Composite material and preparation method therefor, plate body, housing assembly, and electronic device
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-10-13
- Publication Date
- 2026-08-13
Smart Images
Figure CN2025127219_13082026_PF_FP_ABST
Abstract
Description
Composite materials and their preparation methods, plate bodies, housing components and electronic devices
[0001] This application claims priority to Chinese Patent Application No. 202510142353.3, filed on February 8, 2025, entitled "Composite Material and Preparation Method Thereof, Plate Body, Shell Assembly and Electronic Device", the entire contents of which are incorporated herein by reference. Technical Field
[0002] This application relates to the field of electronic product technology, and in particular to a composite material, its preparation method, a plate, a housing assembly, and an electronic device. Background Technology
[0003] Electronic devices include a housing assembly, a display screen mounted on the outside of the housing assembly, and electronic components mounted inside the housing assembly. The housing assembly is used to support and fix the electronic components. For lightweight design of electronic devices, the housing assembly needs to have high yield strength and be thin. Existing housing assemblies are mostly made of 0.4mm thick aluminum alloy, stainless steel, or copper alloy. However, the plates made of aluminum alloy, stainless steel, or copper alloy cannot simultaneously meet the requirements of high yield strength and thinness.
[0004] Therefore, it is necessary to develop lightweight, thin, and high-strength composite materials.
[0005] Application content
[0006] This application provides a composite material and its preparation method, a plate, a shell assembly, and an electronic device, which have the advantages of being lightweight and thin with high strength.
[0007] This application provides a composite material comprising a matrix and a reinforcing phase, wherein the reinforcing phase is dispersed within the matrix; the matrix comprises aluminum, magnesium, silicon, copper, and manganese; the reinforcing phase is silicon carbide, the mass fraction of the reinforcing phase is G1, and the mass fraction of the matrix is G2, wherein G1 and G2 satisfy the following conditions: 20% ≤ G1 / (G1+G2) ≤ 40%, 60% ≤ G2 / (G1+G2) ≤ 80%.
[0008] In this application, silicon carbide possesses extremely high elastic modulus, hardness, chemical inertness, excellent high-temperature performance, good thermal conductivity, and a low coefficient of thermal expansion. Dispersing silicon carbide on an Al-Mg-Si-Cu-Mn alloy matrix significantly improves the composite material's elastic modulus, strength, hardness, wear resistance, heat resistance, thermal stability, and thermal conductivity. It also reduces the degree of dimensional and shape changes caused by temperature variations, thus improving the composite material's structural stability. Simultaneously, while maintaining high strength, silicon carbide is lighter than some traditional reinforcing materials (alumina, titanium carbide, etc.), resulting in a lighter composite material.
[0009] Manganese plays a role in solid solution strengthening and grain refinement, thereby improving the strength, hardness, low-temperature toughness, and corrosion resistance of composite materials. Compared to traditional age-hardened aluminum alloys, where the strengthening precipitates (coherent / semi-coherent Mg2Si or Cu-rich precipitates) grow into incoherent coarse phases during subsequent hot working (e.g., 250℃), leading to a sharp decrease in yield strength—the so-called annealing softening phenomenon—manganese's solid solution strengthening and grain refinement capabilities are not reduced by subsequent heating, thus improving the composite material's resistance to annealing softening.
[0010] If the silicon carbide content is below 20%, its effect on improving the elastic modulus of the composite material is poor; if the silicon carbide content is above 40%, it will lead to excessive brittleness in the composite material, posing a risk of cracking or even breakage during subsequent processing. Therefore, a silicon carbide content of 20%-40% can improve the elastic modulus of the composite material and reduce the risk of cracking and damage during processing.
[0011] In one possible design, the median particle size D1 of silicon carbide satisfies: 0.5μm≤D1≤3μm; and the median particle size D2 of the matrix satisfies: 2μm≤D2≤20μm.
[0012] In this application, if the median particle size of silicon carbide is too small, it increases the processing difficulty and cost of silicon carbide powder; if the median particle size of silicon carbide powder is too large, the mixing uniformity of silicon carbide powder in the alloy matrix will decrease. The median particle size of silicon carbide in this application is 0.5μm-3μm, which reduces the cost of silicon carbide powder, thereby reducing the cost of composite materials, and is conducive to improving the mixing uniformity of silicon carbide in the alloy matrix, thereby improving the strength, hardness, fatigue resistance, thermal conductivity and processing performance of composite materials.
[0013] If the median particle size of the matrix is too small, it increases the processing difficulty and cost of the matrix; if the median particle size of the matrix is too large, the mixing uniformity of silicon carbide in the alloy matrix will decrease. Furthermore, a matrix with a large particle size will affect the strength, toughness, and elongation of the composite material. The median particle size of the matrix in this application is 2μm-20μm, which reduces the cost of the matrix, thereby reducing the cost of the composite material. It also helps to improve the mixing uniformity of silicon carbide in the matrix, thus improving the strength, hardness, fatigue resistance, thermal conductivity, and processing performance of the composite material. At the same time, a smaller particle size matrix can further improve the strength, toughness, and elongation of the composite material.
[0014] In one possible design, the mass of magnesium (g1) satisfies: 0.5% ≤ g1 / G2 ≤ 1.2%; the mass of silicon (g2) satisfies: 0.5% ≤ g2 / G2 ≤ 1.0%; the mass of copper (g3) satisfies: 0.4% ≤ g3 / G2 ≤ 1.6%; the mass of manganese (g4) satisfies: 0 < g4 / G2 ≤ 0.8%; and the mass of aluminum (g5) satisfies: 95.4% ≤ g5 / G2 < 98.6%.
[0015] In this application, magnesium can improve the ultimate tensile strength and yield strength of the composite material. If the mass fraction of magnesium is low, the ultimate tensile strength and yield strength of the composite material will decrease. On the other hand, if the content of magnesium is too high, it will increase the brittleness of the composite material and make it difficult to process the composite material. Therefore, this application limits the mass of magnesium to 0.5%-1.2% of the matrix mass.
[0016] Silicon can form a reinforcing phase with magnesium to improve the yield strength and hardness of composite materials. However, excessive silicon content will reduce the elongation of composite materials. Therefore, this application limits the mass of silicon to 0.5%-1.0% of the matrix mass.
[0017] Copper has a certain solid solution strengthening effect, which can significantly improve the fluidity, ultimate tensile strength and hardness of composite materials. If the content of copper is high, it will reduce the plasticity of composite materials and increase the risk of cracking during the later molding process. Therefore, this application limits the mass of copper to 0.4%-1.6% of the matrix mass.
[0018] The matrix contains both magnesium and manganese. Manganese acts as a reinforcing agent, ensuring the ultimate tensile strength of the composite material while reducing the magnesium content. Simultaneously, manganese promotes the uniform precipitation of Mg5Al8 compounds, improving the corrosion resistance and weldability of the composite material. However, if the manganese content is too high, its effect on improving the elongation of the composite material is not significant, leading to increased costs. Therefore, this application limits the mass of manganese to less than or equal to 0.8% of the matrix mass.
[0019] In one possible design, the composite material satisfies at least one of the following three conditions: the density of the composite material is less than or equal to 4 g / cm3, the Vickers hardness of the composite material is greater than or equal to 130 HV, and the elastic modulus of the composite material is greater than or equal to 100 GPa.
[0020] In this application, the density of the composite material is less than or equal to 4 g / cm3, the Vickers hardness of the composite material is greater than or equal to 130 HV, and the elastic modulus of the composite material is greater than or equal to 100 GPa, which gives the composite material the advantages of being lightweight, thin, high-strength, and having strong resistance to annealing softening.
[0021] In one possible design, the composite material also includes graphene dispersed within the matrix; the mass of the graphene is G3, and G3 satisfies: G3 / (G1+G2+G3)≤0.5%.
[0022] In this application, the high strength and high modulus properties of graphene can effectively transfer loads, thereby increasing the tensile strength, yield strength, and hardness of the composite material. Appropriate amounts of graphene can promote the optimization of the microstructure within the alloy matrix, such as refining grains or inhibiting crack propagation, which helps improve the toughness and fatigue resistance of the composite material. Graphene possesses extremely high electron mobility and good thermal conductivity, thus significantly enhancing the electrical and thermal conductivity of the composite material. Graphene can reduce the overall density of the composite material without sacrificing mechanical properties, thereby achieving weight reduction. Graphene's hydrophobicity and chemical inertness allow it to form a protective barrier, preventing moisture and other corrosive media from contacting the alloy matrix, thereby improving the corrosion resistance of the composite material. Graphene can also improve the processability of the composite material, reducing internal stress during the molding process and thus lowering the risk of cracking during processing.
[0023] If the graphene content is too high, the high concentration of graphene may weaken the interfacial bonding force between the graphene and the alloy matrix. Under external force, cracks or delamination may easily form at the interface, thus affecting the strength and toughness of the composite material. Excessive graphene may cause embrittlement of the composite material, that is, a decrease in the ductility and impact toughness of the composite material, making it more prone to fracture. Therefore, a graphene content of no more than 0.5% can improve the strength, toughness, and ductility of the composite material.
[0024] In one possible design, the graphene is redox graphene.
[0025] In this application, redox graphene is used, which is beneficial to improving the dispersion uniformity of graphene in the alloy matrix and to enhancing the electrical conductivity, thermal conductivity, strength and toughness of the composite material.
[0026] In one possible design, the yield strength of the composite material is greater than or equal to 300 MPa.
[0027] In this application, the yield strength of the composite material is greater than or equal to 300 MPa, which improves the strength and reduces the weight of the composite material.
[0028] This application provides a plate, at least a portion of which is made of the composite material described in any one of the preceding claims; the composite material includes a matrix and a reinforcing phase, the reinforcing phase being dispersed in the matrix; the matrix includes aluminum, magnesium, silicon, copper, and manganese; the reinforcing phase is silicon carbide, the mass of the reinforcing phase is G1, the mass of the matrix is G2, and G1 and G2 satisfy: 20% ≤ G1 / (G1+G2) ≤ 40%, 60% ≤ G2 / (G1+G2) ≤ 80%.
[0029] In this application, the plate made of the aforementioned composite material has the advantages of being lightweight, thin, high-strength, and having strong resistance to annealing softening, which is beneficial for realizing the design of lightweight plates. The composite material contains manganese, which can reduce or even avoid the annealing softening phenomenon caused by the growth of coherent / semi-coherent Mg2Si or Cu-rich phases during the hot working of the plate made of the composite material, thereby improving the yield strength and hardness of the plate made of the composite material.
[0030] In one possible design, the median particle size D1 of silicon carbide satisfies: 0.5μm≤D1≤3μm; and the median particle size D2 of the matrix satisfies: 2μm≤D2≤20μm.
[0031] In this application, if the median particle size of silicon carbide is too small, it increases the processing difficulty and cost of silicon carbide powder; if the median particle size of silicon carbide powder is too large, the mixing uniformity of silicon carbide powder in the alloy matrix will decrease. The median particle size of silicon carbide in this application is 0.5μm-3μm, which reduces the cost of silicon carbide powder, thereby reducing the cost of composite materials, plates, and electronic devices. It also helps to improve the mixing uniformity of silicon carbide in the alloy matrix, thereby improving the strength, hardness, fatigue resistance, thermal conductivity, and processing performance of composite materials and plates.
