Metal material for processing porous micro-channel

Abstract

The invention relates to the technical field of metal materials, and discloses a porous microchannel machining metal material which comprises the following components in percentage by mass: 0.5%-3.0% of aluminum, 2.0%-5.0% of nickel, 0.2%-1.0% of titanium, 0.1%-0.5% of zirconium and the balance of metal. 1.0%-4.0% of a silicon carbide or aluminum nitride reinforcing phase; 3%-10% of a composite pore-forming agent; 0.03%-0.1% of rare earth elements and 0.05%-0.2% of zirconium oxide; 1.0%-3.0% of chromium and 0.01%-0.1% of carbon; and the balance of copper matrix. Through unique component design and a composite preparation process, good balance between high heat conductivity and high strength of the porous micro-channel metal material is achieved, the tensile strength at room temperature is enhanced, the elongation percentage is 18%, the performance is still kept excellent after 500 times of heat cycles, improvement of the performance is mainly benefited from the synergistic effect of a copper matrix and micro-alloy elements, and the performance of the porous micro-channel metal material is improved. And the pore structure is finely regulated and controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, in particular to a metal material for processing porous microchannels. Background Art

[0002] With the rapid development of modern industrial technology, the demand for high-efficiency heat exchange and heat dissipation materials in various fields is becoming increasingly urgent. In some high-tech fields, porous microchannel metal materials are widely used due to their unique heat transfer and flow characteristics. Porous microchannel metal materials are a type of metal-based composite materials with a three-dimensional through-pore structure and precise flow channel design. Their core feature is the synergy between controllable pores and micron-level channels to achieve efficient heat transfer, fluid distribution and structural function integration.

[0003] However, the performance of traditional porous materials still has defects. Among them, conventional pore-forming agents (such as single ammonium bicarbonate or polymers) have low pore connectivity and large size deviation due to problems such as wide particle size distribution and decomposition residue, which significantly reduces heat transfer efficiency. It makes it difficult to balance the thermal conductivity and strength of traditional copper-based porous materials. The mechanical properties and thermal stability are insufficient in high-temperature environments, and some materials have poor corrosion resistance and thermal fatigue resistance. These problems seriously restrict the performance improvement and reliability of related equipment. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a metal material for porous microchannel processing, which solves the problem that traditional copper-based porous materials are difficult to balance thermal conductivity and strength, and have insufficient mechanical properties and thermal stability in high-temperature environments.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] A metal material for porous microchannel processing comprises the following components in percentage by mass: 0.5%-3.0% aluminum, 2.0%-5.0% nickel, 0.2%-1.0% titanium, and 0.1%-0.5% zirconium; 1.0%-4.0% silicon carbide or aluminum nitride reinforcement phase; 3%-10% composite pore-forming agent with a particle size of 5-30 μm, the composite pore-forming agent being composed of ammonium bicarbonate and polymethyl methacrylate microspheres in a mass ratio of 1:1-3:1; 0.03%-0.1% rare earth element, the rare earth element being selected from at least one of lanthanum, cerium, and yttrium; 0.05%-0.2% zirconium oxide; 1.0%-3.0% chromium, 0.01%-0.1% carbon, and 0.01%-0.05% nitrogen; and a copper matrix: the remainder.

[0007] By adopting the above technical solution: through unique composition design and composite preparation process, a good balance between high thermal conductivity and high strength of porous microchannel metal materials is achieved. In the application of heat dissipation components in electronic equipment, the thermal conductivity reaches 380W / (m·K), which is 15% higher than that of traditional materials. The room temperature tensile strength reaches 320MPa and the elongation is 18%. The performance remains excellent after 500 thermal cycles. This performance improvement is mainly due to the synergistic effect of the copper matrix and microalloying elements, as well as the fine control of the pore structure.

[0008] Preferably, the grain size of the copper matrix is 1-5 μm, the grain orientation deviation is less than 15°, the porosity is controlled at 15%-35%, and the pore connectivity is greater than 90%.

[0009] Preferably, a method for preparing a porous microchannel processing metal material is used for the porous microchannel processing metal material, and the method comprises the following steps:

[0010] S1. Raw material pretreatment: The metal powder is subjected to three-dimensional vortex mixing under argon protection and ultrasonic cleaning is performed simultaneously. The cleaning time is 10-30 minutes and the temperature is 20-40°C;

[0011] S2. Vacuum melting: melting the copper-based alloy under a vacuum degree of 1-10 Pa at a temperature of 1200-1400°C for 1-2 hours;

[0012] S3, atomization powder making: preparing pre-alloyed powder with a particle size of 10-50 μm by gas atomization of the molten alloy;

[0013] S4. Preparation of composite powder: Mix the pre-alloyed powder with the reinforcement phase and the pore-forming agent at a low temperature of -10-10°C for 30-120 minutes;

[0014] S5. Molding process: cold isostatic pressing and laser cladding composite molding of the composite powder;

[0015] S6. Sintering and heat treatment: sintering and quenching and tempering the formed body in stages;

[0016] S7, Microchannel processing: Laser-electrolysis composite process is used to process microchannel structure;

[0017] S8, post-processing: pickling, passivation and gradient cooling treatment of the workpiece;

[0018] S9. Quality inspection: X-ray tomography is used to verify that the pore connectivity is greater than 90%, and electron backscatter diffraction is used to confirm that the grain orientation deviation is less than 15°.

