substrate. The substrate and scraper were installed and leveled to ensure good contact between the thermocouple and the substrate, and the chamber door was closed. The forming chamber was evacuated to 5 × 10⁻⁶. -2 After Pa, helium was introduced as a protective atmosphere. Three minutes later, electron beam alignment was performed to ensure the electron beam was at the geometric center of the substrate, and the current was gradually adjusted to stabilize the gate voltage. The substrate was preheated to 1200°C by electron beam scanning, and then the first layer of powder was deposited using a doctor blade. The powder was preheated in a specific area using an electron beam with the following parameters: beam current 15mA, time 15s. Selective melting was then performed with the following main process parameters: melting beam current 15mA, scanning speed 3m / s, beam spot diameter 100μm. A scanning strategy with 90° interlayer rotation was used to optimize the grain structure and stress distribution. After each layer was formed, the substrate was lowered by one layer thickness, and an electron beam thermal compensation scan was performed before continuing powder deposition for the next layer. After forming, the porous molybdenum framework was slowly cooled to room temperature in the furnace under helium protection. The molybdenum skeleton was cleaned by immersing it in an acid pickling solution prepared with 13% nitric acid and 87% deionized water, then rinsed with alcohol and dried. It was then immersed in an 85°C electroless nickel plating solution for 45 minutes to obtain a uniform nickel plating layer. The molybdenum skeleton was then removed, cleaned, and dried. The cleaned molybdenum skeleton was placed on a graphite strip at the bottom of a graphite mold, and an oxygen-free copper block was placed on top. Melt infiltration sintering was performed in a hydrogen atmosphere with the following process parameters: 1200°C for 5 hours. Subsequently, the obtained melt-infiltrated ingot was subjected to DC-assisted hot pressing sintering under the following process conditions: temperature 950°C, holding time 10 minutes, and pressure 20 MPa. Finally, a copper / molybdenum / copper / copper layered composite material with a complete structure and excellent interfacial bonding was obtained. Its interface is as follows... Figure 4 As shown, from Figure 4 It can be seen that the interface is well bonded, and the interface bonding mechanism has changed from mechanical interlocking to metallurgical bonding.

[0036] Example 6 Based on Example 3, spherical molybdenum (Mo) powder with a particle size range of 45 μm to 105 μm was dried. A three-dimensional porous molybdenum framework digital model was created based on a biomimetic structure, and it was sliced ​​with a slice thickness of 70 μm. The slice model was then imported into the control system of the EBSM equipment. The dried molybdenum powder was loaded into the powder supply chamber of the electron beam equipment and buried under the substrate. The substrate and scraper were installed and leveled to ensure good contact between the thermocouple and the substrate, and the chamber door was closed. The forming chamber was evacuated to 3 × 10⁻⁶. -2 After Pa, helium was introduced as a protective atmosphere. Three minutes later, electron beam alignment was performed to ensure the electron beam was at the geometric center of the substrate, and the current was gradually adjusted to stabilize the gate voltage. The substrate was preheated to 1400°C by electron beam scanning, and then the first layer of powder was deposited using a doctor blade. Electron beam preheating was performed on the powder using the following parameters: beam current 30mA, time 10s. Selective melting was then performed, with the following main process parameters: melting beam current 20mA, scanning speed 2m / s, beam spot diameter 200μm. A 90° interlayer rotation scanning strategy was used to optimize the grain structure and stress distribution. After each layer was formed, the substrate was lowered by one layer thickness, and electron beam thermal compensation scanning was performed before continuing powder deposition for the next layer. After forming, the porous molybdenum framework was slowly cooled to room temperature in the furnace under helium protection. The molybdenum skeleton was cleaned by immersing it in an acid pickling solution prepared with 10% nitric acid and 90% deionized water, then rinsed with alcohol and dried. It was then immersed in a 90°C electroless nickel plating solution for 30 minutes to obtain a uniform nickel plating layer. The molybdenum skeleton was then removed, cleaned, and dried. The cleaned molybdenum skeleton was placed on a graphite strip at the bottom of a graphite mold, and an oxygen-free copper block was placed on top. Melt infiltration sintering was performed in a hydrogen atmosphere with the following process parameters: 1500°C for 3 hours. Subsequently, the obtained melt-infiltrated ingot was subjected to DC-assisted hot pressing sintering under the following conditions: 600°C, 25 minutes, and 40 MPa. Finally, a copper / molybdenum / copper / copper layered composite material with a complete structure and excellent interfacial bonding was obtained.

Claims

1. A method for producing a copper / molybdenum copper / copper layered composite material, characterized by, The method is implemented according to the following steps: Step 1: a porous molybdenum framework is prepared by electron beam selective melting; Step 2: the porous molybdenum framework prepared in step 1 is pretreated and then surface modified by electroless nickel plating; Step 3: the porous molybdenum framework with a surface plated with nickel in step 2 is infiltrated with oxygen-free copper blocks to obtain a CPC infiltrated ingot; Step 4: the CPC infiltrated ingot obtained in step 3 is subjected to direct current assisted hot-pressing sintering to obtain a CPC layered composite material.

