A porous microchannel processing metal material

Abstract

The application relates to the technical field of metal materials, and discloses a kind of porous microchannel processing metal materials, comprising the following mass percentage components: aluminum 0.5%-3.0%, nickel 2.0%-5.0%, titanium 0.2%-1.0%, zirconium 0.1%-0.5%, silicon carbide or aluminum nitride reinforcing phase 1.0%-4.0%, composite pore-forming agent 3%-10%, rare earth elements 0.03%-0.1%, zirconium oxide 0.05%-0.2%, chromium 1.0%-3.0%, carbon 0.01%-0.1%, copper matrix: the balance. Through unique component design and composite preparation process, good balance between high thermal conductivity and high strength of the porous microchannel metal material is realized, the room temperature tensile strength is enhanced, the elongation rate is 18%, and the performance is still excellent after 500 times of thermal cycle. The performance improvement is mainly due to the synergistic effect of copper matrix and microalloy elements, and fine regulation of pore structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal materials, in particular to a kind of metal materials for processing porous microchannel. BACKGROUND

[0002] With the rapid development of modern industrial technology, the demand for high-efficiency heat exchange and heat dissipation materials in various fields is 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 kind of metal matrix composites with three-dimensional interconnected pore structure and precise flow channel design. The core feature is to realize high-efficiency heat transfer, fluid distribution and structural function integration through the synergistic effect of controllable pores and micron-scale channels.

[0003] However, the performance of traditional porous materials still has defects. The conventional pore-forming agent (such as single ammonium bicarbonate or polymer) has wide particle size distribution, decomposition residue, and other problems, resulting in low pore connectivity, large size deviation, and significantly reduced heat transfer efficiency. It is difficult to balance the thermal conductivity and strength of traditional copper-based porous materials, and the mechanical properties and thermal stability are insufficient in high-temperature environments. Some materials have poor corrosion resistance and thermal fatigue resistance, which seriously restricts the performance improvement and reliability of related equipment. SUMMARY

[0004] To overcome the shortcomings of the prior art, the present application provides a kind of metal materials for processing porous microchannel, solve the problem that the thermal conductivity and strength of traditional copper-based porous materials are difficult to balance, and the mechanical properties and thermal stability are insufficient in high-temperature environments.

[0005] To achieve the above purpose, the present application is realized by the following technical scheme:

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

[0007] By adopting the technical scheme, through unique component design and composite preparation process, good balance between high thermal conductivity and high strength of the porous micro-channel metal material is achieved, in the application of electronic equipment heat dissipation components, the thermal conductivity reaches 380 W / (m·K), which is 15% higher than that of traditional materials; the tensile strength at room temperature reaches 320 MPa, and the elongation rate is 18%, and the performance is still excellent after 500 times of thermal cycle, and the performance improvement is mainly due to the synergistic effect of the copper matrix and the micro-alloying element, and the fine regulation of the pore structure.

[0008] Preferably, the grain size of the copper matrix is 1-5 μm, and 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 preparation method of a porous micro-channel processing metal material is used for the porous micro-channel processing metal material, and the method comprises the following steps:

[0010] S1, raw material pretreatment: the metal powder is mixed by three-dimensional vortex under the protection of argon, and ultrasonic cleaning is simultaneously implemented, the cleaning time is 10-30 minutes, and the temperature is 20-40℃;

[0011] S2, vacuum melting: the copper-based alloy is melted under a vacuum degree of 1-10 Pa, the temperature is 1200-1400℃, and the time is 1-2 hours;

[0012] S3, atomization powdering: the molten alloy is prepared into pre-alloy powder with a particle size of 10-50 μm by gas atomization;

[0013] S4, composite powder preparation: the pre-alloy powder, the reinforcing phase and the pore-forming agent are mixed at a low temperature of-10-10℃ for 30-120 minutes;

[0014] S5, forming processing: the composite powder is subjected to cold isostatic pressing and laser cladding composite forming;

[0015] S6, sintering and heat treatment: the formed blank is subjected to stage sintering and quenching and tempering;

[0016] S7, micro-channel processing: a laser-electrolytic composite process is used to process a micro-channel structure;

[0017] S8, post-processing: the processed piece is subjected to pickling passivation and gradient cooling treatment;

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

[0019] Preferably, the body formed by the forming tool of S5 comprises:

[0020] Cold isostatic pressing preforming: pressure 150-300 MPa to prepare the green body;

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

[0022] Rolling strengthening: multi-pass rolling with 30%-50% deformation on the formed piece, rolling temperature controlled at 100-200 ℃.