[0032] If the median particle size of the matrix is too small, it increases the processing difficulty and cost of the matrix; if the median particle size of the matrix is too large, the mixing uniformity of silicon carbide in the alloy matrix will decrease. At the same time, a matrix with a large particle size will affect the strength, toughness, and elongation of the composite material. The median particle size of the matrix in this application is 2μm-20μm, which reduces the cost of the matrix, thereby reducing the cost of the composite material, plate, and electronic equipment. It also helps to improve the mixing uniformity of silicon carbide in the matrix, which is beneficial to improving the strength, hardness, fatigue resistance, thermal conductivity, and processing performance of the composite material and plate. In addition, a smaller particle size matrix can further improve the strength, toughness, and elongation of the composite material and plate.
[0033] In one possible design, the mass of magnesium (g1) satisfies: 0.5% ≤ g1 / G2 ≤ 1.2%; the mass of silicon (g2) satisfies: 0.5% ≤ g2 / G2 ≤ 1.0%; the mass of copper (g3) satisfies: 0.4% ≤ g3 / G2 ≤ 1.6%; the mass of manganese (g4) satisfies: 0 < g4 / G2 ≤ 0.8%; and the mass of aluminum (g5) satisfies: 95.4% ≤ g5 / G2 < 98.6%.
[0034] In this application, magnesium can improve the ultimate tensile strength and yield strength of composite materials. If the mass fraction of magnesium is low, the ultimate tensile strength and yield strength of composite materials and plates will decrease. On the other hand, excessive magnesium content will increase the brittleness of composite materials, which is not conducive to the subsequent processing of composite materials. Therefore, this application limits the mass of magnesium to 0.5%-1.2% of the matrix mass.
[0035] Silicon can form a reinforcing phase with magnesium to improve the yield strength and hardness of composite materials. However, excessive silicon content will reduce the elongation of composite materials. Therefore, this application limits the mass of silicon to 0.5%-1.0% of the matrix mass.
[0036] Copper has a certain solid solution strengthening effect, which can significantly improve the fluidity, ultimate tensile strength and hardness of composite materials. If the content of copper is high, it will reduce the plasticity of composite materials and increase the risk of cracking during the later molding process. Therefore, this application limits the mass of copper to 0.4%-1.6% of the matrix mass.
[0037] The matrix contains both magnesium and manganese. Manganese acts as a reinforcing agent, ensuring the ultimate tensile strength of the composite material while reducing the magnesium content. Simultaneously, manganese promotes the uniform precipitation of Mg5Al8 compounds, improving the corrosion resistance and weldability of the composite material. However, if the manganese content is too high, its effect on improving the elongation of the composite material is not significant, leading to increased costs. Therefore, this application limits the mass of manganese to less than or equal to 0.8% of the matrix mass.
[0038] In one possible design, the composite material satisfies at least one of the following three conditions: the density of the composite material is less than or equal to 4 g / cm3, the Vickers hardness of the composite material is greater than or equal to 130 HV, and the elastic modulus of the composite material is greater than or equal to 100 GPa.
[0039] In this application, the density of the composite material is less than or equal to 4 g / cm3, the Vickers hardness of the composite material is greater than or equal to 130 HV, and the elastic modulus of the composite material is greater than or equal to 100 GPa, which gives the composite material the advantages of being lightweight, thin, high-strength, and having strong resistance to annealing softening.
[0040] In one possible design, the composite material also includes graphene dispersed within the matrix; the mass of the graphene is G3, and G3 satisfies: G3 / (G1+G2+G3)≤0.5%.
[0041] In this application, the high strength and high modulus properties of graphene can effectively transfer loads, thereby increasing the tensile strength, yield strength, and hardness of the composite material. Appropriate amounts of graphene can promote the optimization of the microstructure within the alloy matrix, such as refining grains or inhibiting crack propagation, which helps improve the toughness and fatigue resistance of the composite material. Graphene possesses extremely high electron mobility and good thermal conductivity, thus significantly enhancing the electrical and thermal conductivity of the composite material. Graphene can reduce the overall density of the composite material without sacrificing mechanical properties, thereby achieving weight reduction. Graphene's hydrophobicity and chemical inertness allow it to form a protective barrier, preventing moisture and other corrosive media from contacting the alloy matrix, thereby improving the corrosion resistance of the composite material. Graphene can also improve the processability of the composite material, reducing internal stress during the molding process and thus lowering the risk of cracking during processing.
[0042] If the graphene content is too high, the high concentration of graphene may weaken the interfacial bonding force between the graphene and the alloy matrix. Under external force, cracks or delamination may easily form at the interface, thus affecting the strength and toughness of the composite material. Excessive graphene may cause embrittlement of the composite material, that is, a decrease in the ductility and impact toughness of the composite material, making it more prone to fracture. Therefore, a graphene content of no more than 0.5% can improve the strength, toughness, and ductility of the composite material.
[0043] In one possible design, the graphene is redox graphene.
[0044] In this application, redox graphene is used, which is beneficial to improving the dispersion uniformity of graphene in the alloy matrix and to enhancing the electrical conductivity, thermal conductivity, strength and toughness of the composite material.
[0045] In one possible design, the yield strength of the composite material is greater than or equal to 300 MPa.
[0046] In this application, the yield strength of the composite material is greater than or equal to 300 MPa, which further improves the strength of the plate and reduces its weight.
[0047] In one possible design, the plate is a medium plate with a thickness of 0.1mm-3mm.
[0048] In this application, the plate used as the middle plate can form the middle frame assembly of the electronic device together with the frame. When the plate is a middle plate used to support the electronic components inside the electronic device, the whole or the main load-bearing parts of the plate can be made of the above-mentioned composite material to increase the load-bearing capacity of the plate and the middle frame assembly, while reducing the weight of the plate, so as to realize the lightweight design of the electronic device.
[0049] In one possible design, the plate is a heat dissipation plate, which includes a first substrate, a second substrate, and a capillary structure. The first substrate and the second substrate form a heat dissipation cavity, and the capillary structure is located inside the heat dissipation cavity and connected to the first substrate. The first substrate is made of composite material and has a thickness of 0.1 mm to 0.3 mm.
[0050] In this application, the plate used as a heat spreader can be mounted on the plate of the middle frame assembly. Alternatively, the plate used as a heat spreader can be directly mounted on the frame instead of the plate, thereby reducing the overall thickness of the housing assembly. The first substrate is the main load-bearing component; the first substrate is made of composite material, which enhances its load-bearing capacity and facilitates a thinner, lighter design.
[0051] In one possible design, the material of the second substrate is polyimide; or, the material of the second substrate is a composite material, and the thickness of the second substrate is 0.03mm-0.15mm.
[0052] In this application, the second substrate is made of polyimide, which can reduce the overall weight of the board. The second substrate is made of the aforementioned composite material, which reduces the weight of the second substrate while improving its load-bearing capacity, thereby achieving simultaneous optimization of the load-bearing capacity and weight of the board.
[0053] In one possible design, the first substrate has a first surface and the second substrate has a second surface. Along the thickness direction of the board, the first surface is located on the side of the first substrate closer to the second substrate, and the second surface is located on the surface of the second substrate closer to the first substrate. The board also includes a first metal layer and a second metal layer. The first metal layer is disposed on the first surface and the second metal layer is disposed on the second surface. The first metal layer and the second metal layer are welded and fixed, or the first metal layer and the second metal layer are bonded and fixed.
[0054] In this application, the first substrate and the second substrate are sealed and fixed together by a composite metal layer, which reduces the difficulty of sealing the first substrate and the second substrate, thereby helping to shorten the processing cycle of the board.
[0055] In one possible design, the thickness of the first metal layer is 7μm-20μm, and the thickness of the second metal layer is 7μm-20μm.
[0056] In this application, the thickness of the first metal layer and the second metal layer is 7μm-20μm, which can simultaneously reduce the processing difficulty and processing cost of the first plate and the second plate.
[0057] In one possible design, the first substrate has a third surface and the second substrate has a fourth surface. Along the thickness direction of the board, the third surface is located on the side of the first substrate away from the second substrate, and the fourth surface is located on the side of the second substrate away from the first substrate. The board also includes a third metal layer and a fourth metal layer, with the third metal layer disposed on the third surface and the fourth metal layer disposed on the fourth surface.
[0058] In this application, a third metal layer is covered on the outer side of the first substrate and a fourth metal layer is covered on the outer side of the second substrate, which can improve the thermal conductivity of the first and second substrates, thereby improving the heat dissipation performance of the substrates and electronic devices.
[0059] This application provides a housing assembly comprising the composite material described in any of the above claims.
[0060] In this application, the composite material has the advantages of being lightweight, thin, high-strength, and having strong resistance to annealing softening. At least part of the shell assembly is made of the composite material, which is beneficial to achieving a lightweight design of the shell assembly.
[0061] This application provides a housing assembly, which includes: a frame and a plate as described in any of the above claims, wherein the plate is fixedly connected to the frame or integrally formed.
[0062] In this application, the plate has the advantages of being lightweight, thin, high-strength, and having strong resistance to annealing softening, which is conducive to realizing the lightweight design of the shell assembly.
[0063] This application provides an electronic device comprising the composite material described in any of the above claims.
[0064] In this application, the composite material has the advantages of being lightweight, thin, high-strength, and having strong resistance to annealing softening. At least a part of the electronic device is made of the composite material, which is beneficial to realizing the lightweight design of the electronic device.
[0065] This application provides an electronic device that includes the plate body described in any of the above claims.
[0066] In this application, the board has the advantages of being lightweight and thin, having high strength, and being resistant to annealing softening, which is conducive to realizing the lightweight design of electronic devices with this board.
[0067] This application provides an electronic device, which includes: the aforementioned housing assembly and a display screen, wherein the display screen is mounted on the housing assembly.
[0068] In this application, the board body has the advantages of being thin and light, having high strength, and strong resistance to annealing softening, which is conducive to realizing the lightweight design of electronic devices.
[0069] In one possible design, the plate is a middle plate.
[0070] In this application, the plate used as the middle plate can form the middle frame assembly of the electronic device together with the frame. Since the plate has the advantage of high strength, the support stability of the plate and the middle frame assembly for the electronic components inside the electronic device is improved, which in turn helps to improve the working stability of the electronic components.
[0071] In one possible design, the plate is a heat spreader.
[0072] In this application, the plate used as a heat spreader enables rapid heat transfer from the heat-generating element (i.e., a high-temperature electronic component), thereby improving the heat dissipation efficiency of the heat-generating element. The plate used as a heat spreader can be mounted on the plate of the mid-frame assembly. Alternatively, the plate used as a heat spreader can be directly mounted on the frame instead of the plate, thereby reducing the overall thickness of the housing assembly.
