High-thermal-conductivity low-thermal-expansion-coefficient chopped carbon fiber reinforced aluminum-based composite material and preparation method thereof
By using a pressure infiltration process to infuse short-cut carbon fibers with aluminum matrix composites, a carbon fiber reinforced aluminum matrix composite material with high thermal conductivity and low coefficient of thermal expansion was prepared. This solved the problem of insufficient performance of traditional materials and realized an electronic packaging material with high thermal conductivity, low thermal expansion and excellent mechanical properties, which is suitable for high-end electronic devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-03
AI Technical Summary
Traditional electronic packaging materials cannot simultaneously meet the requirements of low coefficient of thermal expansion, high thermal conductivity, and good mechanical properties, leading to problems such as thermal stress, poor heat dissipation, and structural deformation in high-end electronic devices.
Short-cut carbon fibers with high thermal conductivity and low coefficient of thermal expansion are combined with an aluminum matrix to prepare carbon fiber reinforced aluminum matrix composites through a pressure infiltration process. By combining the high axial thermal conductivity and negative thermal expansion characteristics of carbon fibers, the overall thermal conductivity of the material is improved and the coefficient of thermal expansion is reduced.
It achieves high thermal conductivity, low thermal expansion, excellent mechanical properties and good processing performance in electronic packaging materials, adapting to the complex working conditions and extreme environments of high-end electronic devices and extending device life.
Smart Images
Figure CN121781024A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a short-cut carbon fiber reinforced aluminum matrix composite material with high thermal conductivity and low coefficient of thermal expansion, and its preparation method. Background Technology
[0002] In modern industrial fields such as aerospace, transportation, and high-end electronics, electronic communication technology is rapidly iterating towards higher frequencies, greater integration, and miniaturization. This presents increasingly stringent performance challenges for the accompanying electronic packaging technology. As a core guarantee for the stable operation of electronic devices, electronic packaging's core functions include achieving electrical connection between the chip and external circuits, providing mechanical support, and ensuring efficient heat dissipation. The performance of the packaging material directly determines the operational stability, reliability, and lifespan of the electronic device. Especially in extreme environments such as aerospace, high-frequency vibration conditions in transportation, and long-term full-load operation of high-end electronics, electronic devices often need to operate continuously under complex conditions of long-term thermal cycling and multi-field coupling. This places comprehensive performance requirements on packaging materials, demanding lightweight, high modulus, low expansion, high thermal conductivity, and strong environmental adaptability.
[0003] Specifically, electronic packaging materials suitable for high-end applications must meet the following key performance indicators: First, the packaging structure of electronic devices is usually composed of multiple materials. If the difference in thermal expansion coefficients between different materials is too large, significant thermal stress will be generated during long-term temperature cycling. This thermal stress will gradually accumulate and cause damage such as microcracks and interface delamination in the packaging structure, ultimately leading to the failure of electronic devices. Therefore, the packaging material must have a low thermal expansion coefficient that matches the chip and substrate to ensure dimensional stability over a wide temperature range. Second, with the increase in the integration of electronic devices, the power density per unit volume increases significantly, generating a large amount of heat during operation. If the heat cannot be dissipated in time, the internal temperature of the device will rise sharply, which will not only reduce the working efficiency of the electronic device but also accelerate material aging and shorten the device life. Therefore, high thermal conductivity is the core prerequisite for ensuring efficient heat dissipation and stable operation of electronic devices. Third, packaging materials... First, it needs to provide reliable mechanical support for electronic devices to resist deformation caused by external vibration, impact, and internal stress. High elastic modulus can ensure that the components have sufficient rigidity to avoid affecting the electrical connection accuracy and mechanical stability of electronic devices due to structural deformation. Second, whether it is the strict control of the payload weight in the aerospace field or the demand for lightweighting in transportation and portable electronic devices, the packaging materials must have low density characteristics to achieve a lightweight design of the overall structure. Third, modern electronic packaging components are often characterized by complex shapes and high dimensional accuracy requirements. The materials must be easy to process and form through casting, forging, machining, etc., to meet the diverse packaging structure design requirements. Fourth, in the high-altitude radiation and high temperature difference environment of aerospace, the high humidity and salt spray environment of marine transportation, and the corrosive environment of industrial scenarios, the packaging materials must be able to resist the erosion of extreme conditions, ensure the long-term stability of their performance, and provide continuous and reliable protection for electronic devices.