[0019] Preferably, the forming process of S5 specifically includes:

[0020] Cold isostatic pressing preforming: preparing green bodies at a pressure of 150-300 MPa;

[0021] Selective laser melting: laser power 200-400W, scanning speed 800-1500mm / s, layer thickness 20-50μm to build three-dimensional structures;

[0022] Rolling strengthening: The formed parts are subjected to multiple rolling with a deformation of 30%-50%, and the rolling temperature is controlled at 100-200℃.

[0023] Preferably, the sintering and heat treatment of S6 includes:

[0024] Degreasing stage: heating at 2-5℃ / min to 300-400℃ and keeping at this temperature for 1-3 hours to decompose the pore-forming agent;

[0025] Vacuum sintering: heat to 1200-1350℃ at 10-3-10-2Pa vacuum and keep at this temperature for 3-6 hours;

[0026] Quenching and tempering: After oil quenching at 700-900℃, temper at 100-300℃ for 0.5-2 hours, and air cool to room temperature after tempering.

[0027] Preferably, the following conditions are applied simultaneously during the vacuum sintering stage:

[0028] 0.5-2T pulsed magnetic field, frequency 10-50Hz, magnetic field direction is 45°-90° with the direction of gravity;

[0029] Nitrogen-helium mixed shielding gas, nitrogen accounts for 60%-80%, flow rate is 5-15L / min, oxygen content is ≤50ppm.

[0030] Preferably, the microchannel processing of S7 includes:

[0031] Laser rough processing: Use 1064nm fiber laser with peak power of 1-5kW and pulse width of 10-100ns to form the channel prototype, with a focused spot diameter of 20-50μm;

[0032] Electrolytic finishing: Use 10%-30% nitric acid electrolyte, voltage 5-15V, current density 20-50A / cm 2 , inter-pole distance 0.1-0.5mm;

[0033] Circular processing: 2-4 times of laser and electrolysis alternating processing are carried out, with the laser processing depth decreasing by 20%-50% each time and the electrolysis time increasing by 30%-100%.

[0034] Preferably, the post-processing of S8 includes:

[0035] Pickling passivation: ultrasonic treatment in 10%-25% hydrofluoric acid solution for 10-30 minutes, frequency 40-100kHz, ultrasonic power 50-200W;

[0036] Gradient cooling: cool to 150-200℃ at 5-10℃ / min, keep at this temperature for 0.5-1 hour, then cool to room temperature at 1-3℃ / min;

[0037] Oxidation treatment: Surface passivation is performed at 200-400°C and 10%-30% oxygen concentration for 1-3 hours, with nitrogen being introduced as the carrier gas.

[0038] Preferably, the quality inspection of S9 further includes:

[0039] The pitting potential was measured in 3.5% sodium chloride solution using a three-electrode system. The working electrode consisted of the material to be tested, the reference electrode was a saturated calomel electrode, and the auxiliary electrode was a platinum electrode. The potential scan rate was 1 mV / s.

[0040] The surface roughness was detected using a laser confocal microscope with a spot diameter of ≤5 μm and a scanning step length of 0.1 μm.

[0041] Preferably, a porous microchannel processing metal material is used to manufacture electronic equipment heat dissipation components, aerospace heat exchangers or automobile engine cooling systems.

[0042] The present invention provides a metal material for porous microchannel processing. It has the following beneficial effects:

[0043] 1. Through unique component design and composite preparation technology, this invention achieves an excellent balance between high thermal conductivity and high strength in porous microchannel metal materials. In applications such as heat dissipation components in electronic equipment, the thermal conductivity reaches 380 W / (m·K), a 15% improvement over traditional materials. The room-temperature tensile strength reaches 320 MPa, and the elongation is 18%. The performance remains excellent after 500 thermal cycles. This performance improvement is primarily due to the synergistic effect of the copper matrix and microalloying elements, as well as the precise control of the pore structure.

[0044] 2. The present invention effectively solves the problems of component segregation and uneven porosity in the preparation of porous microchannel materials by adopting a multi-process integration method including vacuum melting, atomization powder making, composite powder processing, cold isostatic pressing and laser cladding forming. By controlling the pulsed magnetic field and gas environment during the sintering stage, the porosity is stably controlled at 30%±2%, the connectivity reaches 92%±1%, and the component uniformity is improved by 30%, providing a reliable technical path for the industrial production of high-performance porous microchannel materials.

[0045] 3. The material of the present invention can adapt to various complex working conditions such as electronic equipment, aerospace, and automobile engines, and shows good environmental resistance. After 500 hours of salt spray test, the corrosion depth of the material is only 14μm, which is much lower than the 32μm of the control group; after 1000 thermal cycles, the pore collapse rate is less than 3%. Through the synergistic effect of rare earth elements, zirconium oxide and composite pore-forming agents, the special surface and interface structure formed significantly improves the material's corrosion resistance and thermal fatigue resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention is a flow chart of a method for preparing a metal material for porous microchannel processing. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0048] An embodiment of the present invention provides a metal material for porous microchannel processing, comprising the following components in percentage by mass: 0.5%-3.0% aluminum, 2.0%-5.0% nickel, 0.2%-1.0% titanium, and 0.1%-0.5% zirconium; 1.0%-4.0% silicon carbide or aluminum nitride reinforcement phase; 3%-10% composite pore-forming agent with a particle size of 5-30 μm, the composite pore-forming agent being composed of ammonium bicarbonate and polymethyl methacrylate microspheres in a mass ratio of 1:1-3:1; 0.03%-0.1% rare earth element, wherein the rare earth element is selected from at least one of lanthanum, cerium, and yttrium; 0.05%-0.2% zirconium oxide; 1.0%-3.0% chromium, 0.01%-0.1% carbon, and 0.01%-0.05% nitrogen; and a copper matrix: the remainder.