[0073] The fifth aspect of this application provides a method for preparing a composite material, the method comprising: taking aluminum particles, magnesium particles, silicon particles, copper particles and manganese particles, and preparing a matrix according to a first preset ratio; preparing the matrix into a matrix powder; taking silicon carbide powder, and mixing the matrix powder and silicon carbide powder according to a second preset ratio to form a composite powder; preparing the composite powder into a composite plate with a second preset thickness, wherein, in the composite plate, the mass of silicon carbide is G1, and the sum of the masses of aluminum, magnesium, silicon, copper and manganese is G2, and G1 and G2 satisfy: 20% ≤ G1 / (G1+G2) ≤ 40%, 60% ≤ G2 / (G1+G2) ≤ 80%.
[0074] In this application, silicon carbide possesses extremely high elastic modulus, hardness, chemical inertness, excellent high-temperature performance, good thermal conductivity, and a low coefficient of thermal expansion. Dispersing silicon carbide on an Al-Mg-Si-Cu-Mn alloy matrix significantly improves the composite material's strength, hardness, elastic modulus, wear resistance, heat resistance, thermal stability, thermal conductivity, and corrosion resistance. It also reduces the degree of dimensional and shape changes in the composite material due to temperature variations, thereby improving the structural stability of the plate made from the composite material. Simultaneously, while maintaining high strength, silicon carbide is lighter than some traditional reinforcing materials (alumina, titanium carbide, etc.), which is beneficial for achieving lightweight designs of plates and electronic devices.
[0075] Manganese can play a role in solid solution strengthening and grain refinement, thereby improving the strength, hardness, low-temperature toughness, corrosion resistance, yield strength and hardness of composite materials.
[0076] If the silicon carbide content is below 20%, its effect on improving the elastic modulus of the composite material is poor; if the silicon carbide content is above 40%, it will lead to excessive brittleness in the composite material, posing a risk of cracking or even breakage during subsequent processing. Therefore, a silicon carbide content of 20%-40% can improve the elastic modulus of the composite material and plate, and reduce the risk of cracking and damage during processing.
[0077] In one possible design, the mass of the matrix is G2, and the first preset proportions satisfy: the mass of magnesium g1 satisfies: 0.5% ≤ g1 / G2 ≤ 1.2%; the mass of silicon g2 satisfies: 0.5% ≤ g2 / G2 ≤ 1.0%; the mass of copper g3 satisfies: 0.4% ≤ g3 / G2 ≤ 1.6%; the mass of manganese g4 satisfies: 0 < g4 / G2 ≤ 0.8%; and the mass of aluminum g5 satisfies: 95.4% ≤ g5 / G2 < 98.6%.
[0078] In this application, magnesium can improve the ultimate tensile strength and yield strength of composite materials. If the mass fraction of magnesium is low, the ultimate tensile strength and yield strength of composite materials and plates will decrease. On the other hand, excessive magnesium content will increase the brittleness of composite materials, which is not conducive to the subsequent processing of composite materials. Therefore, the mass of magnesium needs to be limited to 0.5%-1.2% of the matrix mass.
[0079] Silicon can form a reinforcing phase with magnesium to improve the yield strength and hardness of composite materials. However, excessive silicon content will reduce the elongation of the composite material. Therefore, the mass of silicon needs to be limited to 0.5%-1.0% of the matrix mass.
[0080] Copper has a certain solid solution strengthening effect, which can significantly improve the fluidity, ultimate tensile strength and hardness of composite materials. If the copper content is high, it will reduce the plasticity of the composite material and increase the risk of cracking during the later molding process. Therefore, the mass of copper should be limited to 0.4%-1.6% of the matrix mass.
[0081] The matrix contains both magnesium and manganese. Manganese acts as a reinforcing agent, reducing the magnesium content while ensuring the ultimate tensile strength of the composite material. Simultaneously, manganese promotes the uniform precipitation of Mg5Al8 compounds, improving the corrosion resistance and weldability of the composite. The elongation of the composite reaches its maximum when the manganese content is 0.8%. If the manganese content exceeds 0.8%, its effect on improving the elongation is not significant, leading to increased costs. Therefore, the mass of manganese must be limited to less than or equal to 0.8% of the matrix mass.
[0082] In one possible design, the median particle size of silicon carbide is 0.5 μm-3 μm; the median particle size of the matrix powder is 2 μm-20 μm.
[0083] In this application, the median particle size of silicon carbide is controlled at 0.5μm-3μm and the median particle size of the matrix powder is controlled at 2μm-20μm. This can reduce the ball milling speed in the subsequent ball mill, thereby reducing the energy consumption of the ball mill, and also helps to improve the mixing uniformity of silicon carbide in the matrix powder, so as to improve the performance of the composite material.
[0084] In one possible design, the step of mixing the matrix powder and silicon carbide powder in a second preset ratio to form a composite powder includes: taking graphene powder, and mixing the graphene powder, matrix powder, and silicon carbide powder in a ball mill in a third preset ratio to form a composite powder. The ball mill speed is 30 r / min-60 r / min, the ball milling time is 18 h-25 h, and the ball-to-powder ratio is 1:1 to 3:1. The third preset ratio satisfies the following conditions: the mass of silicon carbide is G1, the mass of the matrix is G2, the mass of graphene powder is G3, and G3 / (G1+G2+G3)≤0.5%.
[0085] In this application, powder metallurgy is used to prepare composite materials, which improves the control precision of the content of graphene, silicon carbide and matrix, thereby facilitating the adjustment of the mechanical properties of composite materials. At the same time, it reduces the energy consumption in the composite material preparation process, thereby reducing the preparation cost of composite materials. In addition, it can also increase the mixing uniformity of graphene in the matrix, so as to further improve the mechanical properties of composite materials.
[0086] If the ball mill speed is less than 30 r / min, the mixing efficiency of the silicon carbide powder and matrix powder is low, and the slow speed affects the uniformity of silicon carbide mixing in the matrix, thus impacting the mechanical properties of the composite material (e.g., strength, toughness, elongation). Since the median particle size of both silicon carbide and matrix powders is small, a ball mill speed of 30-60 r / min is sufficient for uniform mixing. Speeds exceeding 60 r / min lead to excessive energy consumption, increasing the cost of the composite material. Therefore, a ball mill speed of 30-60 r / min improves mixing efficiency and uniformity, thereby enhancing the mechanical properties of the composite material while reducing energy consumption and cost.
[0087] In one possible design, the step of forming a composite plate with a second preset thickness from the composite powder includes: forming a thick plate with a first preset thickness of 3mm-10mm from the composite powder; and performing surface removal of the oxide layer and multiple rolling, annealing, polishing and trimming processes on the thick plate to form a composite plate with a second preset thickness of 0.1mm-3mm from the thick plate.
[0088] In this application, a thick plate is prepared first, and then a thin plate is prepared. This reduces the processing difficulty of the plate and the risk of uneven thickness and cracking of the thin plate caused by direct processing, thereby improving the processing yield of the plate.
[0089] In one possible design, after the step of forming a composite plate with a second preset thickness from the composite powder, the method for preparing the composite material includes: performing a solution treatment and an aging treatment on the composite plate, wherein the solution treatment temperature is 400℃-600℃ and the solution treatment time is 20min-40min; and the aging treatment temperature is 150℃-250℃ and the aging treatment time is 7h-12h.
[0090] In this application, solution treatment and aging treatment of the composite material can improve its strength, processability, hardness, and elongation. In this embodiment, the aging treatment time is 7-12 hours, allowing the composite material to reach its optimal strength and hardness. This state allows the mechanical properties of the composite material (such as yield strength, ultimate tensile strength, etc.) to approach or even reach their optimal values, thereby improving the mechanical properties of the composite material.
[0091] In one possible design, after the step of forming a composite plate with a second predetermined thickness from the composite powder, the method for preparing the composite material includes: leveling the composite plate by tension.
[0092] In this application, the composite board is straightened and leveled, which can improve the board shape and facilitate subsequent processing of the composite board. Attached Figure Description
[0093] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0094] Figure 1 is a schematic diagram of the structure of the electronic device provided in this application in one embodiment;
[0095] Figure 2 is a schematic diagram of the housing assembly in some embodiments;
[0096] Figure 3 is a partial structural cross-sectional view of the housing assembly in some embodiments;
[0097] Figure 4 is a partial structural cross-sectional view along direction AA in Figure 2;
[0098] Figure 5 is a partial structural cross-sectional view along the BB direction in Figure 2;
[0099] Figure 6 is a structural schematic diagram of the housing assembly in some other embodiments;
[0100] Figure 7 is a schematic diagram of the heat spreader in Figure 6;
[0101] Figure 8 is a cross-sectional view of the heat spreader in one embodiment;
[0102] Figure 9 is a cross-sectional view of the heat spreader in another embodiment;
[0103] Figure 10 is a cross-sectional view of the heat spreader in another embodiment;
[0104] Figure 11 is a cross-sectional view of a partial structure of the composite material in one embodiment;
[0105] Figure 12 shows the scanning electron microscope (SEM) image of the composite material in Figure 11;
[0106] Figure 13 is a cross-sectional view of a partial structure of the composite material in another embodiment;
[0107] Figure 14 shows the Raman spectrum of the composite material in Figure 13.
[0108] Reference numerals: 01-Shell assembly; 011-Frame; 012-Cover plate; 013-Middle plate; 013-Fastener; 014-Adhesive; 015-Heat spreader; 02-Heating element; 03-Matrix; 04-Reinforcing phase; 05-Graphene; 1-First plate; 11-First substrate; 111-First surface; 112-Third surface; 12-First metal layer; 13-Third metal layer; 2-Second plate; 21-Second substrate; 211-Second surface; 212-Fourth surface; 22-Second metal layer; 23-Fourth metal layer; 3-Heat dissipation cavity; 31-Evaporation zone; 32-Condensation zone; 4-Capillary structure. Detailed Implementation
[0109] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.
[0110] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.
[0111] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.
[0112] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.
[0113] This application provides an electronic device, which can be a mobile phone, tablet, computer, or other devices. This application does not specifically limit the specific type or structure of the electronic device. Figure 1 is a schematic diagram of the electronic device in one embodiment, with a mobile phone as an example. As shown in Figure 1, the electronic device includes a housing assembly 01 and a display screen. The display screen is mounted on the housing assembly 01. The housing assembly 01 includes a frame 011 and a cover plate 012. Along the thickness direction X of the electronic device, both sides of the frame 011 are connected to the display screen and the cover plate 012, respectively. A portion of the frame 011, the display screen, and the cover plate 012 form an internal mounting cavity for the electronic device, facilitating the installation of electronic components such as batteries and chips.