[0004] However, current traditional electronic packaging materials generally suffer from performance shortcomings, making it difficult to simultaneously meet the stringent comprehensive performance requirements of the aforementioned high-end fields. This has created a technical bottleneck where "low coefficient of thermal expansion, high thermal conductivity, and good mechanical properties are difficult to achieve simultaneously." Specifically, while metals and their alloys possess low coefficients of thermal expansion and good formability, their high density makes it difficult to meet the demands for lightweight materials. Furthermore, the thermal conductivity and elastic modulus of some metals are not suitable for the requirements of high-end devices. Ceramic materials have the advantages of low density and low coefficient of thermal expansion, but their brittleness and extremely high difficulty in forming and processing make it impossible to fabricate complex-shaped packaging components. Their poor impact resistance also limits their application under dynamic operating conditions. Carbon materials (such as graphite and carbon fiber bulk materials) exhibit excellent characteristics of low density, low coefficient of thermal expansion, and high thermal conductivity, but they also suffer from difficulties in forming and processing, poor interfacial bonding with metal substrates, and limited mechanical load-bearing capacity, making them unsuitable for direct use as packaging structure materials.
[0005] To overcome the performance limitations of traditional materials, the development of novel electronic packaging materials possessing low coefficients of thermal expansion, high thermal conductivity, high elastic modulus, low density, and excellent moldability has become a key breakthrough for driving technological upgrades in strategic fields such as aerospace and high-end electronics. Against this backdrop, metal matrix composites have attracted widespread attention from academia and industry due to their strong designability and ability to integrate the advantages of both metals and reinforcing phases. By combining high-performance reinforcing phases (such as ceramic particles and carbon fibers) with a metal matrix (such as aluminum, magnesium, and copper), metal matrix composites can achieve synergistic complementarity between the properties of the reinforcing phase and the matrix material, thereby controlling key indicators such as the coefficient of thermal expansion, thermal conductivity, and mechanical properties of the composite material. Summary of the Invention
[0006] The present invention aims to solve the problem that it is difficult to achieve low thermal expansion coefficient, high thermal conductivity and good mechanical properties in traditional electronic packaging materials at the same time, and provides a short-cut carbon fiber reinforced aluminum matrix composite material with high thermal conductivity and low thermal expansion coefficient and its preparation method.
[0007] The present invention discloses a short-cut carbon fiber reinforced aluminum matrix composite material with high thermal conductivity and low coefficient of thermal expansion, which is composed of carbon fiber and aluminum-containing material, wherein the aluminum-containing material is pure aluminum or aluminum alloy; the carbon fiber accounts for 40% to 60% of the total volume of the composite material.
[0008] The preparation method of the high thermal conductivity and low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material of the present invention is carried out according to the following steps:
[0009] 1. The carbon fiber is dried in an oven at low temperature for later use to obtain pre-made fiber;
[0010] 2. The pre-fabricated fibers are laid in the mold to form a fiber pre-fabricated block at the bottom of the mold; and then compacted by a vibrating table to obtain the blank to be cold-pressed.
[0011] 3. The blank to be cold-pressed is cold-pressed into a blank under a pressure of 5~50MPa, and then placed in an electric furnace along with the mold, and kept at a temperature of 550~650℃ for 2~6 hours to obtain the material preform.
[0012] IV. Melt the aluminum-containing material at a temperature of 700~900℃ for 2~6 hours to obtain an aluminum-containing melt; the aluminum-containing material is aluminum or an aluminum alloy.
[0013] 5. The aluminum-containing molten liquid is poured into the gap of the material preform by pressure infiltration and pressurized infiltration. The pressure is maintained at 5~250MPa for 5~30min. After cooling at room temperature, the material is demolded to obtain a high thermal conductivity and low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material. The volume fraction of carbon fiber in the high thermal conductivity and low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material is 40~60%.