[0049] Specifically, the copper matrix is the main component, which provides the basic electrical conductivity and thermal conductivity of the material, and also gives the material good processing properties, so that it can be manufactured into complex microchannel structures through various molding processes; aluminum can refine the grains of the copper matrix, thereby improving the strength and hardness of the material; the addition of nickel can significantly improve the strength and toughness of the material and improve its fatigue resistance; titanium is a strong refiner, which can refine the grains, improve the strength and hardness of the material, and improve the wear resistance and corrosion resistance of the material; zirconium can improve the strength and hardness of the material, improve its wear resistance and corrosion resistance; silicon carbide or aluminum nitride as a reinforcing phase can significantly improve the hardness and The composite pore-forming agent is composed of ammonium bicarbonate and polymethyl methacrylate microspheres, which are used to form a uniform porous structure inside the material; rare earth elements can refine the grains, improve the strength and hardness of the material, and improve the wear resistance and corrosion resistance of the material; zirconium oxide can improve the hardness and wear resistance of the material, improve the thermal conductivity and high-temperature stability of the material; chromium can improve the strength and hardness of the material, improve its wear resistance and corrosion resistance; carbon and nitrogen can improve the strength and hardness of the material, improve its wear resistance, and they can form carbides and nitrides with the base metal to further enhance the hardness and wear resistance of the material.

[0050] The grain size of the copper matrix is 1-5 μm, the grain orientation deviation is less than 15°, the porosity is controlled at 15%-35%, and the pore connectivity is greater than 90%.

[0051] Specifically, the fine-grained structure with a grain size of 1-5 μm can significantly improve the strength of the material. The fine grains not only improve the strength of the material, but also improve its toughness. In the fine-grained structure, cracks are difficult to expand because the grain boundaries can disperse the tip stress of the crack, thereby delaying the expansion of the crack; materials with an orientation deviation of less than 15° show better performance during processing. In processes such as cold isostatic pressing and laser cladding forming, consistent orientation can reduce the residual stress generated during processing and improve the processing accuracy and surface quality of the material; the porous structure with a porosity controlled at 15%-35% can significantly optimize the heat exchange efficiency of the material. The porous structure increases the contact area between the fluid and the solid, thereby improving the heat transfer efficiency.

[0052] Please see the attached Figure 1 A method for preparing a porous microchannel processing metal material, which is used for the above-mentioned porous microchannel processing metal material, comprises the following steps:

[0053] S1. Raw material pretreatment: The metal powder is subjected to three-dimensional vortex mixing under argon protection and ultrasonic cleaning is performed simultaneously. The cleaning time is 10-30 minutes and the temperature is 20-40°C;

[0054] S2. Vacuum melting: melting the copper-based alloy under a vacuum degree of 1-10 Pa at a temperature of 1200-1400°C for 1-2 hours;

[0055] S3, atomization powder making: preparing pre-alloyed powder with a particle size of 10-50 μm by gas atomization of the molten alloy;

[0056] S4. Preparation of composite powder: Mix the pre-alloyed powder with the reinforcement phase and the pore-forming agent at a low temperature of -10-10°C for 30-120 minutes;

[0057] S5. Molding process: cold isostatic pressing and laser cladding composite molding of the composite powder;

[0058] S6. Sintering and heat treatment: sintering and quenching and tempering the formed body in stages;

[0059] S7, Microchannel processing: Laser-electrolysis composite process is used to process microchannel structure;

[0060] S8, post-processing: pickling, passivation and gradient cooling treatment of the workpiece;

[0061] S9. Quality inspection: X-ray tomography is used to verify that the pore connectivity is greater than 90%, and electron backscatter diffraction is used to confirm that the grain orientation deviation is less than 15°.

[0062] Please see the attached Figure 1 , S5 molding process specifically includes:

[0063] Cold isostatic pressing preforming: preparing green bodies at a pressure of 150-300 MPa;

[0064] Selective laser melting: laser power 200-400W, scanning speed 800-1500mm / s, layer thickness 20-50μm to build three-dimensional structures;

[0065] Rolling strengthening: The formed parts are subjected to multiple rolling with a deformation of 30%-50%, and the rolling temperature is controlled at 100-200℃.

[0066] Specifically, cold isostatic pressing preforming allows the powder to be initially compacted and formed, selective laser melting can achieve high-precision forming of complex shapes, and rolling strengthening can improve the density and strength of the material.

[0067] Please see the attached Figure 1 , S6 sintering and heat treatment include:

[0068] Degreasing stage: heating at 2-5℃ / min to 300-400℃ and keeping at this temperature for 1-3 hours to decompose the pore-forming agent;

[0069] Vacuum sintering: heat to 1200-1350℃ at 10-3-10-2Pa vacuum and keep at this temperature for 3-6 hours;

[0070] Quenching and tempering: After oil quenching at 700-900℃, temper at 100-300℃ for 0.5-2 hours, and air cool to room temperature after tempering.