[0114] Figure 2 is a schematic diagram of the housing assembly in some embodiments. As shown in Figure 2, the housing assembly 01 also includes a middle plate 013 mounted on the frame 011. The middle plate 013 and the frame 011 form the middle frame assembly of the electronic device. Figure 3 is a partial structural cross-sectional view of the housing assembly in Figure 2 in some embodiments. As shown in Figure 3, the middle plate 013 is located in the mounting cavity and is used to support and fix electronic components such as batteries and chips in the mounting cavity. In one embodiment, the connection between the middle plate 013 and the frame 011 can be at least one of bonding, welding, riveting, interference fit, and fastener fixing. Fasteners include, but are not limited to, screws, bolts, pins, etc. The embodiments of this application do not impose special limitations on the fixing form and structure of the frame 011 and the middle plate 013. In other embodiments, the frame and the middle plate can also be integrally formed.
[0115] Figure 4 is a structural diagram of the middle plate 013 and the frame 011 fixedly connected by fastener 013. As shown in Figure 4, the middle plate 013 is fixed to the frame 011 by fastener 013, which simplifies the connection between the middle plate 013 and the frame 011, thereby helping to shorten the assembly cycle of the housing assembly, and thus helping to shorten the assembly cycle of electronic devices and improve the production efficiency of electronic devices.
[0116] Figure 5 is a schematic diagram of the structure when the middle plate 013 is bonded and fixed to the frame 011. As shown in Figure 5, the middle plate 013 is bonded and fixed to the frame 011 by the adhesive 014, which reduces the space occupied by the installation cavity of the middle plate 013 and the frame 011, thereby improving the utilization rate of the installation cavity of the electronic device, thereby improving the integration of the electronic device and improving the function of the electronic device.
[0117] The middle plate 013 and the frame 011 can be connected using the connection methods shown in Figures 4 and 5. That is, during the assembly of the housing assembly 01, the middle plate 013 and the frame 011 can be pre-fixed using the adhesive 014, and then the middle plate 013 and the frame 011 can be finally fixed using the fasteners 013 in Figure 4. This reduces the risk of the plate 013 or the frame 011 moving or deflecting during the process of locking the fasteners 013, thereby improving the accuracy of the relative position of the middle plate 013 and the frame 011 during the installation process. This, in turn, helps to improve the accuracy of the assembly of the housing assembly 01 and the assembly yield of the housing assembly 01.
[0118] Figure 6 is a structural schematic diagram of the housing assembly in some other embodiments. As shown in Figure 6, in some embodiments, the housing assembly may further include a heat spreader 015 located within the mounting cavity. The heat spreader 015 can dissipate heat from the electronic components inside the electronic device to reduce the temperature of these electronic components, thereby improving the performance of the electronic device.
[0119] Figure 7 is a partial structural schematic diagram of the heat spreader 015, and Figure 8 is a cross-sectional view of the heat spreader 015 in some embodiments. As shown in Figures 7 and 8, the heat spreader 015 includes a first substrate 11 and a second substrate 21 distributed along the thickness direction X. The first substrate 11 and the second substrate 21 form a heat dissipation cavity 3. A capillary structure 4 is disposed in the heat dissipation cavity 3. The capillary structure 4 is processed on the first substrate 11, that is, the capillary structure 4 is integrally formed with the first substrate 11. Alternatively, the capillary structure 4 is fixed on the first substrate 11. The capillary structure 4 can be a metal mesh, metal fiber, or metal powder, etc. The material of the capillary structure 4 can be a metal such as copper or aluminum. In the embodiments of this application, the capillary structure 4 is a copper mesh, copper fiber, or copper powder.
[0120] As shown in Figure 8, the heat dissipation cavity 3 includes an evaporation zone 31 and a condensation zone 32 distributed along the thickness direction X. The region within the heat dissipation cavity 3 containing the capillary structure 4 and a liquid heat exchange medium (not shown in the figure) is defined as the evaporation zone 31. Within the evaporation zone 31, the liquid heat exchange medium evaporates when heated. The region within the heat dissipation cavity 3 excluding the evaporation zone 31 is defined as the condensation zone 32. Within the condensation zone 32, the heat exchange medium evaporated into a gaseous state can condense into a liquid heat exchange medium. It should be noted that the embodiments of this application do not specifically limit the shape, size, and relative position of the evaporation zone 31 and the condensation zone 32. In the embodiment shown in Figure 8, along the thickness direction X, the evaporation zone 31 is located below the condensation zone 32.
[0121] In other embodiments, the capillary structure 4 may also be fabricated on the second substrate 21, or the capillary structure 4 may also be fixed on the second substrate 21. The following description takes the example of the capillary structure 4 being fabricated on the first substrate 11 or fixed on the first substrate 11.
[0122] The first substrate 11 is used to contact the electronic components inside the electronic device. When the electronic device is working, electronic components such as batteries or chips will generate heat. The heated electronic components are referred to as heating elements. As shown in Figure 8, when the temperature of the heating element 02 in contact with the first substrate 11 rises, the temperature of the liquid heat exchange medium in the evaporation zone 31 rises. At least part of the liquid heat exchange medium evaporates into a gaseous heat exchange medium and enters the condensation zone 32. The gaseous heat exchange medium contacts the second substrate 21 in the condensation zone 32. The gaseous heat exchange medium exchanges heat with the low-temperature air outside through the second substrate 21, causing the temperature of the gaseous heat exchange medium to drop and re-condense into a liquid heat exchange medium. The liquid heat exchange medium falls back into the evaporation zone 31 under the total force of gravity.
[0123] By setting the capillary structure 4, the liquid heat exchange medium can rise or diffuse in the small channels of the capillary structure 4, which increases the surface area of the liquid heat exchange medium in contact with the air and can increase the evaporation rate of the liquid heat exchange medium, thereby improving the heat dissipation performance of the heat spreader 015 and electronic equipment.
[0124] Since the heat dissipation cavity 3 contains a liquid heat exchange medium, the first substrate 11 and the second substrate 21 need to be sealed together. In one embodiment, as shown in FIG8, the first substrate 11 and the second substrate 12 are directly connected to simplify the structure of the heat spreader 015 and to reduce the weight of the heat spreader 015, so as to meet the lightweight requirements of electronic devices.
[0125] In this embodiment, at least one of the inner and outer surfaces of the first substrate 11 and the second substrate 21 is covered with a metal layer.
[0126] Figure 9 is a cross-sectional view of the heat spreader in some embodiments. In some embodiments, as shown in Figure 9, along the thickness direction X, the surface of the first substrate 11 near the second substrate 21 is designated as the first surface 111, and the surface of the second substrate 21 near the first substrate 11 is designated as the second surface 211. A first metal layer 12 is laminated on the first surface 111 to form a first plate body 1, that is, the first plate body 1 is a composite plate composed of the first substrate 11 and the first metal layer 12. The first metal layer 12 can be formed on the first surface 111 by processes such as rolling lamination, explosive lamination, and electroplating. A second metal layer is laminated on the second surface 211 to form a second plate body 2, that is, the second plate body 2 is a composite plate composed of the second substrate 21 and the second metal layer 22. The second metal layer 22 can be formed on the first surface 211 by processes such as rolling lamination, explosive lamination, and electroplating. The first metal layer 12 and the second metal layer 22 are fixedly connected by processes such as diffusion welding and bonding to achieve sealing and fixing of the first substrate 11 and the second substrate 21.
[0127] In this embodiment, the first substrate 11 and the second substrate 21 are sealed and fixed by a composite metal layer, which reduces the sealing difficulty of the first substrate 11 and the second substrate 21, thereby helping to shorten the processing cycle of the heat spreader.
[0128] Figure 10 is a cross-sectional view of the vapor chamber in some other embodiments. As shown in Figure 10, along the thickness direction X, the surface of the first substrate 11 facing away from the second substrate 21 is designated as the third surface 112. Unlike the embodiment shown in Figure 9, the third surface 112 is laminated with a third metal layer 13, meaning the first plate 1 is a composite plate composed of the first substrate 11, the first metal layer 12, and the third metal layer 13. As shown in Figure 10, the surface of the second substrate 21 facing away from the first substrate 11 is designated as the fourth surface 212. Unlike the embodiment shown in Figure 9, the fourth surface 212 is laminated with a fourth metal layer 23, meaning the second plate 2 is a composite plate composed of the second substrate 21, the second metal layer 22, and the fourth metal layer 23.
[0129] In this embodiment, a third metal layer 13 is covered on the outside of the first substrate 11 and a fourth metal layer 23 is covered on the outside of the second substrate 21, which can further improve the thermal conductivity of the first plate 1 and the second plate 2, thereby improving the heat dissipation performance of the heat dissipation plate and the electronic device having the heat dissipation plate.
[0130] The heat spreader may have only one of the first metal layer 12, the second metal layer 22, the third metal layer 13 and the fourth metal layer 23, or it may have at least two of the first metal layer 12, the second metal layer 22, the third metal layer 13 and the fourth metal layer 23.
[0131] The first metal layer 12, the second metal layer 22, the third metal layer 13, and the fourth metal layer 23 can be made of metals such as gold, silver, copper, and aluminum. The materials of the first metal layer 12, the second metal layer 22, the third metal layer 13, and the fourth metal layer 23 can be the same or different. In this embodiment, the first metal layer 12, the second metal layer 22, the third metal layer 13, and the fourth metal layer 23 are all copper layers to reduce the cost of the heat spreader.
[0132] The thickness of the first metal layer 12 is 7μm-20μm, specifically 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, etc. If the thickness of the first metal layer 12 is less than 7μm, the fabrication difficulty of the first metal layer 12 increases; if the thickness of the first metal layer 12 is greater than 20μm, the processing cost of the first plate 1 increases. Therefore, a thickness of 7μm-20μm for the first metal layer 12 can simultaneously reduce both the processing difficulty and processing cost of the first plate 1.
[0133] The thickness of the second metal layer 22 is 7μm-20μm, specifically 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, etc., which can simultaneously reduce the processing difficulty and processing cost of the second plate 2.
[0134] Similarly, the thickness of the third metal layer 13 is 7μm-20μm, specifically 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, etc. The thickness of the fourth metal layer 23 is 7μm-20μm, specifically 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, etc.
[0135] The thicknesses of the first metal layer 12, the second metal layer 22, the third metal layer 13, and the fourth metal layer 23 can be the same or different.
[0136] Based on the aforementioned heat spreader, in some embodiments, the housing assembly has both a heat spreader and a middle plate, with the heat spreader fixed to the middle plate, i.e., the heat spreader is fixed to the middle plate of the electronic device's frame assembly. In other embodiments, the housing assembly only has a heat spreader, which is fixed to the frame. In this case, the heat spreader replaces the middle plate. The heat spreader can support some of the electronic components within the mounting cavity and simultaneously dissipate heat from the supported electronic components. Using a heat spreader instead of a middle plate helps reduce the overall thickness of the housing assembly and the electronic device.