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

[0024] Debinding stage: temperature raised to 300-400 ℃ at 2-5 ℃ / min, holding for 1-3 hours to decompose the pore-forming agent;

[0025] Vacuum sintering: temperature raised to 1200-1350 ℃ at 10-15 ℃ / min under vacuum degree of 10-3-10-2 Pa, holding for 3-6 hours;

[0026] Quenching and tempering: oil quenched at 700-900 ℃, then tempered at 100-300 ℃ for 0.5-2 hours, and air cooled to room temperature after tempering.

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

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

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

[0030] Preferably, the micro-channel processing of S7 includes:

[0031] Laser rough machining: 1064 nm fiber laser is used, peak power 1-5 kW, pulse width 10-100 ns to form channel rudiment, focusing spot diameter 20-50 μm;

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

[0033] Cyclic processing: 2-4 times of laser and electrolysis alternate processing are implemented, laser processing depth decreases by 20%-50% each time, and electrolysis time increases by 30%-100%.

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

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

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

[0037] Oxidation treatment: surface passivation at 200-400℃, 10%-30% oxygen concentration for 1-3 hours, with nitrogen as carrier gas.

[0038] Preferably, the mass detection of the S9 also includes:

[0039] The pitting potential is measured in a 3.5% mass fraction sodium chloride solution by a three-electrode system, the working electrode is composed of the material to be measured, the reference electrode is a saturated mercury-mercury electrode, and the auxiliary electrode is a platinum electrode, and the potential scanning rate is 1mV / s.

[0040] The surface roughness is detected by a laser confocal microscope, the light spot diameter is less than or equal to 5um, and the scanning step is 0.1um.

[0041] Preferably, the application of the porous micro-channel processing metal material is used to manufacture electronic equipment heat dissipation components, aerospace heat exchangers or automobile engine cooling systems.

[0042] The application provides a porous micro-channel processing metal material.

[0043] 1. The application realizes a good balance between high thermal conductivity and high strength of the porous micro-channel metal material through unique component design and composite preparation process, and in the application of electronic equipment heat dissipation components, the thermal conductivity reaches 380W / (m*K), which is 15% higher than that of traditional materials; the tensile strength at room temperature reaches 320MPa, the elongation rate is 18%, and the performance remains excellent after 500 times of thermal cycle, and the performance improvement is mainly due to the synergistic effect of the copper matrix and the micro-alloying element and the fine regulation of the pore structure.

[0044] 2. The application effectively solves the problems of component segregation and uneven pores in the preparation of the porous micro-channel material by adopting a multi-process integration method such as vacuum melting, atomization powder preparation, composite powder treatment, cold isostatic pressing and laser cladding forming, and by controlling the pulse magnetic field and gas environment in the sintering stage, the porosity is stably controlled at 30%±2%, the connectivity reaches 92%±1%, and the component uniformity is increased by 30%, which provides a reliable technical path for the industrialized production of high-performance porous micro-channel materials.

[0045] 3、The material in the application can adapt to various complex working conditions such as electronic equipment, aerospace, automobile engine, etc., and shows good environmental resistance, after 500 hours of salt spray test, the corrosion depth of the material is only 14 μm, which is far lower than 32 μm of the control group; after 1000 times of thermal cycling, the pore collapse rate is lower than 3%, through the synergistic effect of rare earth elements, zirconium oxide and composite pore forming agent, the special surface and interface structure formed significantly improves the corrosion resistance and thermal fatigue resistance of the material. BRIEF DESCRIPTION OF DRAWINGS

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

[0047] The technical solutions of the application will be described clearly and completely below in combination with the drawings of the application. Obviously, the described embodiments are only some of the embodiments of the application, not all. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

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

[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 processability, enabling it to be manufactured into complex micro-channel structures through various forming processes; aluminum can refine the grain size 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 grain refiner, which can refine the grain size, improve the strength and hardness of the material, and also improve the wear resistance and corrosion resistance of the material; zirconium can improve the strength and hardness of the material, and improve its wear resistance and corrosion resistance; silicon carbide or aluminum nitride as a reinforcing phase can significantly improve the hardness and wear resistance of the material, and also improve the thermal conductivity and high-temperature stability of the material; the composite pore-forming agent is composed of ammonium bicarbonate and polymethyl methacrylate microspheres, which is used to form a uniform porous structure inside the material; rare earth elements can refine the grain size, improve the strength and hardness of the material, and also improve the wear resistance and corrosion resistance of the material; zirconium oxide can improve the hardness and wear resistance of the material, and also improve the thermal conductivity and high-temperature stability of the material; chromium can improve the strength and hardness of the material, and improve its wear resistance and corrosion resistance; carbon and nitrogen can improve the strength and hardness of the material, and improve its wear resistance, which can form carbides and nitrides with the base metal, further enhancing the hardness and wear resistance of the material.