[0071] Specifically, the degreasing stage can fully decompose and remove the pore-forming agent, avoiding the adverse effects of residual pore-forming agent on the subsequent sintering process and material properties; vacuum sintering can fully densify the material at high temperature, promote the diffusion and bonding between powder particles, and improve the strength and hardness of the material; quenching and tempering can eliminate the internal stress generated during the quenching process, improve the toughness and fatigue resistance of the material; finally, air cooling to room temperature stabilizes the material structure and obtains good comprehensive mechanical properties.

[0072] Please see the attached Figure 1 , the following conditions are applied simultaneously during the vacuum sintering stage:

[0073] 0.5-2T pulsed magnetic field, frequency 10-50Hz, magnetic field direction is 45°-90° with the direction of gravity;

[0074] Nitrogen-helium mixed shielding gas, nitrogen accounts for 60%-80%, flow rate is 5-15L / min, oxygen content is ≤50ppm.

[0075] Specifically, a pulsed magnetic field of 0.5-2T is applied, and the frequency is controlled at 10-50Hz. This pulsed magnetic field can break the electrostatic repulsion between powder particles, making the particles more evenly distributed during the sintering process, which helps to improve the density of the material; the direction of the magnetic field is at an angle of 45°-90° to the direction of gravity, which helps to reduce the pores and defects inside the material during the sintering process, while enhancing the bonding force between particles, thereby improving the overall strength and hardness of the material; the nitrogen-helium mixed gas can provide a stable protective atmosphere for the sintering process, effectively preventing material oxidation.

[0076] Please see the attached Figure 1 , S7's microchannel processing includes:

[0077] Laser rough processing: Use 1064nm fiber laser with peak power of 1-5kW and pulse width of 10-100ns to form the channel prototype, with a focused spot diameter of 20-50μm;

[0078] Electrolytic finishing: Use 10%-30% nitric acid electrolyte, voltage 5-15V, current density 20-50A / cm 2 , inter-pole distance 0.1-0.5mm;

[0079] Circular processing: 2-4 times of laser and electrolysis alternating processing are carried out, with the laser processing depth decreasing by 20%-50% each time and the electrolysis time increasing by 30%-100%.

[0080] Specifically, laser roughing can form the prototype of a microchannel on the surface of the material, providing the basic structure for subsequent finishing. Laser processing uses a high-energy-density laser beam to partially melt or vaporize the material through instantaneous high temperature, thereby forming the desired microchannel shape on the material surface. The electrolytic finishing process uses electrochemical reactions to finely trim the surface of the microchannel after laser processing. The electrolysis removes burrs, residues, and irregularities on the microchannel surface, making the inner wall of the microchannel smoother and flatter, and improving the quality and precision of the microchannel. The cyclic processing method can gradually optimize the shape and size of the microchannel, ensuring the precision and quality of the microchannel.

[0081] Please see the attached Figure 1 , S8 post-processing includes:

[0082] Pickling passivation: ultrasonic treatment in 10%-25% hydrofluoric acid solution for 10-30 minutes, frequency 40-100kHz, ultrasonic power 50-200W;

[0083] Gradient cooling: cool to 150-200℃ at 5-10℃ / min, keep at this temperature for 0.5-1 hour, then cool to room temperature at 1-3℃ / min;

[0084] Oxidation treatment: Surface passivation is performed at 200-400°C and 10%-30% oxygen concentration for 1-3 hours, with nitrogen being introduced as the carrier gas.

[0085] Specifically, the role of pickling passivation is to remove the oxide scale, residues and surface impurities generated during the processing, and at the same time form a dense passivation film on the surface of the material; the purpose of gradient cooling is to reduce the residual stress inside the material and avoid the concentration of thermal stress caused by rapid cooling, thereby improving the dimensional stability and mechanical properties of the material. The slow cooling process can gradually release the thermal stress inside the material and reduce cracks and deformation caused by excessive temperature gradients; the purpose of oxidation treatment is to form a uniform oxide film on the surface of the material, further improving the corrosion resistance and oxidation resistance of the material. By controlling the oxygen concentration and temperature, the thickness and composition of the oxide film can be precisely controlled. Nitrogen is used as a carrier gas to ensure that the oxidation process is carried out in a stable atmosphere to avoid the influence of other impurity gases on the oxide film.

[0086] Please see the attached Figure 1 , S9's quality inspection also includes:

[0087] The pitting potential was measured in 3.5% sodium chloride solution using a three-electrode system. The working electrode consisted of the material to be tested, the reference electrode was a saturated calomel electrode, and the auxiliary electrode was a platinum electrode. The potential scan rate was 1 mV / s.

[0088] The surface roughness was detected using a laser confocal microscope with a spot diameter of ≤5 μm and a scanning step length of 0.1 μm.

[0089] Specifically, by measuring the pitting potential, the corrosion resistance of the material in a specific environment can be evaluated. The higher the pitting potential, the better the pitting resistance of the material. This detection method can effectively predict the corrosion resistance of the material in actual use, especially in environments containing chloride ions, such as seawater, salt spray, etc.; at the same time, it can ensure the consistency and stability of the material during the production process. By comparing the pitting potential of different batches of materials, quality problems in the production process can be discovered in time, so that adjustments and improvements can be made; laser confocal microscopy can provide high-resolution surface morphology images and accurately measure the surface roughness and microstructure. By detecting the surface roughness, the quality control of the material during the processing process can be evaluated. The lower the surface roughness, the better the surface quality of the material, which can reduce fluid flow resistance and improve heat exchange efficiency, and also help to improve the corrosion resistance of the material.