[0137] To meet the lightweight design requirements of electronic devices, existing electronic devices typically use at least a portion of the middle plate made of 0.4mm thick aluminum alloy, stainless steel, or copper alloy, and the first substrate of the heat spreader is also made of 0.4mm thick aluminum alloy, stainless steel, or copper alloy. However, the middle plate and heat spreader made of aluminum alloy, stainless steel, or copper alloy cannot simultaneously meet the requirements of high yield strength and thinness. Among known materials, Al-Mg-Si-Cu alloys have high hardness and light weight, and are widely used in electronic devices. Al-Mg-Si-Cu alloys improve yield strength by precipitating coherent / semi-coherent Mg2Si or Cu-rich phases, resulting in high material hardness. However, during subsequent high-temperature processing, high-temperature forming, and high-temperature welding, the coherent / semi-coherent Mg2Si or Cu-rich phases grow into incoherent coarse phases, causing a sharp drop in yield strength. Consequently, Al-Mg-Si-Cu alloys undergo annealing softening during high-temperature processes, resulting in a decrease in both yield strength and hardness, failing to meet the requirements.
[0138] In view of this, embodiments of this application provide a composite material, in which at least a portion of the structure of the housing assembly of an electronic device can be made of the composite material. For example, at least a portion of the plate body can be made of the composite material, and the plate body can be used as at least one of the frame, cover plate, middle plate, and heat spreader of the housing assembly. Compared with aluminum alloy, stainless steel, or copper alloy, the composite material provided in this application embodiment has a lower density (less than or equal to 4 g / cm3), a higher Vickers hardness (greater than or equal to 130 HV), and a higher elastic modulus (greater than or equal to 100 GPa), that is, the composite material has the advantages of being lightweight, thin, high-strength, and having strong resistance to annealing softening. Compared with existing materials, the housing assembly made of this composite material also has the advantages of being lightweight, thin, high-strength, and having strong resistance to annealing softening, and can simultaneously meet the requirements of high yield strength and thinness, thereby strengthening the reliability of the plate body in supporting electronic components, improving the overall structural stability of the electronic device, and at the same time, helping to reduce the weight of the electronic device and realize the lightweight design of the electronic device. The composition of the composite material is described in detail below.
[0139] Figure 11 is a schematic diagram of a partial structure of the composite material. As shown in Figure 11, the composite material includes a matrix 03 and a reinforcing phase 04, with the reinforcing phase 04 dispersed within the matrix 03. Figure 12 is a scanning electron microscope (SEM) image of the composite material. The darker areas in Figure 12 represent the reinforcing phase 04, and the lighter areas represent the matrix 03. The matrix 03 includes aluminum, magnesium, silicon, copper, and manganese. The reinforcing phase 04 can be silicon carbide, alumina, titanium carbide, titanium boride, titanium carbide, boron carbide, carbon fiber, carbon nanotubes, graphene, etc. In this embodiment, the reinforcing phase 04 is silicon carbide.
[0140] In this embodiment, silicon carbide possesses extremely high elastic modulus, hardness, chemical inertness, excellent high-temperature performance, good thermal conductivity, and a low coefficient of thermal expansion. Dispersing silicon carbide on an Al-Mg-Si-Cu-Mn alloy matrix significantly improves the composite material's elastic modulus, strength, hardness, wear resistance, heat resistance, thermal stability, and thermal conductivity. It also reduces the degree of dimensional and shape changes in the composite material caused by temperature variations, improving the structural stability of the plate containing this composite material. This enhances the support stability of the plate for electronic components, thereby improving the operational stability of the electronic components. When the temperature of a heat-generating element in contact with the plate rises, the plate containing this composite material enables rapid heat transfer, thus improving the heat dissipation efficiency of the heat-generating element. Simultaneously, while maintaining high strength, silicon carbide is lighter than some traditional reinforcing materials (alumina, titanium carbide, etc.), facilitating the design of thinner and lighter plates, which in turn contributes to the lightweight design of electronic devices including this plate.
[0141] Manganese plays a role in both solid solution strengthening and grain refinement. Solid solution strengthening refers to the fact that when manganese (solute atoms) is added to the alloy matrix (solvent), it occupies normal lattice positions. This means manganese can enter the crystal structure as substitutional solute atoms, causing lattice distortion and hindering dislocation movement of solvent atoms, thereby improving the strength, hardness, low-temperature toughness, and corrosion resistance of the composite material. Grain refinement strengthening refers to the fact that during the hot working of the composite material or plates containing it, manganese can reduce or even prevent annealing softening caused by the growth of coherent / semi-coherent Mg₂Si or Cu-rich phases, thus improving the yield strength and hardness of the composite material or plates containing it. Compared to traditional aluminum alloys, the strengthening precipitates (coherent / semi-coherent Mg2Si or Cu-rich precipitates) will grow into incoherent coarse phases during subsequent hot working (such as 250℃), resulting in a sharp decrease in yield strength, which is the so-called annealing softening phenomenon. However, the solid solution strengthening and grain refinement strengthening capabilities of manganese will not be reduced by subsequent heating, thus improving the annealing softening resistance of composite materials.
[0142] In some embodiments, the mass of the reinforcing phase is G1, and the mass of the matrix is G2, wherein G1 and G2 satisfy: 20% ≤ G1 / (G1+G2) ≤ 40%, and 60% ≤ G2 / (G1+G2) ≤ 80%. For example, in some embodiments, the mass fraction of silicon carbide can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, etc.
[0143] In this embodiment, if the silicon carbide content is too low, the effect of silicon carbide on improving the elastic modulus of the composite material is poor; if the silicon carbide content is too high, it will lead to excessive brittleness of the composite material, posing a risk of cracking or even breakage during subsequent processing. In this embodiment, the silicon carbide content is 20%-40% to improve the elastic modulus of the plate containing the composite material and reduce the risk of cracking or damage to the plate containing the composite material during processing.
[0144] The median particle size D1 of silicon carbide satisfies: 0.5μm ≤ D1 ≤ 3μm. The median particle size is a statistical parameter describing the particle size distribution. It refers to the particle size that corresponds to 50% of the cumulative volume or number of particles on the cumulative particle size distribution curve; that is, half of the particles are smaller than this size, and the other half are larger. For example, in some embodiments, the median particle size of silicon carbide can be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2 μm, 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3 μm, etc.
[0145] In this embodiment, if the median particle size of silicon carbide is too small, it increases the processing difficulty and cost of silicon carbide powder; if the median particle size of silicon carbide powder is too large, the mixing uniformity of silicon carbide in the alloy matrix will decrease. In this embodiment, the median particle size of silicon carbide is 0.5 μm-3 μm, which reduces the cost of silicon carbide powder, thereby reducing the cost of the plate containing the composite material. It also helps improve the mixing uniformity of silicon carbide in the alloy matrix, thus improving the strength, hardness, fatigue resistance, thermal conductivity, and processing performance of the plate containing the composite material.
[0146] The median particle size D2 of the matrix satisfies: 2μm≤D2≤20μm. For example, in some embodiments, the median particle size of the matrix can be 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, etc.
[0147] In this embodiment, if the median particle size of the matrix is too small, it increases the processing difficulty and cost of the matrix; if the median particle size of the matrix is too large, the mixing uniformity of silicon carbide in the alloy matrix will decrease. Furthermore, a matrix with a larger particle size will affect the strength, toughness, and elongation of the composite material. In this embodiment, the median particle size of the matrix is 2μm-20μm, which reduces the cost of the matrix, thereby reducing the cost of the plate containing the composite material. It also helps to improve the mixing uniformity of silicon carbide in the matrix, thus improving the strength, hardness, fatigue resistance, thermal conductivity, and processability of the plate containing the composite material. Simultaneously, a smaller particle size matrix can further improve the strength, toughness, and elongation of the plate containing the composite material.
[0148] In the matrix, the mass of magnesium (g1) satisfies: 0.5% ≤ g1 / G2 ≤ 1.2%; the mass of silicon (g2) satisfies: 0.5% ≤ g2 / G2 ≤ 1.0%; the mass of copper (g3) satisfies: 0.4% ≤ g3 / G2 ≤ 1.6%; the mass of manganese (g4) satisfies: 0 < g4 / G2 ≤ 0.8%; and the mass of aluminum (g5) satisfies: 95.4% ≤ g5 / G2 < 98.6%.
[0149] Magnesium can improve the ultimate tensile strength and yield strength of composite materials. If the mass fraction of magnesium is low, the ultimate tensile strength and yield strength of the composite material and the plate containing the composite material will decrease. On the other hand, excessive magnesium content will increase the brittleness of the composite material, which is not conducive to the subsequent processing of the composite material. Therefore, in this application embodiment, the mass of magnesium is limited to 0.5%-1.2% of the matrix mass.
[0150] Silicon can form a reinforcing phase with magnesium to improve the yield strength and hardness of composite materials. However, excessive silicon content will reduce the elongation of the composite material. Therefore, in this application, the mass of silicon is limited to 0.5%-1.0% of the matrix mass.
[0151] Copper has a certain solid solution strengthening effect, which can significantly improve the fluidity, ultimate tensile strength and hardness of composite materials. If the content of copper is high, it will reduce the plasticity of the composite material and increase the risk of cracking during the later molding process. Therefore, in this application, the mass of copper is limited to 0.4%-1.6% of the matrix mass.
[0152] The matrix contains both magnesium and manganese. Manganese acts as a reinforcing agent, reducing the magnesium content while ensuring the ultimate tensile strength of the composite material. Simultaneously, manganese promotes the uniform precipitation of Mg5Al8 compounds, improving the corrosion resistance and weldability of the composite material. However, if the manganese content is too high, its effect on improving the elongation of the composite material is not significant, leading to increased costs. Therefore, in this application, the mass of manganese is limited to less than or equal to 0.8% of the matrix mass.
[0153] Figure 13 is a schematic diagram of a partial structure of the composite material in some embodiments. As shown in Figure 13, in some embodiments, the composite material may also include graphene 05, which is dispersed in the matrix 03. The high strength and high modulus of graphene 05 can effectively transfer load, thereby increasing the tensile strength, yield strength and hardness of the composite material. For example, after adding graphene 05, the yield strength of the composite material can be greater than or equal to 300 MPa, thereby improving the strength and reducing the weight of the composite material, further improving the strength of the plate containing the composite material and reducing the weight of the plate containing the composite material.
[0154] Appropriate amounts of graphene 05 can promote the optimization of the internal microstructure of the alloy matrix, such as refining grains or inhibiting crack propagation, which helps improve the toughness and fatigue resistance of the composite material. Graphene 05 possesses extremely high electron mobility and good thermal conductivity, thus significantly enhancing the electrical and thermal conductivity of the composite material. Graphene 05 can reduce the overall density of the composite material without sacrificing mechanical properties, thereby achieving weight reduction. The hydrophobicity and chemical inertness of graphene 05 allow it to form a protective barrier, preventing moisture and other corrosive media from contacting the alloy matrix, thereby improving the corrosion resistance of the composite material. Graphene 05 can also improve the processability of the composite material, reducing internal stress during the molding process and thus lowering the risk of cracking during processing.
[0155] The total weight of the matrix and the reinforcing phase is G, and the mass of graphene is G3. G and G3 satisfy: G3 / G≤0.5%.
[0156] In this embodiment, if the graphene content is too high, the high concentration of graphene may weaken the interfacial bonding force between the graphene and the alloy matrix. Under external force, cracks or delamination are easily generated at the interface, thus affecting the strength and toughness of the composite material. Excessive graphene may cause embrittlement of the composite material, that is, a decrease in the ductility and impact toughness of the composite material, making it more prone to fracture. Therefore, in this embodiment, the graphene content is no higher than 0.5%, which can improve the strength, toughness, and ductility of the composite material.