[0014] The beneficial effects of this invention are:
[0015] This invention introduces carbon fibers with high axial thermal conductivity and negative thermal expansion, and uses a pressure infiltration process to prepare composite materials, thereby obtaining fiber-reinforced aluminum-based electronic packaging materials with a high carbon fiber content (40~60 vol.%). The fiber-reinforced aluminum-based electronic packaging material prepared by this invention combines the excellent processability, certain strength, and plasticity of the aluminum matrix with the high elastic modulus, high axial thermal conductivity, and negative thermal expansion characteristics of carbon fibers. The carbon fibers are randomly distributed within the axial cross-section of the bulk material, allowing them to isotropically exert their high thermal conductivity and negative thermal expansion advantages in a plane. Due to the high graphitization of the carbon fibers, the ordered arrangement of graphite layers parallel to the fiber axis weakens the scattering of phonons during transmission, thus exhibiting excellent axial thermal conductivity. The carbon fibers improve the overall thermal conductivity of the composite material through phonon thermal conduction. The randomly distributed short-cut carbon fibers in a plane effectively avoid the problem of overly tortuous heat conduction paths caused by the random orientation and agglomeration of long fibers. This reduces the degradation loss of thermal conductivity; carbon fiber itself has a high elastic modulus, which can improve the overall elastic modulus of the composite material through the mixing law; carbon fiber has the intrinsic characteristics of axial negative thermal expansion and radial low expansion. On the one hand, carbon fiber can directly constrain the thermal expansion of the aluminum matrix through good interfacial bonding, inhibiting the free expansion of the matrix when the temperature rises. On the other hand, the axial negative thermal expansion effect of carbon fiber will form a contraction trend opposite to the thermal expansion direction of the aluminum matrix, providing a buffer space for the thermal expansion of the matrix, effectively offsetting part of the expansion effect of the matrix, and reducing the overall thermal expansion coefficient of the composite material; the high graphitization degree of carbon fiber and the short contact time between Al liquid and carbon fiber in the pressure impregnation process can significantly inhibit the formation of brittle phase Al4C3, forming a good interfacial bond. On the one hand, it can improve the mechanical properties and thermal stability of the composite material through stress transfer, and on the other hand, it can reduce the interfacial thermal resistance and improve the thermal conductivity of the composite material. Attached Figure Description
[0016] Figure 1 A schematic diagram of a short-cut carbon fiber reinforced aluminum matrix composite material with high thermal conductivity and low coefficient of thermal expansion.
[0017] Figure 2 A top view of a short-cut carbon fiber reinforced aluminum matrix composite material with high thermal conductivity and low coefficient of thermal expansion. Detailed Implementation
[0018] Specific Implementation Method 1: This implementation method provides a high thermal conductivity, low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material, which is composed of carbon fiber and aluminum-containing material, wherein the aluminum-containing material is pure aluminum or aluminum alloy; the carbon fiber accounts for 40% to 60% of the total volume of the composite material.
[0019] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the carbon fiber is short-cut carbon fiber with a diameter of 5~20μm, a length of 30~750μm, and an aspect ratio of 1.5~250. Everything else is the same as in Specific Implementation Method One.
[0020] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 in that the carbon fiber is short-cut carbon fiber with a diameter of 5~20μm, a length of 30~200μm, and an aspect ratio of 1.5~150. Everything else is the same as in Specific Implementation Method 1.
[0021] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method One in that the carbon fiber is a mesophase pitch-based carbon fiber, and the axial thermal conductivity of the carbon fiber is 500~1000W / m·K, with an axial coefficient of thermal expansion ≤0. Everything else is the same as in Specific Implementation Method One.
[0022] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method One in that the density of the carbon fiber is ≥1.8 g / cm³. 3 The elastic modulus is ≥600 GPa. Everything else is the same as in Specific Implementation Method 1.