[0090] The invention discloses an application of a metal material for porous microchannel processing, which is used to manufacture heat dissipation components of electronic equipment, aerospace heat exchangers or automobile engine cooling systems.

[0091] Specifically, the porous microchannel structure significantly increases the specific surface area of the material, allowing heat to be transferred more quickly from the heat-generating components of the electronic device to the surrounding environment. The high porosity and good pore connectivity further optimize the heat conduction path and improve the heat dissipation efficiency, thereby effectively reducing the internal temperature of the electronic device, extending the service life of the equipment, reducing the failure rate caused by overheating, and improving the stability and reliability of the equipment operation; the porous microchannel structure can quickly transfer heat, ensure efficient heat exchange in a high-temperature environment, maintain the temperature stability of the aircraft engine and the internal system of the aircraft, thereby ensuring the temperature stability of the aircraft engine and the internal system of the aircraft, reducing the risk of failure due to thermal runaway, and improving flight safety; the porous microchannel structure can quickly transfer the heat generated by the engine to the coolant, effectively reducing the engine temperature, preventing mechanical failures caused by overheating, and then the rapid cooling effect ensures that the engine operates within the optimal temperature range, improves fuel efficiency, and reduces energy waste.

[0092] Example 1: Preparation of High Thermal Conductivity Copper-Based Porous Microchannel Heat Dissipation Material

[0093] 1. Technical Solution

[0094] 1. Alloy composition: copper matrix balance, aluminum 2.0%, nickel 3.0%, titanium 0.5%, zirconium 0.3%, silicon carbide reinforcement phase 2.5%, composite pore-forming agent 6% (ammonium bicarbonate and polymethyl methacrylate microspheres in a mass ratio of 2:1), rare earth elements 0.05%, zirconium oxide 0.1%, chromium 2.0%, carbon 0.05%, nitrogen 0.03%.

[0095] 2. Process parameters: vacuum melting at 5Pa, temperature 1300℃, time 1.5 hours; gas atomization to prepare pre-alloyed powder with a particle size of 30μm; composite powder mixed at 0℃ for 60 minutes; cold isostatic pressing pressure 200MPa, laser melting power 300W, scanning speed 1100mm / s, layer thickness 35μm; sintering stage firstly heating to 350℃ at 3℃ / min and holding for 2 hours to degrease, then heating at 12℃ / min at 5×10-3Pa vacuum. The temperature was raised to 1280℃ and kept for 4 hours, and finally oil quenched at 800℃ and tempered at 200℃ for 1 hour; the microchannel processing adopted 3kW peak power laser roughing, combined with 20% nitric acid electrolyte finishing, and the processing cycle was repeated 3 times; the post-treatment pickling and passivation were ultrasonically applied in 15% hydrofluoric acid solution for 20 minutes, and the gradient cooling was first reduced to 180℃ at 8℃ / min and kept for 0.8 hours, and then cooled to room temperature at 2℃ / min, and finally oxidized at 300℃ and 20% oxygen concentration for 2 hours.

[0096] 2. Parameter Optimization Basis

[0097] The composite pore-forming agent is a combination of ammonium bicarbonate and polymethyl methacrylate microspheres in a mass ratio of 2:1, balancing the decomposition temperature gradient and pore-forming uniformity. Ammonium bicarbonate decomposes at relatively low temperatures (around 200°C) to produce gas, forming a primary pore network; while polymethyl methacrylate microspheres carbonize and shrink at higher temperatures (300-400°C), further optimizing pore connectivity. At this ratio, the synergistic effect of the two stabilizes the porosity at 25% ± 2% and the connectivity at 92% ± 1%.

[0098] 2. Laser melting parameters were set at 300W power, 1100mm / s scanning speed, and 35μm layer thickness, based on the high thermal conductivity of copper alloy. The higher power ensured complete melting of the pre-alloyed powder, forming a dense matrix. The appropriately increased scanning speed prevented local overheating that could lead to abnormal grain growth, while also ensuring uniform thickness across each cladding layer. Electron backscatter diffraction analysis revealed grain size of 3-4μm, with orientation deviation less than 10°.

[0099] 3. Implementation Effect Verification

[0100] 1. Microstructure characterization: Scanning electron microscopy observations show that the uniformity of microchannel wall thickness reaches over 95%, the pores are approximately spherical and evenly distributed, and the spacing between adjacent pores is 80-120 μm, which meets the design requirements.

[0101] 2. Thermophysical Performance Testing: Thermal conductivity measured using the laser flash method reached 380 W / (m·K) in the 20-100°C temperature range, a 15% improvement over pure copper microchannel material. Specific heat capacity testing showed a value of 380 J / (kg·K), meeting the efficient heat dissipation requirements of electronic devices.

[0102] 3. Mechanical properties evaluation: The room temperature tensile strength is 320 MPa, the elongation is 18%, and after 500 thermal cycles (-40°C to 120°C), the strength retention rate is 92% and the elongation retention rate is 88%, indicating that the material has good thermal stability.

[0103] IV. Comparative Experiment 1

[0104] 1. Technical solution of the control group: Commercially available copper-based porous materials (composition: Cu-1.5% Al-1.0% Ni, porosity 40%, connectivity 85%) were selected, and traditional powder metallurgy process (no composite pore-forming agent, single ammonium bicarbonate pore-forming) was used to prepare electronic heat dissipation components.