[0157] Graphene includes graphene oxide and reduced graphene oxide. Because reduced graphene oxide possesses good electrical conductivity, high thermal conductivity, strong strength and toughness, and good dispersibility, in this embodiment, graphene can be reduced graphene oxide, which is beneficial for improving the uniformity of graphene dispersion in the alloy matrix and for enhancing the electrical conductivity, thermal conductivity, strength, and toughness of the composite material.
[0158] Figure 14 shows the Raman spectrum of the composite material. As shown in Figure 14, the graphene content is no higher than 0.5%, which allows the graphene to be uniformly dispersed in the alloy matrix.
[0159] The above describes the specific composition of the composite material provided in the embodiments of this application. The preparation method of the composite material is described in detail below.
[0160] The preparation method of composite materials includes the following steps:
[0161] Take aluminum particles, magnesium particles, silicon particles, copper particles, and manganese particles, and prepare a matrix according to a first preset ratio;
[0162] The matrix is prepared into matrix powder;
[0163] Take silicon carbide powder and mix the matrix powder and silicon carbide powder in a second preset ratio to form a composite powder;
[0164] The composite powder is made into a composite plate with a second preset thickness;
[0165] In the composite board, the mass of silicon carbide is G1, and the sum of the masses of aluminum, magnesium, silicon, copper and manganese is G2. G1 and G2 satisfy the following conditions: 20% ≤ G1 / (G1+G2) ≤ 40%, 60% ≤ G2 / (G1+G2) ≤ 80%.
[0166] In this embodiment, silicon carbide possesses extremely high elastic modulus, hardness, chemical inertness, excellent high-temperature performance, good thermal conductivity, and a low coefficient of thermal expansion. Dispersing silicon carbide on an Al-Mg-Si-Cu-Mn alloy matrix significantly improves the composite material's elastic modulus, strength, hardness, wear resistance, heat resistance, thermal stability, and thermal conductivity. It also reduces the degree of dimensional and shape changes in the composite material caused by temperature variations, thereby improving the structural stability of the plate containing this composite material. Simultaneously, while maintaining high strength, silicon carbide is lighter than some traditional reinforcing materials (alumina, titanium carbide, etc.), which is beneficial for achieving lightweight designs of plates containing this composite material, electronic devices containing this composite material, and electronic devices containing this plate.
[0167] In this embodiment, manganese can play a role in solid solution strengthening and grain refinement strengthening, thereby improving the strength, hardness, low-temperature toughness and corrosion resistance of the composite material. Moreover, the solid solution strengthening and grain refinement strengthening capabilities of manganese will not decrease due to subsequent heating, thus improving the resistance to annealing softening of the plate containing the composite material.
[0168] In this embodiment, if the silicon carbide content is too low, the effect of silicon carbide on improving the elastic modulus of the composite material is poor; if the silicon carbide content is too high, it will lead to excessive brittleness of the composite material, posing a risk of cracking or even breakage during subsequent processing. Therefore, the second preset ratio in this embodiment satisfies: 20% ≤ G1 / (G1+G2) ≤ 40%, 60% ≤ G2 / (G1+G2) ≤ 80%, so that the silicon carbide content is 20%-40%, which can improve the elastic modulus of the composite material and the plate containing the composite material, and reduce the risk of cracking and damage of the composite material and the plate containing the composite material during processing.
[0169] The first preset ratio satisfies the following: the mass of magnesium is 0.5%-1.2% of the matrix mass G2, the mass of silicon is 0.5%-1.0% of the matrix mass G2, the mass of copper is 0.4%-1.6% of the matrix mass G2, the mass of manganese is no more than 0.8% of the matrix mass G2, and the remainder is aluminum.
[0170] After the matrix is made into matrix powder through gas atomization, the median particle size of the matrix powder is 2μm-20μm, and the median particle size of the silicon carbide powder is 0.5μm-3μm.
[0171] In this embodiment, controlling the median particle size of silicon carbide powder to 0.5μm-3μm and the median particle size of matrix powder to 2μm-20μm can reduce the ball milling speed in the subsequent ball mill, thereby reducing the energy consumption of the ball mill, and is conducive to improving the mixing uniformity of silicon carbide in the matrix powder, so as to improve the performance of the composite material.
[0172] The specific steps for mixing the matrix powder and silicon carbide powder in a second preset ratio to form a composite powder include:
[0173] The matrix powder and silicon carbide powder are fed into a ball mill at a second preset ratio, and the rotation of the ball mill ensures that the matrix powder and silicon carbide powder are uniformly mixed. The rotation speed of the ball mill is 30 r / min-60 r / min, the ball milling time is 18 h-25 h, and the ball-to-material ratio is 1:1 to 3:1.
[0174] In this embodiment, the ball mill speed can be 30 r / min, 35 r / min, 40 r / min, 45 r / min, 50 r / min, 55 r / min, 60 r / min, etc. If the ball mill speed is too low, the mixing efficiency of the silicon carbide powder and matrix powder will be low, and the slow speed will affect the mixing uniformity of silicon carbide in the matrix, thereby affecting the mechanical properties of the composite material (e.g., strength, toughness, elongation, etc.). Since the median particle size of silicon carbide powder and matrix powder is small, a ball mill speed of 30 r / min to 60 r / min can achieve uniform mixing. If the ball mill speed is too high, the energy consumption will be too high, increasing the cost of the composite material. Therefore, a ball mill speed of 30 r / min to 60 r / min can improve mixing efficiency and mixing uniformity, thereby improving the mechanical properties of the composite material, while reducing energy consumption during the ball milling process and reducing the cost of the composite material.
[0175] The steps of forming a composite sheet with a second predetermined thickness from the composite powder include:
[0176] The composite powder is made into a thick plate with a first preset thickness of 3mm-10mm;
[0177] The thick plate is subjected to surface oxide layer removal and multiple rolling, annealing, polishing and trimming processes to make a composite plate with a second preset thickness of 0.1mm-3mm.
[0178] In this embodiment, the thick plate is prepared first, and then the thin plate is prepared. This reduces the processing difficulty of the plate and the risk of uneven thickness and cracking of the thin plate caused by directly processing the thin plate, thereby improving the processing yield of the plate.
[0179] After the step of forming the composite powder into a composite plate with a second predetermined thickness, the method for preparing the composite material includes:
[0180] The composite board is subjected to solution treatment and aging treatment. The solution treatment temperature is 400℃-600℃. In some embodiments, the solution treatment temperature can be 400℃, 420℃, 440℃, 460℃, 480℃, 500℃, 520℃, 540℃, 560℃, 580℃, 600℃, etc. The solution treatment time is 20min-40min. In some embodiments, the solution treatment time can be 20min, 21min, 22min, 23min, 24min, 25min, 26min, 27min, 28min, 29min, 30min, 31min, 32min. The aging treatment time is 33 min, 34 min, 35 min, 36 min, 37 min, 38 min, 39 min, 40 min, etc.; the aging treatment temperature is 150℃-250℃, and in some embodiments, the aging treatment temperature can be 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, etc.; the aging treatment time is 7h-12h, and in some embodiments, the aging treatment time can be 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h, 10.5h, 11h, 11.5h, 12h, etc.
[0181] Solution treatment refers to heating the composite sheet to a high temperature of 400℃-600℃, which is usually below the solidus of the material but high enough to allow the alloying elements to fully dissolve into the base metal to form a homogeneous solid solution. Then, it is rapidly cooled (quenched), usually with water or oil as the cooling medium, to form a supersaturated solid solution, thereby improving the strength and processing performance of the composite sheet.
[0182] Aging treatment refers to holding the material at a temperature of 150℃-250℃ (lower than the solution treatment temperature) for a period of time. During this process, the supersaturated solid solution decomposes and precipitates fine and uniformly distributed second-phase particles. These particles can effectively hinder dislocation movement, thereby improving the strength and hardness of the composite board.
[0183] Therefore, in this embodiment, solution treatment and aging treatment of the composite material can improve its strength, processability, hardness, and elongation. In this embodiment, the aging treatment time is 7-12 hours, allowing the composite material to reach its optimal strength and hardness. This state allows the mechanical properties of the composite material (such as yield strength and ultimate tensile strength) to approach or even reach their optimal values, thereby improving the mechanical properties of the composite material.
[0184] After the step of forming the composite powder into a composite plate with a second predetermined thickness, the method for preparing the composite material includes:
[0185] Straightening and leveling composite panels can improve their shape, making them easier to process later.
[0186] When the composite material contains graphene, the step of mixing the matrix powder and silicon carbide powder in a ball mill at a second preset ratio to form a composite powder includes:
[0187] Take graphene powder, and put the graphene powder, matrix powder and silicon carbide powder into a ball mill and mix them into composite powder according to a third preset ratio. The third preset ratio satisfies the following: the total weight of matrix powder and silicon carbide powder is G, the mass of graphene powder is G3, and G3 / G≤0.5%.
[0188] In this embodiment, the composite material is prepared by powder metallurgy, which improves the control precision of the content of graphene, silicon carbide and matrix, thereby facilitating the adjustment of the mechanical properties of the composite material. At the same time, it reduces the energy consumption in the composite material preparation process, thereby reducing the preparation cost of the composite material. In addition, it can also increase the mixing uniformity of graphene in the matrix, so as to further improve the mechanical properties of the composite material.
[0189] When the proportion of graphene exceeds the saturation value, the mixing concentration of graphene in the alloy matrix will not change significantly even if the proportion of graphene powder is increased during the ball milling process of mixing graphene powder and alloy matrix particles. This leads to an increase in the cost of the composite material. Furthermore, if the proportion of graphene is too high, graphene that cannot be mixed into the alloy matrix will remain suspended at the top during ball milling, causing a sharp increase in particle concentration and posing a risk of dust explosion during the process. Therefore, in this embodiment, the mass of graphene is no more than 0.5%, which can reduce the cost of the composite material while improving its strength, toughness, and ductility, and also enhance the safety of the composite material processing.
[0190] The plate containing the composite material can be used as at least one of the frame, cover plate, middle plate, and heat exchange plate of the shell assembly.
[0191] Specifically, the entire middle plate or its main load-bearing parts can be made of the aforementioned composite material to increase the load-bearing capacity of the middle plate while reducing its weight, so as to facilitate the lightweight design of electronic devices.
[0192] When the plate is used as a heat spreader as shown in Figures 8, 9 or 10, since the first substrate 11 is the main load-bearing component, the first substrate 11 is made of the above-mentioned composite material to increase the load-bearing capacity of the first substrate 11 and at the same time reduce the weight of the first substrate 11 so as to realize the lightweight design of electronic devices.
[0193] The second substrate 12 can be made of polyimide to reduce the total weight of the heat spreader; or, the second substrate 12 can also be made of the above-mentioned composite material, with a thickness of 0.03mm-0.15mm, which reduces the weight of the second substrate 12 while increasing its load-bearing capacity, thereby achieving simultaneous optimization of the load-bearing capacity and weight of the heat spreader.