[0023] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method One in that the aluminum-containing material is pure aluminum, 1xxx series aluminum alloy, 2xxx series aluminum alloy, 3xxx series aluminum alloy, 4xxx series aluminum alloy, 5xxx series aluminum alloy, 6xxx series aluminum alloy, 7xxx series aluminum alloy, or Al-Si series aluminum alloy. Everything else is the same as in Specific Implementation Method One.
[0024] Specific Implementation Method Seven: The preparation method of a high thermal conductivity, low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material in this implementation method is carried out according to the following steps:
[0025] 1. The carbon fiber is dried in an oven at low temperature for later use to obtain pre-made fiber;
[0026] 2. The pre-fabricated fibers are laid in the mold to form a fiber pre-fabricated block at the bottom of the mold; and then compacted by a vibrating table to obtain the blank to be cold-pressed.
[0027] 3. The blank to be cold-pressed is cold-pressed into a blank under a pressure of 5~50MPa, and then placed in an electric furnace along with the mold, and kept at a temperature of 550~650℃ for 2~6 hours to obtain the material preform.
[0028] IV. Melt the aluminum-containing material at a temperature of 700~900℃ for 2~6 hours to obtain an aluminum-containing melt; the aluminum-containing material is aluminum or an aluminum alloy.
[0029] 5. The aluminum-containing molten liquid is poured into the gap of the material preform by pressure infiltration and pressurized infiltration. The pressure is maintained at 5~250MPa for 5~30min. After cooling at room temperature, the material is demolded to obtain a high thermal conductivity and low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material. The volume fraction of carbon fiber in the high thermal conductivity and low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material is 40~60%.
[0030] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Seven in that the mold described in step two is a steel mold or a graphite mold, the bottom of the mold has vent holes, and the mold is a disposable or reusable mold. Everything else is the same as in Specific Implementation Method Seven.
[0031] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Seven in that the thickness of the prefabricated fiber layer in step two is ≥0.5mm. Everything else is the same as in Specific Implementation Method Seven.
[0032] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Seven in that, in step three, the blank to be cold-pressed is cold-pressed into a blank under a pressure of 5~30MPa. Everything else is the same as in Specific Implementation Method Seven.
[0033] Specific Implementation Method Eleven: This implementation method differs from Specific Implementation Method Seven in that demolding does not require cooling to room temperature in step five. Everything else is the same as in Specific Implementation Method Seven.
[0034] The beneficial effects of the present invention are verified using the following embodiments:
[0035] Example 1: A method for preparing a short-cut carbon fiber reinforced aluminum matrix composite material with high thermal conductivity and low coefficient of thermal expansion is carried out according to the following steps:
[0036] 1. Dry the carbon fiber in a low-temperature oven at 60℃ for 120 minutes until it is ready for use. The fiber diameter is 15μm and the length is 200μm. The carbon fiber is mesophase pitch-based carbon fiber with an axial thermal conductivity of 500~1000W / m·K and an axial thermal expansion coefficient ≤0.
[0037] 2. The pre-fabricated fibers are laid in the mold to form a fiber pre-fabricated block at the bottom of the mold; the fiber thickness is 10mm; and it is compacted by a vibrating table to obtain the blank to be cold-pressed. The inner diameter of the steel mold is 94mm.
[0038] 3. The blank to be cold-pressed is cold-pressed into a blank under a pressure of 5~50MPa, and then placed in an electric furnace along with the mold, and kept at a temperature of 550~650℃ for 2~6 hours to obtain the material preform.
[0039] IV. Melt the aluminum-containing material at a temperature of 700~900℃ for 2~6 hours to obtain an aluminum-containing melt; the aluminum-containing material is aluminum or an aluminum alloy.
[0040] 5. The aluminum-containing molten liquid is poured and impregnated into the gaps of the material preform under pressure impregnation. The pressure is maintained at 30~250MPa for 5~30min. After cooling at room temperature, the material is demolded to obtain a high thermal conductivity and low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material. The volume fraction of carbon fiber in the high thermal conductivity and low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material is 50%.