[0050] The grain size of the copper matrix is 1-5 μm, and 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, and 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 propagate because the grain boundaries can disperse the tip stress of the crack, thereby delaying the propagation of the crack; the material with an orientation deviation of less than 15° exhibits better performance during processing. In processes such as cold isostatic pressing and laser cladding forming, consistent orientation can reduce residual stress generated during processing, improve the processing precision and surface quality of the material; the porous structure with a porosity of 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 refer to the accompanying drawings Figure 1 A method for preparing a porous micro-channel processing metal material for the above-mentioned porous micro-channel processing metal material, the method comprising the following steps:

[0053] S1, raw material pretreatment: mix the metal powder under argon protection by three-dimensional vortex mixing, and simultaneously perform ultrasonic cleaning, with a cleaning time of 10-30 minutes and a temperature of 20-40°C;

[0054] S2, vacuum smelting: smelting copper-based alloy under 1-10 Pa vacuum, temperature 1200-1400℃, time 1-2 hours;

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

[0056] S4, composite powder preparation: mixing the pre-alloy powder with reinforcing phase and pore-forming agent at low temperature of -10-10℃ for 30-120 minutes;

[0057] S5, forming processing: cold isostatic pressing and laser cladding composite forming of the composite powder;

[0058] S6, sintering and heat treatment: stage sintering and quenching and tempering of the formed blank;

[0059] S7, micro-channel processing: laser-electrolytic composite process for processing micro-channel structure;

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

[0061] S9, quality detection: X-ray tomography verification of pore connectivity > 90%, and electron backscatter diffraction confirmation of grain orientation deviation < 15°.

[0062] Please refer to the attached Figure 1 , the forming tool of S5 includes:

[0063] Cold isostatic pressing pre-forming: pressure 150-300 MPa to prepare the blank;

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

[0065] Rolling reinforcement: multi-pass rolling of the formed piece with deformation amount of 30%-50%, rolling temperature controlled at 100-200℃.

[0066] Specifically, cold isostatic pressing pre-forming makes the powder preliminarily compacted and formed, selective laser melting can realize high-precision forming of complex shape, and rolling reinforcement can improve the density and strength of the material.

[0067] Please refer to the attached Figure 1 , the sintering and heat treatment of S6 includes:

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

[0069] Vacuum sintering: heating to 1200-1350℃ at 10-15℃ / min under 10-3-10-2Pa, holding for 3-6h;

[0070] Quenching and tempering: oil quenching at 700-900℃, then tempering at 100-300℃ for 0.5-2h, and air cooling to room temperature.

[0071] Specifically, the debinding 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 internal stress generated during quenching, improve the toughness and fatigue resistance of the material; finally, air cooling to room temperature can stabilize the material structure and obtain good comprehensive mechanical properties.

[0072] Please refer to the attached Figure 1 During the vacuum sintering stage, the following conditions are applied simultaneously:

[0073] 0.5-2T pulse magnetic field, frequency 10-50Hz, magnetic field direction at 45°-90° angle with gravity direction;

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

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

[0076] Please refer to the attached Figure 1 The microchannel processing of S7 includes:

[0077] Laser rough machining: using a 1064nm fiber laser, peak power 1-5kW, pulse width 10-100ns to form a channel sketch, focusing spot diameter 20-50μm;

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

[0079] Cyclic processing: 2-4 times of laser and electrolytic processing alternately, each time of laser processing depth decreases by 20%-50%, electrolytic time increases by 30%-100%.

[0080] Specifically, the laser rough machining can form the rudiment of the micro-channel on the material surface, providing the basic structure for the subsequent finishing machining. The laser machining utilizes the high-energy density laser beam to make the material locally melt or vaporize through the instantaneous high temperature, thereby forming the required micro-channel shape on the material surface; the electrolytic finishing process utilizes the electrochemical reaction to finely trim the micro-channel surface after the laser processing, removes the burrs, residues and irregular parts on the micro-channel surface through the electrolytic effect, makes the inner wall of the micro-channel more smooth and flat, and improves the quality and precision of the micro-channel; the cyclic processing mode can gradually optimize the shape and size of the micro-channel, and ensure the precision and quality of the micro-channel.