[0194] The preparation method of the plate is described in detail below.
[0195] In one specific embodiment, the method for preparing the plate includes:
[0196] Prepare a composite material; wherein the composite material is the composite material described in any of the above embodiments;
[0197] Take a composite board and use it as the first substrate;
[0198] Preparation of a second matrix;
[0199] The first and second substrates are subjected to multiple warm stamping processes.
[0200] The first substrate and the second substrate are connected and fixed together, forming a heat dissipation cavity for the heat dissipation plate.
[0201] In this embodiment, warm stamping of the first substrate and the second substrate can improve the deformation ability of the first substrate and the second substrate during the stamping process, thereby reducing the risk of cracking and damage of the first substrate and the second substrate during the stamping process.
[0202] Before the step of performing multiple hot stamping forming on the first and second substrates, the method for preparing the plate includes:
[0203] A first metal layer is laminated on the first surface of the first substrate, and the thickness of the first metal layer is 7μm-20μm; a second metal layer is laminated on the second surface of the second substrate, and the thickness of the second metal layer is 7μm-20μm.
[0204] The steps for connecting and fixing the first substrate and the second substrate include:
[0205] The first substrate and the second substrate are stacked along their own thickness direction, and the first metal layer and the second metal layer are welded to fix them.
[0206] Before the step of welding and fixing the first and second metal layers, the method for preparing the plate includes:
[0207] Through multiple rolling, annealing, polishing, and trimming processes, the first plate with the first metal layer is formed into a first plate with a third preset thickness. The third preset thickness is 0.1mm-0.3mm. In some embodiments, the third preset thickness can be 0.1mm, 0.105mm, 0.11mm, 0.115mm, 0.12mm, 0.125mm, 0.13mm, 0.135mm, 0.14mm, 0.145mm, 0.15mm, 0.155mm, 0.16mm, 0.165mm, or 0.17mm. 0.175mm, 0.18mm, 0.185mm, 0.19mm, 0.195mm, 0.2mm, 0.205mm, 0.21mm, 0.215mm, 0.22mm, 0.225mm, 0.23mm, 0.235mm, 0.24mm, 0.245mm, 0.25mm, 0.255mm, 0.26mm, 0.265mm, 0.27mm, 0.275mm, 0.28mm, 0.285mm, 0.29mm, 0.295mm, 0.3mm, etc.
[0208] In this embodiment, after the composite metal layer is applied to the surfaces of the first and second substrates, the first and second substrates are thinned in one step. This reduces the overall size of the board, facilitating its installation on electronic devices. Reducing the board's size decreases its footprint in the mounting cavity of the electronic device, thereby increasing the variety and quantity of components within the mounting cavity and improving the integration and performance of the electronic device. If the third preset thickness is too small, there is a risk of cracking in the first board; if the third preset thickness is too large, the overall size of the board becomes too large. Therefore, in this embodiment, the third preset thickness is 0.1mm-0.3mm, which reduces the overall size of the board and lowers the risk of damage to the first board during processing, thus improving the board's processing yield.
[0209] Before the step of performing multiple hot stamping forming on the first and second substrates, the method for preparing the plate includes:
[0210] A third metal layer is laminated on the third surface, with a thickness of 7μm-20μm; a fourth metal layer is laminated on the fourth surface, with a thickness of 7μm-20μm.
[0211] The steps for preparing the second matrix include:
[0212] Take polyimide and use it as a second matrix; or take a composite board and use it as a second matrix.
[0213] The risk of cracking during processing can be further reduced by optimizing the structural features of the sheet material. For example, simplifying the sheet structure, increasing the inner radius (R-angle) at the stretching and bending points, and reducing the stretching height. The risk can also be reduced by optimizing the processing technology. For instance, increasing the stamping temperature of the composite material facilitates deformation, reducing the stamping rate, and minimizing cracking caused by localized plastic instability.
[0214] In summary, in the first embodiment, when the plate is used as a middle plate, the plate preparation method includes:
[0215] A matrix casting rod was prepared by taking aluminum particles, magnesium particles, silicon particles, copper particles and manganese particles. In the matrix casting rod, the weight percentage of magnesium is 0.4%, the weight percentage of silicon is 0.6%, the weight percentage of copper is 1%, the weight percentage of manganese is 0.5%, and the remainder is aluminum.
[0216] The matrix casting rod was made into matrix powder by gas atomization process, and the median particle size of the matrix powder was 15μm;
[0217] Silicon carbide powder and matrix powder were prepared. The median particle size of the silicon carbide powder was 1 μm, the mass of the silicon carbide powder was 30%, and the mass of the matrix powder was 70%. The silicon carbide powder and matrix powder were put into a ball mill and mixed to form a composite powder. The ball mill speed was 40 r / min, the ball milling time was 20 h, and the ball-to-material ratio was 2:1 to achieve uniform dispersion of silicon carbide.
[0218] The mixed powder is made into an ingot by cold pressing, vacuum degassing and hot isostatic pressing.
[0219] The blank is extruded or hot-rolled into a plate with a thickness of 6mm;
[0220] A 6mm thick plate is processed through surface oxide removal and multiple rolling, annealing, polishing and trimming processes to produce a 0.15mm thick composite plate.
[0221] The composite board was subjected to solution treatment (temperature 540℃, time 30min) and aging treatment (temperature 180℃, time 8h);
[0222] The composite board shape was improved by the tension leveling process, resulting in a composite board with a thickness of 0.15mm, an elastic modulus of 130GPa, a yield strength of 400MPa, an elongation of 4%, a density of 2.85g / cm3, and a hardness of 150HV.
[0223] The above-mentioned 0.15mm composite board is formed by multiple hot stamping processes (hot stamping temperature 180~250℃) to produce a board with preset structural features.
[0224] After the plate undergoes a passivation surface treatment process, it is assembled with the frame. The plate and the frame are fixedly connected by dispensing adhesive and fasteners to form the middle frame assembly of the electronic device. The middle frame assembly is then installed and fixed with structures such as heat spreaders and cover plates to finally form the housing assembly of the electronic device.
[0225] In this embodiment, after warm stamping, the hardness of the composite board is still 150HV. That is, the solid solution strengthening and grain refinement strengthening effects of manganese enhance the composite board's resistance to annealing softening, so that the yield strength and hardness of the composite board are not affected after warm stamping at 250°C.
[0226] In the second embodiment, when the plate is used as a heat spreader, the first substrate of the heat spreader is made of the aforementioned composite material, and the second substrate of the heat spreader is made of polyimide, the method for preparing the plate includes:
[0227] A matrix casting rod was prepared by taking aluminum particles, magnesium particles, silicon particles, copper particles and manganese particles. In the matrix casting rod, the weight percentage of magnesium is 0.8%, the weight percentage of silicon is 0.7%, the weight percentage of copper is 1%, the weight percentage of manganese is 0.5%, and the remainder is aluminum.
[0228] The matrix casting rod was made into matrix powder by gas atomization process, and the median particle size of the matrix powder was 20 μm;
[0229] Silicon carbide powder and matrix powder were prepared. The median particle size of the silicon carbide powder was 2 μm, the mass of the silicon carbide powder was 25%, and the mass of the matrix powder was 75%. The silicon carbide powder and matrix powder were put into a ball mill and mixed to form a composite powder. The ball mill speed was 40 r / min, the ball milling time was 20 h, and the ball-to-powder ratio was 2:1 to achieve uniform dispersion of silicon carbide.
[0230] The mixed powder is made into an ingot by cold pressing, vacuum degassing and hot isostatic pressing.
[0231] The blank is extruded or hot-rolled into a plate with a thickness of 6mm;
[0232] A 6mm thick plate is processed through surface oxide removal and multiple rolling, annealing, polishing and trimming processes to produce a 2mm thick composite plate.
[0233] The composite board was subjected to solution treatment (temperature 540℃, time 30min) and aging treatment (temperature 180℃, time 8h);
[0234] The shape of the composite board is improved by a tension leveling process;
[0235] A 2mm composite board is used as the first substrate, and a 0.2mm first metal layer (copper layer) is laminated on the first surface of the first substrate to form the first plate.
[0236] The first plate undergoes multiple rolling, annealing, polishing, and trimming processes, reducing its thickness from 2.2 mm to 0.215 mm. The thickness of the first metal layer is 0.015 mm, and the thickness of the first substrate is 0.2 mm.
[0237] The second matrix was prepared using polyimide;
[0238] A second metal layer (copper layer) is laminated on the second surface of the second substrate to form a second plate. The total thickness of the second plate is 0.06 mm, wherein the thickness of the second metal layer is 0.015 mm and the thickness of the second substrate is 0.045 mm.
[0239] The pre-set structural features are formed on the first plate by stamping; the pre-set structural features are formed on the second plate by molding.
[0240] The first plate and the second plate are sealed together by diffusion welding to form a heat dissipation cavity;
[0241] The plate is prepared through processes such as vacuuming and liquid injection.
[0242] The plate and frame are assembled, and the plate and frame are fixedly connected by applying glue and fasteners, and finally the shell assembly is made.
[0243] In this embodiment, the first plate with a thickness of 0.215 mm has an elastic modulus of 120 GPa, a yield strength of 350 MPa, an elongation of 4%, a density of 3.26 g / cm3, and a hardness of 145 HV. After diffusion welding (300℃-2h) process, the hardness of the first plate is 140 HV and the yield strength is 320 MPa. That is, the solid solution strengthening and grain refinement strengthening effects of manganese enhance the composite plate's resistance to annealing softening and reduce the impact of diffusion welding at 300℃ on the yield strength and hardness of the first plate.
[0244] In the third embodiment, when the plate is used as a heat spreader, and both the first and second substrates of the heat spreader are made of the aforementioned composite material, the method for preparing the plate includes:
[0245] A matrix casting rod was prepared by taking aluminum particles, magnesium particles, silicon particles, copper particles and manganese particles. In the matrix casting rod, the weight percentage of magnesium is 0.4%, the weight percentage of silicon is 0.6%, the weight percentage of copper is 1%, the weight percentage of manganese is 0.5%, and the remainder is aluminum.
[0246] The matrix casting rod was made into matrix powder by gas atomization process, and the median particle size of the matrix powder was 15μm;
[0247] Silicon carbide powder and matrix powder were prepared. The median particle size of the silicon carbide powder was 1 μm, the mass of the silicon carbide powder was 30%, and the mass of the matrix powder was 70%. The silicon carbide powder and matrix powder were put into a ball mill and mixed to form a composite powder. The ball mill speed was 40 r / min, the ball milling time was 20 h, and the ball-to-material ratio was 2:1 to achieve uniform dispersion of silicon carbide.
[0248] The mixed powder is made into an ingot by cold pressing, vacuum degassing and hot isostatic pressing.
[0249] The blank is extruded or hot-rolled into a plate with a thickness of 6mm;
[0250] A 6mm thick plate is processed through surface oxide removal and multiple rolling, annealing, polishing and trimming processes to produce a 2mm thick composite plate.