[0105] 2. Test standards: Porosity and connectivity are tested in accordance with GB / T24385; thermal conductivity is tested in accordance with ASTMD5470; mechanical properties are tested in accordance with ISO6892-1.

[0106] 3. Comparative data:

[0107]

[0108]

[0109] The porosity of the control group was 42% and the connectivity was 83%; the porosity of this embodiment was 25% and the connectivity was 92%.

[0110] Summary: The present invention uses composite pore-forming agents to precisely control pore parameters, avoiding the degradation of mechanical properties caused by high porosity, while optimizing connectivity and improving fluid heat transfer efficiency.

[0111] The thermal conductivity of the control group was 328 W / (m·K), while that of the embodiment was 380 W / (m·K).

[0112] Summary: Rare earth elements, zirconium oxide and the matrix work synergistically to form a high thermal conductivity network, significantly improving the material's heat transfer capability.

[0113] The tensile strength of the control group was 285 MPa, and the strength retention rate after thermal cycling was 78%. The strength of this embodiment was increased by 32%, and the thermal stability was better.

[0114] Summary: Microalloying and optimized heat treatment process effectively improve the comprehensive performance of materials and adapt to the complex thermal environment of electronic equipment.

[0115] Example 2: Preparation of high-strength and tough copper-nickel alloy aerospace heat exchange material

[0116] 1. Technical Solution

[0117] 1. Alloy composition: copper matrix balance, aluminum 3.0%, nickel 4.5%, titanium 0.8%, zirconium 0.4%, aluminum nitride reinforcement 3.5%, composite pore former 8% (ammonium bicarbonate and polymethyl methacrylate microspheres in a mass ratio of 3:1), rare earth elements 0.08%, zirconium oxide 0.15%, chromium 2.5%, carbon 0.08%, nitrogen 0.05%.

[0118] 2. Process parameters: vacuum melting at 3Pa, temperature 1350℃, time 2 hours; atomization to prepare pre-alloyed powder with a particle size of 40μm; composite powder mixing at -5℃ for 90 minutes; cold isostatic pressing pressure 250MPa, laser melting power 350W, scanning speed 1300mm / s, layer thickness 40μm; sintering stage: first heating to 380℃ at 4℃ / min and holding for 2.5 hours to degrease, then heating to 130℃ at 13℃ / min under 8×10-3Pa vacuum. The microchannel was processed by laser roughing with a peak power of 3.5kW and finishing with 25% nitric acid electrolyte, and the processing cycle was repeated 4 times. The post-processing was pickling and passivation, and ultrasonic treatment was performed in 20% hydrofluoric acid solution for 25 minutes. The temperature was gradually reduced to 190°C at a rate of 7°C / min and kept for 0.7 hours. The temperature was then cooled to room temperature at a rate of 2.5°C / min. Finally, the microchannel was oxidized at 350°C and 25% oxygen concentration for 2.5 hours.

[0119] 2. Parameter Optimization Basis

[0120] 1. The composite pore-forming agent adopts a 3:1 mass ratio to meet the more stringent strength-to-weight ratio requirements of aerospace components. The proportion of polymethyl methacrylate microspheres is increased to form a more complex three-dimensional pore network, with a porosity controlled at 30% ± 2%, while ensuring that the material density is less than 8.8g / cm 3 The gas permeation method test shows that the gas permeability is 42% higher than that of the traditional pore-making method, meeting the heat dissipation requirements of high-speed fluid working medium.

[0121] 2. During the sintering phase, the vacuum level is controlled at 8 × 10⁻³ Pa, using a high-purity nitrogen-helium (70% N₂ + 30% He) shielding gas with an oxygen content of ≤30 ppm. This environment effectively inhibits surface oxidation of the copper-nickel alloy while promoting the formation of a 10-15 nm chromium-rich carbide layer at the interface between the reinforcement phase and the matrix, improving interfacial bonding strength. Transmission electron microscopy revealed a 38% improvement in interfacial bonding strength compared to conventional processes.

[0122] 3. Implementation Effect Verification

[0123] 1. Comprehensive performance testing: Room temperature tensile strength is 385 MPa, and elongation is 15%. At 300°C, strength retention is 78%, superior to the control group's 62%. Thermal conductivity reaches 410 W / (m·K), and specific heat capacity is 360 J / (kg·K), meeting the high-temperature performance requirements of aerospace thermal management.

[0124] 2. Fluid resistance test: Using ASTM D3776 standard testing, at a flow rate of 5 m / s, the pressure drop in the microchannels of this embodiment was 120 Pa, while that of the control group was 185 Pa. Conclusion: The optimized pore structure and channel design significantly reduced fluid flow resistance and improved heat exchange efficiency.

[0125] IV. Comparative Experiment 2

[0126] 1. Control group technical solution: The copper-nickel alloy porous material recommended in the NASA technical report (composition: Cu-3.0% Ni-0.5% Cr, porosity 35%, connectivity 88%) was used to prepare the heat exchanger components using conventional powder metallurgy + sintering process.

[0127] 2. Test standards: Strength test is carried out in accordance with ASTM E8 standard; high temperature performance test is in accordance with ISO 6872 standard; fluid resistance test adopts ASTM D 3776 standard.

[0128] 3. Comparative data:

[0129]

[0130]

[0131] The control group had a room temperature strength of 320 MPa and a 300°C strength retention rate of 62%. The strength of this embodiment was increased by 20%, and the high-temperature performance was improved by 26%.