[0041] The high thermal conductivity, low coefficient of thermal expansion short-cut carbon fiber reinforced aluminum matrix composite material (50% MPCF / 6061Al composite material) obtained from Example 1 has an overall density of 2.5 g / cm³. 3 The diameter is 87 mm and the height is 50 mm. The radial thermal conductivity is 200 W / m·K, the radial thermal expansion coefficient at room temperature to 100℃ is ≤9 ppm / K, the radial flexural strength is ≥80 MPa, and the elastic modulus is ≥110 GPa. Table 1 shows the thermo-mechanical test results of the high thermal conductivity and low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material obtained in Example 1.
[0042] Table 1
[0043]
Claims
1. A short-cut carbon fiber reinforced aluminum matrix composite material with high thermal conductivity and low coefficient of thermal expansion, characterized in that... The high thermal conductivity and low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material is composed of carbon fiber and aluminum-containing material, wherein the aluminum-containing material is pure aluminum or aluminum alloy; the carbon fiber accounts for 40% to 60% of the total volume of the composite material.
2. The high thermal conductivity, low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material according to claim 1, characterized in that... The carbon fiber is a short-cut carbon fiber with a diameter of 5~20μm, a length of 30~750μm, and an aspect ratio of 1.5~250.
3. The high thermal conductivity, low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material according to claim 1, characterized in that... The carbon fiber is a mesophase pitch-based carbon fiber, and the axial thermal conductivity of the carbon fiber is 500~1000W / m·K, and the axial thermal expansion coefficient is ≤0.
4. The high thermal conductivity, low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material according to claim 1, characterized in that... The carbon fiber density is ≥ 1.8 g / cm³. 3 Elastic modulus ≥600GPa.
5. The high thermal conductivity, low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material according to claim 1, characterized in that... The aluminum-containing material is pure aluminum, 1xxx series aluminum alloy, 2xxx series aluminum alloy, 3xxx series aluminum alloy, 4xxx series aluminum alloy, 5xxx series aluminum alloy, 6xxx series aluminum alloy, 7xxx series aluminum alloy or Al-Si series aluminum alloy.
6. The method for preparing a high thermal conductivity, low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material as described in claim 1, characterized in that... The preparation method of high thermal conductivity and low coefficient of thermal expansion short-cut carbon fiber reinforced aluminum matrix composite material is carried out according to the following steps:
1. The carbon fiber is dried in an oven at low temperature for later use to obtain pre-made fiber; 2. The pre-fabricated fibers are laid in the mold to form a fiber pre-fabricated block at the bottom of the mold; The blank is then compacted using a vibrating table to obtain the material to be cold-pressed.
3. The blank to be cold-pressed is cold-pressed into a blank under a pressure of 5~50MPa, and then placed in an electric furnace along with the mold, and kept at a temperature of 550~650℃ for 2~6 hours to obtain the material preform. IV. Melt the aluminum-containing material at a temperature of 700~900℃ for 2~6 hours to obtain an aluminum-containing melt; the aluminum-containing material is aluminum or an aluminum alloy.
5. The aluminum-containing molten liquid is poured into the gap of the material preform by pressure infiltration and pressurized infiltration. The pressure is maintained at 5~250MPa for 5~30min. After cooling at room temperature, the material is demolded to obtain a high thermal conductivity and low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material. The volume fraction of carbon fiber in the high thermal conductivity and low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material is 40~60%.
7. The method for preparing a high thermal conductivity, low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material according to claim 6, characterized in that... The mold mentioned in step two is a steel mold or a graphite mold, with vent holes at the bottom. The mold is either disposable or reusable.
8. The method for preparing a high thermal conductivity, low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material according to claim 6, characterized in that... In step two, the thickness of the prefabricated fiber layer should be ≥0.5mm.
9. The method for preparing a high thermal conductivity, low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material according to claim 6, characterized in that... In step three, the blank to be cold-pressed is cold-pressed into a blank under a pressure of 5~30MPa.
10. The method for preparing a high thermal conductivity, low thermal expansion coefficient short-cut carbon fiber reinforced aluminum matrix composite material according to claim 6, characterized in that... In step five, demolding is performed without cooling to room temperature.