[0081] Please refer to the attached Figure 1 The post-processing of S8 includes:

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

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

[0084] Oxidation treatment: surface passivation at 200-400℃ and 10%-30% oxygen concentration for 1-3 hours, with nitrogen as the carrier gas.

[0085] Specifically, the pickling and passivation function 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 material surface; the purpose of gradient cooling is to reduce the residual stress in the material, avoid the concentration of thermal stress caused by rapid cooling, thereby improving the dimensional stability and mechanical properties of the material, and the slow cooling process can gradually release the thermal stress in the material, reduce cracks and deformation caused by excessive temperature gradient; the purpose of oxidation treatment is to form a uniform oxide film on the material surface, further improve the corrosion resistance and oxidation resistance of the material, and by controlling the oxygen concentration and temperature, the thickness and composition of the oxide film can be accurately controlled, and nitrogen as the carrier gas can ensure that the oxidation process is carried out in a stable atmosphere, avoiding the influence of other impurity gases on the oxide film.

[0086] Please refer to the attached Figure 1 The quality detection of S9 also includes:

[0087] The point corrosion potential is measured in a three-electrode system in a 3.5% mass fraction sodium chloride solution, the working electrode is composed of the material to be tested, the reference electrode is a saturated calomel electrode, and the auxiliary electrode is a platinum electrode, and the potential scanning rate is 1 mV / s;

[0088] The surface roughness is detected by a laser confocal microscope, the spot diameter is less than or equal to 5 microns, and the scanning step is 0.1 microns.

[0089] Specifically, by measuring the point corrosion potential, the corrosion resistance of the material in a specific environment can be evaluated. The higher the point corrosion potential, the better the point corrosion 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 production. By comparing the point corrosion potentials of different batches of materials, quality problems in the production process can be found in time, so that adjustments and improvements can be made. The laser confocal microscope can provide high-resolution surface topography images, accurately measuring the surface roughness and microstructure. By detecting the surface roughness, the quality control of the material during processing can be evaluated. The lower the surface roughness, the better the surface quality of the material, which can reduce fluid flow resistance, improve heat exchange efficiency, and also help improve the corrosion resistance of the material.

[0090] The application of a porous microchannel processing metal material for manufacturing electronic device heat dissipation components, 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 quickly transferred from the heat-generating components of the electronic device to the surrounding environment. High porosity and good pore connectivity further optimize the heat conduction path, improving heat dissipation efficiency, which can effectively reduce the internal temperature of the electronic device, prolong the service life of the device, reduce the failure rate caused by overheating, and improve the stability and reliability of the device operation. The porous microchannel structure can quickly transfer heat, ensuring efficient heat exchange in high-temperature environments and maintaining the temperature stability of the internal systems of the aircraft engine and aircraft, thereby reducing the risk of thermal runaway and improving flight safety. The porous microchannel structure can quickly transfer the heat generated by the engine to the cooling liquid, effectively reducing the engine temperature, preventing mechanical failure caused by overheating, and ensuring the engine operates within the optimal temperature range, improving fuel efficiency, and reducing energy waste.

[0092] Example 1: Preparation of high-thermal-conductivity copper-based porous microchannel heat dissipation material

[0093] I. Technical solution

[0094] 1. Alloy composition: copper matrix balance, aluminum 2.0%, nickel 3.0%, titanium 0.5%, zirconium 0.3%, silicon carbide reinforcing 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 vacuum degree 5 Pa, temperature 1300 ℃, time 1.5 hours; gas atomization to prepare pre-alloy powder with particle size 30 μm; composite powder mixed at 0 ℃ for 60 minutes; cold isostatic pressing pressure 200 MPa, laser melting power 300 W, scanning speed 1100 mm / s, layer thickness 35 μm; sintering stage first debinding by increasing temperature to 350 ℃ at 3 ℃ / min and holding for 2 hours, then increasing temperature to 1280 ℃ at 12 ℃ / min under a vacuum degree of 5×10-3 Pa and holding for 4 hours, finally oil quenching at 800 ℃ and tempering at 200 ℃ for 1 hour; micro-channel processing using a peak power of 3 kW laser rough machining, combined with 20% nitric acid electrolyte finishing, and cyclic processing 3 times; post-processing pickling and passivation in 15% hydrofluoric acid solution for 20 minutes, gradient cooling first decreasing to 180 ℃ at 8 ℃ / min and holding for 0.8 hours, then cooling to room temperature at 2 ℃ / min, and finally oxidation treatment at 300 ℃ under 20% oxygen concentration for 2 hours.