[0132] Summary: Microalloying and composite pore-forming system work synergistically, taking into account both room temperature and high temperature strength, and expanding the application temperature range of materials.

[0133] The thermal conductivity of the control group was 365 W / (m·K), while that of the embodiment was 410 W / (m·K).

[0134] Summary: The enhanced phase and optimized crystal orientation together construct an efficient heat conduction path to meet the aerospace requirements for high heat flux density transmission of materials.

[0135] Example 3: Preparation of Corrosion-Resistant Copper-Based Porous Material for Automobile Engine Cooling

[0136] 1. Technical Solution

[0137] 1. Alloy composition: copper matrix balance, aluminum 1.5%, nickel 2.5%, titanium 0.3%, zirconium 0.2%, silicon carbide reinforcement phase 1.5%, composite pore-forming agent 5% (ammonium bicarbonate and polymethyl methacrylate microspheres in a mass ratio of 1:1), rare earth elements 0.03%, zirconium oxide 0.08%, chromium 1.5%, carbon 0.03%, nitrogen 0.02%.

[0138] 2. Process parameters: vacuum melting at 2Pa, temperature 1250℃, time 1.2 hours; atomization to prepare pre-alloyed powder with a particle size of 20μm; composite powder mixing at 5℃ for 45 minutes; cold isostatic pressing pressure 180MPa, laser melting power 250W, scanning speed 900mm / s, layer thickness 25μm; sintering stage: first heating to 320℃ at 2.5℃ / min and holding for 1.5 hours to degrease, then heating to 125℃ at 11℃ / min under 6×10-3Pa vacuum The microchannel was processed by laser roughing with a peak power of 2.5kW and finishing with 15% nitric acid electrolyte, and the processing cycle was repeated twice. The post-processing was pickling and passivation, and ultrasonic treatment was performed in 12% hydrofluoric acid solution for 15 minutes. The temperature was gradually reduced to 160°C at a rate of 6°C / min and kept for 0.6 hours. The temperature was then cooled to room temperature at a rate of 1.5°C / min. Finally, the microchannel was oxidized at 250°C and 15% oxygen concentration for 1.5 hours.

[0139] 2. Parameter Optimization Basis

[0140] 1. The composite pore-forming agent uses a 1:1 mass ratio, specifically designed to meet the unique corrosion resistance requirements of automotive engine cooling systems. The ammonia produced by the decomposition of ammonium bicarbonate reacts with rare earth elements in subsequent processes, forming a 50-80nm anti-corrosion layer on the surface. The porosity is controlled at 20% ± 1.5%. Electrochemical polarization testing shows a 37% reduction in corrosion current density compared to traditional pore-forming materials, significantly improving coolant corrosion resistance.

[0141] 2. Adjustments to cold isostatic pressing and laser melting parameters were made to address the cost control requirements of large-scale automotive component production. Appropriately reducing laser power and scanning speed increased molding efficiency by 28% and reduced equipment energy consumption by 19% while maintaining molding quality. Cost accounting revealed a 24% reduction in unit component production cost compared to the previous two examples, achieving both performance and cost-effectiveness.

[0142] 3. Implementation Effect Verification

[0143] 1. Corrosion Resistance Test: Salt spray testing was conducted according to ASTM B117. After 500 hours, the corrosion depth of the material in this example was less than 15 μm, while that of the control group was 32 μm. Conclusion: The surface protective layer formed by the synergistic effect of the composite pore-forming agent and the rare earth element effectively inhibits coolant medium corrosion.

[0144] 2. Thermal Cycle Stability Test: Simulating engine operating conditions (-30°C to 150°C, 1000 cycles), the material in this example exhibited no significant microstructural degradation, with a pore collapse rate below 3%, compared to 18% for the control group. Conclusion: Optimized crystal orientation and strengthening phase distribution enhance the material's thermal fatigue resistance, making it suitable for the intense thermal shock environment of automotive engines.

[0145] IV. Comparative Experiment 3

[0146] 1. Control group technical solution: Use copper-based porous materials commonly used in the automotive industry (composition: Cu-1.0% Si-0.5% Fe, porosity 28%) and adopt traditional powder metallurgy process (single polymethyl methacrylate pore formation) to prepare engine cooling components.

[0147] 2. Test standard: Corrosion resistance test shall comply with ASTM B117 standard; thermal cycle test shall refer to SAE J1934 standard.

[0148] 3. Comparative data:

[0149]

[0150] The corrosion depth of the control group after 500 hours of salt spray test was 32 μm, while that of the embodiment was only 14 μm.

[0151] Summary: The material system of the present invention exhibits better corrosion resistance in the complex electrolyte environment of the automobile cooling system, extending the service life of the components.

[0152] The pore collapse rate of the control group after thermal cycling was 17%, while that of this embodiment was controlled at 2.8%.

[0153] Summary: The precisely controlled combination of crystal structure and pore geometry parameters enables the material to maintain structural integrity under repeated thermal expansion and contraction, ensuring long-term reliable operation.

[0154] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A metal material for porous microchannel processing, characterized in that The invention comprises the following components in percentage by mass: 0.5%-3.0% of aluminum, 2.0%-5.0% of nickel, 0.2%-1.0% of titanium, and 0.1%-0.5% of zirconium; 1.0%-4.0% of silicon carbide or aluminum nitride reinforcement phase; 3%-10% of a composite pore-forming agent with a particle size of 5-30 μm, wherein the composite pore-forming agent is composed of ammonium bicarbonate and polymethyl methacrylate microspheres in a mass ratio of 1:1-3:1; 0.03%-0.1% of a rare earth element, wherein the rare earth element is selected from at least one of lanthanum, cerium, and yttrium; 0.05%-0.2% of zirconium oxide; 1.0%-3.0% of chromium, 0.01%-0.1% of carbon, and 0.01%-0.05% of nitrogen; and the balance being a copper matrix.