2. The method for preparing copper / molybdenum copper / copper layered composite material according to claim 1, characterized in that, The step 1 is specifically as follows: Step 1.1: three-dimensional modeling Based on a preset three-dimensional interpenetrating bicontinuous topological structure, a three-dimensional digital model of the molybdenum framework to be printed is constructed, and then the three-dimensional digital model of the molybdenum framework is imported into a slicing software for slicing, and the generated slicing data is imported into an electron beam printing equipment control system; Step 1.2: powder laying After the dried spherical molybdenum powder is added to a powder cylinder, the substrate in the forming bin is preheated to a preset temperature by an electron beam, and the powder in the powder cylinder is laid on the substrate by a scraper; Step 1.3: printing The powder is preheated by a defocused electron beam, the powder is selectively melted by a focused electron beam, the powder bed is then kept warm by a defocused electron beam after melting, the scanning direction is then rotated by 90°, the substrate is lowered by one powder laying thickness, and the scanning is repeated until the porous molybdenum framework is completed.

3. The method for preparing copper / molybdenum copper / copper layered composite material according to claim 2, characterized in that, The three-dimensional interpenetrating bicontinuous topological structure in step 1.1 is a biomimetic microstructure with bicontinuous characteristics, specifically: a three-periodic minimal surface (TPMS) structure or a diamond lattice structure.

4. The method for preparing copper / molybdenum copper / copper layered composite material according to claim 2, characterized in that, The thickness of the sectioning in step 1.1 is 40 ~80 .

5. The method for preparing copper / molybdenum copper / copper layered composite material according to claim 2, characterized in that, The particle size of the spherical molybdenum powder in step 1.2 is 45-105 μm, the substrate is a molybdenum plate, and the vacuum degree of the forming chamber reaches 10 -2 Pa -3 Pa, helium is filled in, and the preheating temperature of the substrate is 1200-1400℃.

6. The method for preparing copper / molybdenum copper / copper layered composite material according to claim 2, characterized in that, In step 1.3, the scanning current for preheating the powder by a defocused electron beam is 12mA-30mA, and the preheating time is 10s-20s; The powder is selectively melted by a focused electron beam, specifically: the melting electron beam current is 10mA-20mA, the melting electron beam scanning speed is 0.5m / s-3m / s, and the scanning is controlled by an electron beam spot diameter of 100μm-225μm; After melting, the powder bed is kept warm by a defocused electron beam with an electron beam current of 12mA-30mA for 5s-15s.

7. The method for preparing copper / molybdenum copper / copper layered composite material according to claim 1, characterized in that, The pretreatment in step 2 is specifically as follows: The porous molybdenum framework is washed thoroughly in an acid pickling solution and then cleaned multiple times with alcohol until the surface of the porous molybdenum framework becomes neutral, and then dried, the acid pickling solution is composed of 10%-13% nitric acid and 87%-90% deionized water; In step 2, electroless nickel plating is performed using an electroless nickel plating solution, the electroless nickel plating solution is prepared by dissolving solutes into a solvent, the solvent is deionized water, the solutes and their concentrations are as follows: 100g / L-150g / L of nickel sulfate hexahydrate, 10g / L-30g / L of nickel chloride, 150g / L-200g / L of sodium sulfate, and 20g / L-30g / L of boric acid.

8. The method for preparing copper / molybdenum copper / copper layered composite material according to claim 1, characterized in that, In step 2, the electroless nickel plating is specifically as follows: the electroless nickel plating solution is heated to 80℃-90℃, the pretreated porous molybdenum framework is immersed in the solution for 30min-60min to obtain a continuous and uniform nickel plating layer with a thickness of 3μm-10μm, and then the porous molybdenum framework is taken out, cleaned with deionized water, and dried.

9. The method for preparing copper / molybdenum copper / copper layered composite material according to claim 1, characterized in that, The step 3 is specifically: placing a graphite strip at the bottom of a graphite crucible, placing the porous molybdenum skeleton plated with nickel obtained in the step 2 on the graphite strip, and placing an oxygen-free copper block with a proper size on the porous molybdenum skeleton to obtain a CPC infiltrated ingot blank by means of melt infiltration; The melt infiltration process parameters are: a temperature of 1200-1500 DEG C, a holding time of 3-5 h, and finally cooling to room temperature with the furnace, and a protective atmosphere of hydrogen.

10. The method for preparing copper / molybdenum copper / copper layered composite material according to claim 1, characterized in that, The step 4 is specifically: carrying out direct current assisted hot-press sintering on the CPC infiltrated ingot blank obtained in the step 3, and the direct current assisted hot-press sintering process parameters are: a temperature of 600-950 DEG C, a pressure of 20-40 MPa, a holding time of 10-30 min, and cooling to room temperature with the furnace under vacuum, so as to obtain a CPC layered composite material.

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