[0096] II. Basis for parameter optimization

[0097] 1. The composite pore-forming agent is composed of ammonium bicarbonate and polymethyl methacrylate microspheres in a mass ratio of 2:1, taking into account the decomposition temperature gradient and pore uniformity. Ammonium bicarbonate decomposes at a relatively low temperature (around 200 ℃) to generate gas and form a primary pore network; polymethyl methacrylate microspheres carbonize and shrink at a relatively high temperature (300-400 ℃) to further optimize pore connectivity. At this ratio, the porosity is stabilized at 25%±2% and the connectivity reaches 92%±1% through the synergistic effect of the two.

[0098] 2. The laser melting parameters are set to power 300 W, scanning speed 1100 mm / s, and layer thickness 35 μm, based on the high thermal conductivity characteristics of copper alloy. Higher power ensures that the pre-alloy powder is fully melted to form a dense matrix; appropriately increasing the scanning speed avoids local overheating leading to abnormal grain growth, while ensuring the uniformity of each layer of cladding thickness. Electron backscatter diffraction detection shows that the grain size is controlled within 3-4 μm, and the orientation deviation is less than 10°.

[0099] III. Verification of implementation effect

[0100] 1. Microstructure characterization: through scanning electron microscope observation, the micro-channel wall thickness uniformity reaches more than 95%, the pores are approximately spherical and uniformly distributed, and the distance between adjacent pores is 80-120 μm, meeting the design requirements.

[0101] 2. Thermophysical property test: The thermal conductivity is measured by laser flash method, and the thermal conductivity reaches 380 W / (m·K) in the temperature range of 20-100℃, which is increased by 15% compared with the pure copper micro-channel material. The specific heat capacity test shows that the specific heat capacity is 380 J / (kg·K), which meets the high-efficiency heat dissipation demand of electronic equipment.

[0102] 3. Mechanical property evaluation: The tensile strength at room temperature is 320 MPa, and the elongation is 18%. After 500 times of thermal cycle (-40℃ to 120℃), the strength retention rate is 92%, and the elongation retention rate is 88%, indicating that the material has good thermal stability.

[0103] Four, comparative experiment 1

[0104] 1. Control group technical scheme: Selecting a commercially available copper-based porous material (composition: Cu-1.5%Al-1.0%Ni, porosity 40%, connectivity 85%), using traditional powder metallurgy process (without composite pore forming agent, single ammonium bicarbonate pore forming) to prepare electronic heat dissipation components.

[0105] 2. Test standard: According to GB / T24385 standard to test porosity and connectivity; thermal conductivity test refers to ASTM D5470 standard; mechanical property test executes ISO6892-1 standard.

[0106] 3. Comparison data:

[0107]

[0108]

[0109] The porosity of the control group is 42%, and the connectivity is 83%; the porosity of the present embodiment is 25%, and the connectivity is 92%.

[0110] Summary: The present application precisely controls the pore parameters by composite pore forming agent, avoids the mechanical property decline caused by high porosity, and optimizes the connectivity to improve the fluid heat transfer efficiency.

[0111] The thermal conductivity of the control group is 328 W / (m·K), and the thermal conductivity of the present embodiment reaches 380 W / (m·K).

[0112] Summary: The rare earth elements, zirconium oxide and the matrix synergistically form a high thermal conductivity network, which significantly improves the material's heat transport capacity.

[0113] The tensile strength of the control group is 285 MPa, and the strength retention rate after thermal cycle is 78%; the strength of the present embodiment is increased by 32%, and the thermal stability is better.

[0114] Summary: Micro-alloying and optimizing the heat treatment process effectively improve the comprehensive performance of the material, and adapt to the complex thermal environment of electronic equipment.

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

[0116] I. Technical solution

[0117] 1. Alloy composition: copper matrix, aluminum 3.0%, nickel 4.5%, titanium 0.8%, zirconium 0.4%, aluminum nitride reinforcing phase 3.5%, composite pore-forming agent 8% (consisting of 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%, and nitrogen 0.05%.