2. The porous microchannel processing metal material according to claim 1, characterized in that: The grain size of the copper matrix is 1-5 μm, the grain orientation deviation is less than 15°, the porosity is controlled at 15%-35%, and the pore connectivity is greater than 90%.

3. A method for preparing a metal material for porous microchannel processing, characterized in that: A porous microchannel processing metal material according to any one of claims 1 to 2, wherein the method comprises the following steps: S1. Raw material pretreatment: The metal powder is subjected to three-dimensional vortex mixing under argon protection and ultrasonic cleaning is performed simultaneously. The cleaning time is 10-30 minutes and the temperature is 20-40°C; S2. Vacuum melting: melting the copper-based alloy under a vacuum degree of 1-10 Pa at a temperature of 1200-1400°C for 1-2 hours; S3, atomization powder making: preparing pre-alloyed powder with a particle size of 10-50 μm by gas atomization of the molten alloy; S4. Preparation of composite powder: Mix the pre-alloyed powder with the reinforcement phase and the pore-forming agent at a low temperature of -10-10°C for 30-120 minutes; S5. Molding process: cold isostatic pressing and laser cladding composite molding of the composite powder; S6. Sintering and heat treatment: sintering and quenching and tempering the formed body in stages; S7, Microchannel processing: Laser-electrolysis composite process is used to process microchannel structure; S8, post-processing: pickling, passivation and gradient cooling treatment of the workpiece; S9. Quality inspection: X-ray tomography is used to verify that the pore connectivity is greater than 90%, and electron backscatter diffraction is used to confirm that the grain orientation deviation is less than 15°.

4. The method for preparing a metal material for porous microchannel processing according to claim 3, characterized in that: The S5 forming process specifically includes: Cold isostatic pressing preforming: preparing green bodies at a pressure of 150-300 MPa; Selective laser melting: laser power 200-400W, scanning speed 800-1500mm / s, layer thickness 20-50μm to build three-dimensional structures; Rolling strengthening: The formed parts are subjected to multiple rolling with a deformation of 30%-50%, and the rolling temperature is controlled at 100-200℃.

5. The method for preparing a metal material for porous microchannel processing according to claim 3, characterized in that: The sintering and heat treatment of S6 includes: Degreasing stage: heating at 2-5℃ / min to 300-400℃ and keeping at this temperature for 1-3 hours to decompose the pore-forming agent; Vacuum sintering: heat to 1200-1350℃ at 10-3-10-2Pa vacuum and keep at this temperature for 3-6 hours; Quenching and tempering: After oil quenching at 700-900℃, temper at 100-300℃ for 0.5-2 hours, and air cool to room temperature after tempering.

6. The method for preparing a metal material for porous microchannel processing according to claim 3, characterized in that: The following conditions are applied simultaneously during the vacuum sintering stage: 0.5-2T pulsed magnetic field, frequency 10-50Hz, magnetic field direction is 45°-90° with the direction of gravity; Nitrogen-helium mixed shielding gas, nitrogen accounts for 60%-80%, flow rate is 5-15L / min, oxygen content is ≤50ppm.

7. The method for preparing a metal material for porous microchannel processing according to claim 3, characterized in that: The microchannel processing of S7 includes: Laser rough processing: Use 1064nm fiber laser with peak power of 1-5kW and pulse width of 10-100ns to form the channel prototype, with a focused spot diameter of 20-50μm; Electrolytic finishing: Use 10%-30% nitric acid electrolyte, voltage 5-15V, current density 20-50A / cm 2 , inter-pole distance 0.1-0.5mm; Circular processing: 2-4 times of laser and electrolysis alternating processing are carried out, with the laser processing depth decreasing by 20%-50% each time and the electrolysis time increasing by 30%-100%.

8. The method for preparing a metal material for porous microchannel processing according to claim 3, characterized in that: The post-processing of S8 includes: Pickling passivation: ultrasonic treatment in 10%-25% hydrofluoric acid solution for 10-30 minutes, frequency 40-100kHz, ultrasonic power 50-200W; Gradient cooling: cool to 150-200℃ at 5-10℃ / min, keep at this temperature for 0.5-1 hour, then cool to room temperature at 1-3℃ / min; Oxidation treatment: Surface passivation is performed at 200-400°C and 10%-30% oxygen concentration for 1-3 hours, with nitrogen being introduced as the carrier gas.

9. The method for preparing a metal material for porous microchannel processing according to claim 3, characterized in that: The quality inspection of S9 also includes: The pitting potential was measured in 3.5% sodium chloride solution using a three-electrode system. The working electrode consisted of the material to be tested, the reference electrode was a saturated calomel electrode, and the auxiliary electrode was a platinum electrode. The potential scan rate was 1 mV / s. The surface roughness was detected using a laser confocal microscope with a spot diameter of ≤5 μm and a scanning step length of 0.1 μm.

10. An application of a metal material for porous microchannel processing according to any one of claims 1-2, characterized in that: Used to manufacture heat dissipation components for electronic equipment, aerospace heat exchangers or automotive engine cooling systems.

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