[0251] The composite board was subjected to solution treatment (temperature 540℃, time 30min) and aging treatment (temperature 180℃, time 8h);
[0252] The shape of the composite board is improved by a tension leveling process;
[0253] A 2mm composite board is used as the first substrate, and a 0.2mm first metal layer (copper layer) is laminated on the first surface of the first substrate to form a first plate; a 2mm composite board is used as the second substrate, and a 0.2mm second metal layer (copper layer) is laminated on the second surface of the second substrate to form a second plate;
[0254] The first plate undergoes multiple rolling, annealing, polishing, and trimming processes, reducing its thickness from 2.2 mm to 0.215 mm. The first metal layer has a thickness of 0.015 mm, and the first substrate has a thickness of 0.2 mm. The second plate undergoes the same multiple rolling, annealing, polishing, and trimming processes, reducing its thickness from 2.2 mm to 0.06 mm. The second metal layer has a thickness of 0.015 mm, and the second substrate has a thickness of 0.045 mm.
[0255] Pre-defined structural features are formed on the first and second plates using a stamping process.
[0256] The first plate and the second plate are sealed together by diffusion welding to form a heat dissipation cavity;
[0257] The plate is prepared through processes such as vacuuming and liquid injection.
[0258] The plate and frame are assembled, and the plate and frame are fixedly connected by applying glue and fasteners, and finally the shell assembly is made.
[0259] In this embodiment, the first plate with a thickness of 0.215 mm has an elastic modulus of 130 GPa, a yield strength of 400 MPa, an elongation of 4%, a density of 3.26 g / cm3, and a hardness of 150 HV; the second plate with a thickness of 0.045 mm has an elastic modulus of 130 GPa, a yield strength of 400 MPa, an elongation of 4%, a density of 4.3 g / cm3, and a hardness of 150 HV.
[0260] For the same or similar parts among the various embodiments in this specification, please refer to each other.
Claims
1. A composite material, characterized in that, The composite material includes a matrix and a reinforcing phase, wherein the reinforcing phase is dispersed in the matrix; The matrix includes aluminum, magnesium, silicon, copper, and manganese. The reinforcing phase is silicon carbide, the mass of the reinforcing phase is G1, and the mass of the matrix is G2. G1 and G2 satisfy the following conditions: 20% ≤ G1 / (G1+G2) ≤ 40%, 60% ≤ G2 / (G1+G2) ≤ 80%.
2. The composite material according to claim 1, characterized in that, The median particle size D1 of the silicon carbide satisfies: 0.5μm≤D1≤3μm.
3. The composite material according to claim 1 or 2, characterized in that, The mass of magnesium, g1, satisfies the following condition: 0.5% ≤ g1 / G2 ≤ 1.2%. The mass of silicon element g2 satisfies: 0.5% ≤ g2 / G2 ≤ 1.0%; The mass of copper element g3 satisfies: 0.4% ≤ g3 / G2 ≤ 1.6%; The mass of manganese element g4 satisfies: 0 < g4 / G2 ≤ 0.8%; The mass of aluminum element g5 satisfies: 95.4% ≤ g5 / G2 < 98.6%.
4. The composite material according to any one of claims 1 to 3, characterized in that, The composite material satisfies at least one of the following three conditions: the density of the composite material is less than or equal to 4 g / cm3, the Vickers hardness of the composite material is greater than or equal to 130 HV, and the elastic modulus of the composite material is greater than or equal to 100 GPa.
5. The composite material according to any one of claims 1 to 4, characterized in that, The composite material further includes graphene, which is dispersed within the matrix; The mass of the graphene is G3, and G3 satisfies: G3 / (G1+G2+G3)≤0.5%.
6. The composite material according to claim 5, characterized in that, The graphene is a redox graphene.
7. The composite material according to any one of claims 1 to 6, characterized in that, The yield strength of the composite material is greater than or equal to 300 MPa.
8. A plate, characterized in that, At least a portion of the plate is made of a composite material; The composite material includes a matrix and a reinforcing phase, wherein the reinforcing phase is dispersed in the matrix; The matrix includes aluminum, magnesium, silicon, copper, and manganese. The reinforcing phase is silicon carbide, the mass of the reinforcing phase is G1, and the mass of the matrix is G2. G1 and G2 satisfy the following conditions: 20% ≤ G1 / (G1+G2) ≤ 40%, 60% ≤ G2 / (G1+G2) ≤ 80%.
9. The plate body according to claim 8, characterized in that, The median particle size D1 of the silicon carbide satisfies: 0.5μm≤D1≤3μm.
10. The plate body according to claim 8 or 9, characterized in that, In the matrix, the mass g1 of magnesium satisfies: 0.5% ≤ g1 / G2 ≤ 1.2%; The mass of silicon element g2 satisfies: 0.5% ≤ g2 / G2 ≤ 1.0%; The mass of copper element g3 satisfies: 0.4% ≤ g3 / G2 ≤ 1.6%; The mass of manganese element g4 satisfies: 0 < g4 / G2 ≤ 0.8%; The mass of aluminum element g5 satisfies: 95.4% ≤ g5 / G2 < 98.6%.
11. The plate body according to any one of claims 8 to 10, characterized in that, The composite material satisfies at least one of the following three conditions: the density of the composite material is less than or equal to 4 g / cm3, the Vickers hardness of the composite material is greater than or equal to 130 HV, and the elastic modulus of the composite material is greater than or equal to 100 GPa.
12. The plate body according to any one of claims 8 to 11, characterized in that, The composite material further includes graphene, which is dispersed within the matrix; The mass of the graphene is G3, and G3 satisfies: G3 / (G1+G2+G3)≤0.5%.
13. The plate body according to claim 12, characterized in that, The graphene is a redox graphene.
14. The plate body according to any one of claims 8 to 13, characterized in that, The yield strength of the composite material is greater than or equal to 300 MPa.
15. The plate body according to any one of claims 8 to 14, characterized in that, The plate is a medium plate, and the thickness of the plate is 0.1mm-3mm.
16. The plate body according to any one of claims 8 to 14, characterized in that, The plate is a heat dissipation plate, and the plate includes a first substrate, a second substrate and a capillary structure. The first substrate and the second substrate form a heat dissipation cavity, and the capillary structure is located in the heat dissipation cavity and is connected to the first substrate. The first substrate is made of the composite material and has a thickness of 0.1 mm to 0.3 mm.
17. The plate body according to claim 16, characterized in that, The material of the second substrate is polyimide; Alternatively, the second substrate may be made of the composite material, and the thickness of the second substrate may be 0.03 mm to 0.15 mm.
18. The plate body according to claim 16 or 17, characterized in that, The first substrate has a first surface, and the second substrate has a second surface. Along the thickness direction of the plate, the first surface is located on the side of the first substrate closer to the second substrate, and the second surface is located on the surface of the second substrate closer to the first substrate. The plate also includes a first metal layer and a second metal layer. The first metal layer is disposed on the first surface, and the second metal layer is disposed on the second surface. The first metal layer and the second metal layer are welded and fixed together, or the first metal layer and the second metal layer are bonded and fixed together.
19. The plate body according to claim 18, characterized in that, The thickness of the first metal layer is 7μm-20μm, and the thickness of the second metal layer is 7μm-20μm.
20. The plate body according to any one of claims 16 to 19, characterized in that, The first substrate has a third surface, and the second substrate has a fourth surface. Along the thickness direction of the plate, the third surface is located on the side of the first substrate away from the second substrate, and the fourth surface is located on the side of the second substrate away from the first substrate. The plate also includes a third metal layer and a fourth metal layer, the third metal layer being disposed on the third surface and the fourth metal layer being disposed on the fourth surface.
21. A housing assembly, characterized in that, The housing assembly includes: frame; The plate body according to any one of claims 8 to 20, wherein the plate body is fixedly connected to the frame or integrally formed.
22. An electronic device, characterized in that, The electronic device includes the plate body according to any one of claims 8 to 20.
23. An electronic device, characterized in that, The electronic device includes: The housing assembly as claimed in claim 21; A display screen is mounted on the housing assembly.
24. A method for preparing a composite material, characterized in that, The method for preparing the composite material includes: Take aluminum particles, magnesium particles, silicon particles, copper particles, and manganese particles, and prepare a matrix according to a first preset ratio; The matrix is ground into matrix powder; Take silicon carbide powder, and mix the matrix powder and the silicon carbide powder in a second preset ratio to form a composite powder; The composite powder is then processed into a composite plate with a second predetermined thickness. In the composite board, the mass of silicon carbide is G1, and the sum of the masses of aluminum, magnesium, silicon, copper and manganese is G2. G1 and G2 satisfy the following conditions: 20% ≤ G1 / (G1+G2) ≤ 40%, 60% ≤ G2 / (G1+G2) ≤ 80%.
25. The method for preparing the composite material according to claim 24, characterized in that, The first preset ratio satisfies: The mass of magnesium, g1, satisfies the following condition: 0.5% ≤ g1 / G2 ≤ 1.2%. The mass of silicon element g2 satisfies: 0.5% ≤ g2 / G2 ≤ 1.0%; The mass of copper element g3 satisfies: 0.4% ≤ g3 / G2 ≤ 1.6%; The mass of manganese element g4 satisfies: 0 < g4 / G2 ≤ 0.8%; The mass of aluminum element g5 satisfies: 95.4% ≤ g5 / G2 < 98.6%.
26. The method for preparing the composite material according to any one of claims 24 or 25, characterized in that, The median particle size of the silicon carbide is 0.5 μm-3 μm; The median particle size of the matrix powder is 2μm-20μm.
27. The method for preparing the composite material according to any one of claims 24 to 26, characterized in that, The step of mixing the matrix powder and the silicon carbide powder in a second preset ratio to form a composite powder includes: Take graphene powder, and mix the graphene powder, the matrix powder and the silicon carbide powder in a ball mill according to a third preset ratio to form a composite powder. The rotation speed of the ball mill is 30 r / min-60 r / min, the ball milling time is 18h-25h, and the ball-to-material ratio is 1:1 to 3:
1. The third preset ratio satisfies: The mass of the silicon carbide is G1, the mass of the matrix is G2, the mass of the graphene powder is G3, and G3 / (G1+G2+G3)≤0.5%.
28. The method for preparing the composite material according to any one of claims 24 to 27, characterized in that, The step of forming the composite powder into a composite plate with a second predetermined thickness includes: The composite powder is made into a thick plate with a first preset thickness of 3mm-10mm; The thick plate is made into a composite plate with a second preset thickness of 0.1mm-3mm; The composite board is then straightened and leveled.
29. The method for preparing the composite material according to any one of claims 24 to 28, characterized in that, After the step of forming the composite powder into a composite plate with a second predetermined thickness, the method for preparing the composite material includes: The composite board is subjected to solution treatment and aging treatment. The solution treatment temperature is 400℃-600℃ and the solution treatment time is 20min-40min. The aging treatment temperature is 150℃-250℃ and the aging treatment time is 7h-12h.