[0118] 2. Process parameters: vacuum melting, vacuum degree 3 Pa, temperature 1350°C, time 2 hours; atomization to prepare pre-alloy powder with particle size 40 μm; mixing of composite powder at -5°C for 90 minutes; cold isostatic pressing at a pressure of 250 MPa, laser melting power 350 W, scanning speed 1300 mm / s, layer thickness 40 μm; sintering stage: first, debinding at 4°C / min to 380°C for 2.5 hours, then heating at 13°C / min to 1300°C under a vacuum degree of 8 x 10-3 Pa for 5 hours, and finally oil quenching at 850°C followed by tempering at 250°C for 1.5 hours; micro-channel processing: rough machining with a peak power of 3.5 kW laser, followed by finishing with 25% nitric acid electrolyte, and cyclic processing 4 times; post-processing: acid pickling and passivation in 20% hydrofluoric acid solution for 25 minutes, gradient cooling: first, cooling at 7°C / min to 190°C for 0.7 hours, then cooling at 2.5°C / min to room temperature, and finally oxidation treatment at 350°C under an oxygen concentration of 25% for 2.5 hours.

[0119] II. Basis for parameter optimization

[0120] 1. The composite pore-forming agent has a mass ratio of 3:1, which is suitable for the more stringent strength-to-weight ratio requirements of aerospace components. The proportion of polymethyl methacrylate microspheres is increased, forming a more complex three-dimensional pore network, with a porosity of 30% ± 2% and a material density of less than 8.8 g / cm 3 . The gas permeability is improved by 42% compared to traditional pore-forming methods through gas permeation testing, meeting the heat dissipation requirements of high-speed fluid working media.

[0121] 2. The vacuum degree during the sintering stage is controlled at 8 x 10-3 Pa, with high-purity nitrogen-helium (70% N2 + 30% He) protective gas, with oxygen content ≤ 30 ppm. This environment can effectively inhibit the oxidation of the copper-nickel alloy surface, while promoting the interface reaction between the reinforcing phase and the matrix to form a 10-15 nm chromium-rich carbide layer, improving the interface bonding strength. Through transmission electron microscopy observation, the interface bonding strength is improved by 38% compared to conventional processes.

[0122] III. Verification of implementation effects

[0123] 1. Comprehensive performance test: room temperature tensile strength 385 MPa, elongation 15%; at 300°C, strength retention rate 78%, better than the control group's 62%. Thermal conductivity 410 W / (m-K), specific heat capacity 360 J / (kg-K), meeting the requirements of aerospace thermal management for high-temperature performance of materials.

[0124] 2. Fluid resistance test: using ASTM D3776 standard test, at a flow rate of 5 m / s, the pressure drop of the microchannel of the embodiment is 120 Pa, and that of the control group is 185 Pa. Summary: the optimized pore structure and channel design significantly reduce the fluid flow resistance and improve the heat exchange efficiency.

[0125] Four, comparative experiment 2

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

[0127] 2. Test standard: strength test according to ASTM E8 standard; high-temperature performance test according to ISO 6872 standard; fluid resistance test using ASTM D3776 standard.

[0128] 3. Comparison data:

[0129]

[0130]

[0131] The room temperature strength of the control group is 320 MPa, and the strength retention rate at 300°C is 62%; the strength of the embodiment is increased by 20%, and the high-temperature performance is increased by 26%.

[0132] Summary: micro-alloying and composite pore-making system work together, taking into account room temperature and high-temperature strength, expanding the application temperature range of the material.

[0133] The thermal conductivity of the control group is 365 W / (m-K), and that of the embodiment is 410 W / (m-K).

[0134] Summary: the enhanced phase and the optimized crystal orientation jointly construct an efficient heat conduction path, meeting the demand of aerospace for high heat flux density transmission of materials.

[0135] Example 3: preparation of corrosion-resistant copper-based porous material for cooling of automobile engine

[0136] I. Technical scheme

[0137] 1. Alloy composition: copper matrix balance, aluminum 1.5%, nickel 2.5%, titanium 0.3%, zirconium 0.2%, silicon carbide reinforcing 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 vacuum degree 2 Pa, temperature 1250℃, time 1.2 hours; atomization to prepare particle size 20μm pre-alloyed powder; composite powder mixed at 5℃ for 45 minutes; cold isostatic pressing pressure 180MPa, laser melting power 250W, scanning speed 900mm / s, layer thickness 25μm; sintering stage first debind at 2.5℃ / min to 320℃ for 1.5 hours, then at 6×10-3Pa vacuum degree, 11℃ / min to 1250℃ for 3.5 hours, finally oil quenching at 750℃ and tempering at 150℃ for 0.8 hours; micro-channel processing uses peak power 2.5kW laser rough machining, cooperates with 15% nitric acid electrolyte finishing, and circulates processing 2 times; post-processing pickling and passivation in 12% hydrofluoric acid solution for 15 minutes, gradient cooling first 6℃ / min to 160℃ for 0.6 hours, then 1.5℃ / min to room temperature, finally oxidation treatment at 250℃, 15% oxygen concentration for 1.5 hours.

[0139] II. Parameter optimization basis

[0140] 1. The composite pore-forming agent uses a mass ratio of 1:1, which is aimed at the special requirements of the material's corrosion resistance for the cooling system of an automobile engine. The ammonia gas produced by the decomposition of ammonium bicarbonate can react with rare earth elements in the subsequent process, forming a 50-80nm corrosion-resistant layer on the surface. The porosity is controlled at 20%±1.5%, and the corrosion current density is reduced by 37% compared to traditional pore-forming materials through electrochemical polarization testing, significantly improving the corrosion resistance to cooling liquid.

[0141] 2. Adjustment of cold isostatic pressing and laser melting parameters, considering the cost control requirements of large-scale production of automobile parts. Properly reducing the laser power and scanning speed can improve the forming efficiency by 28% and reduce the equipment energy consumption by 19% while ensuring the quality of the formed parts. Through cost accounting, the production cost per part is reduced by 24% compared to the previous two examples, combining performance and economy.

[0142] III. Implementation effect verification

[0143] 1. Corrosion resistance test: according to the salt spray test standard ASTM B117, the corrosion depth of the material in this example is less than 15μm after 500 hours, while the control group is 32μm. Conclusion: the surface protective layer formed by the synergistic effect of the composite pore-forming agent and rare earth elements effectively inhibits the corrosion of the cooling liquid medium.

[0144] 2. Thermal cycle stability test: simulate engine working condition (-30℃ to 150℃, 1000 cycles), the microstructure of the material of the present embodiment has no obvious deterioration, the pore collapse rate is less than 3%, and the control group reaches 18%. Summary: Optimized crystal orientation and strengthening phase distribution improve the thermal fatigue resistance of the material, and adapt to the severe thermal shock environment of the automobile engine.

[0145] Four, comparative experiment 3

[0146] 1. Control group technical scheme: select the copper-based porous material commonly used in the automobile industry (composition: Cu-1.0%Si-0.5%Fe, porosity 28%), and prepare the engine cooling component by using the traditional powder metallurgy process (single polymethyl methacrylate pore forming).

[0147] 2. Test standard: corrosion resistance test is performed according to ASTM B117 standard; thermal cycle test refers to SAE J1934 standard.

[0148] 3. Comparative data:

[0149]

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

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

[0152] ·The pore collapse rate of the control group after thermal cycle is 17%, and that of the present embodiment is controlled at 2.8%.

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

[0154] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A porous microchannel processing metal material, characterized by, It is prepared and contains the following mass percentage components: aluminum 0.5%-3.0%, nickel 2.0%-5.0%, titanium 0.2%-1.0%, zirconium 0.1%-0.5%; silicon carbide or aluminum nitride reinforcing phase 1.0%-4.0%; composite pore forming agent 3%-10% 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; rare earth elements 0.03%-0.1%, the rare earth elements being selected from at least one of lanthanum, cerium, and yttrium; zirconium oxide 0.05%-0.2%; chromium 1.0%-3.0%, carbon 0.01%-0.1%, nitrogen 0.01%-0.05%; copper matrix: balance.

2. The porous microchannel processing metal material of claim 1, wherein: The grain size of the copper matrix is 1-5 μm, and 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 producing a porous microchannel processing metal material, characterized by comprising the steps of: A porous microchannel processing metal material for the method of any one of claims 1-2, the method comprising the following steps: S1, raw material pretreatment: the metal powder is mixed by three-dimensional vortex under argon protection, and ultrasonic cleaning is simultaneously implemented, the cleaning time is 10-30 minutes, and the temperature is 20-40℃; S2, vacuum melting: the copper-based alloy is melted under a vacuum degree of 1-10 Pa, the temperature is 1200-1400℃, and the time is 1-2 hours; S3, atomization powdering: the molten alloy is prepared into pre-alloy powder with a particle size of 10-50 μm by gas atomization; S4, composite powder preparation: the pre-alloy powder is mixed with the reinforcing phase and the pore forming agent at a low temperature of -10-10℃ for 30-120 minutes; S5, forming processing: the composite powder is subjected to cold isostatic pressing and laser cladding combined forming; S6, sintering and heat treatment: the formed body is subjected to staged sintering and quenching and tempering; S7, microchannel processing: a laser-electrolysis combined process is used to process a microchannel structure; S8, post-processing: the processed piece is subjected to pickling, passivation, and gradient cooling treatment; S9, quality detection: X-ray tomography is used to verify that the pore connectivity is >90%, and electron backscatter diffraction is used to confirm that the grain orientation deviation is <15°.

4. The method of claim 3, wherein the metal material is a porous microchannel processing material. The formed body of S5 includes: Cold isostatic pressing pre-forming: a pressure of 150-300 MPa is used to prepare a blank; Selective laser melting: a laser power of 200-400 W, a scanning speed of 800-1500 mm / s, and a layer thickness of 20-50 μm are used to construct a three-dimensional structure; Rolling reinforcement: the formed piece is subjected to multi-pass rolling with a deformation amount of 30%-50%, and the rolling temperature is controlled at 100-200℃.

5. The method of claim 3, wherein the metal material is a porous microchannel processing material. The sintering and heat treatment of S6 includes: Degreasing stage: the temperature is raised to 300-400℃ at a rate of 2-5℃ / min, and the temperature is maintained for 1-3 hours to decompose the pore forming agent; Vacuum sintering: the temperature is raised to 1200-1350℃ at a rate of 10-15℃ / min under a vacuum degree of 10⁻³-10⁻² Pa, and the temperature is maintained for 3-6 hours; Quenching and tempering: oil quenching at 700-900℃, and tempering at 100-300℃ for 0.5-2 hours, and air cooling to room temperature after tempering.

6. The method of making a porous microchannel processing metal material according to claim 3, wherein: The following conditions are applied synchronously during the vacuum sintering stage: 0.5-2T pulse magnetic field, frequency 10-50Hz, magnetic field direction and gravity direction angle 45°-90°; Nitrogen-helium mixed protective gas, nitrogen content 60%-80%, flow rate 5-15L / min, oxygen content ≤50ppm.

7. The method of making a porous microchannel processing metal material according to claim 3, wherein: The micro-channel processing of S7 comprises: Laser rough machining: using 1064nm fiber laser, peak power 1-5kW, pulse width 10-100ns to form channel rudiment, focusing spot diameter 20-50μm; Electrolytic finishing: using 10%-30% nitric acid electrolyte, voltage 5-15V, current density 20-50A / cm², inter-electrode distance 0.1-0.5mm; Cyclic processing: implementing 2-4 times of laser and electrolysis alternate processing, laser processing depth decreasing by 20%-50% each time, electrolysis time increasing by 30%-100%.

8. The method of making a porous microchannel processing metal material according to claim 3, wherein: The post-processing of S8 comprises: Pickling and passivation: ultrasonic treatment in 10%-25% hydrofluoric acid solution for 10-30 minutes, frequency 40-100kHz, ultrasonic power 50-200W; Gradient cooling: reducing to 150-200℃ at 5-10℃ / min, holding for 0.5-1 hour, then cooling to room temperature at 1-3℃ / min; Oxidation treatment: surface passivation at 200-400℃, 10%-30% oxygen concentration for 1-3 hours, nitrogen gas as carrier gas.

9. The method of making a porous microchannel processing metal material according to claim 3, wherein: The quality detection of S9 further comprises: Measuring pitting potential in 3.5% mass fraction sodium chloride solution by three-electrode system, working electrode composed of material to be tested, reference electrode saturated calomel electrode, auxiliary electrode platinum electrode, potential scanning rate 1mV / s; Using laser confocal microscope to detect surface roughness, spot diameter ≤5μm, scanning step 0.1μm.

10. Use of a porous microchannel processing metal material according to any one of claims 1 to 2, characterized in that For manufacturing electronic equipment heat dissipation components, aerospace heat exchangers or automobile engine cooling systems. For manufacturing electronic equipment heat dissipation components, aerospace heat exchangers or automobile engine cooling systems.

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