高性能SiC增强Al基复合材料的显微组织和热性能

Microstructure and thermal properties of high-performance SiC reinforced Al matrix composite

采用模压成型和无压浸渗工艺制备了高体积分数SiC增强Al基复合材料(AlSiC),对其物相和显微结构进行研究。结果表明:用上述方法制备的AlSiC复合材料组织致密,两种粒径的SiC颗粒均匀分布于Al基质中,界面结合强度高;SiC增强颗粒与Al基质界面反应控制良好,未出现Al4C3等脆性相。分析指出:Al合金中Si元素的存在有利于防止脆性相Al4C3的形成,Mg元素的加入提高了Al基体和SiC增强体之间的润湿性。所获得复合材料的平均热膨胀系数为9.31×10 6K 1,热导率为238 W/(m.K),密度为2.97 g/cm3,表现出了良好的性能,完全满足高性能电子封装材料的要求。

The SiC reinforced Al matrix composite （AlSiC） with high SiC volume fraction was prepared by combination of compression molding for SiC preform and pressureless infiltration. The microstructure and phase of AlSiC composite were studied. The results show that the AlSiC composite fabricated by above-mentioned methods is free of porosity, the SiC particles with two sizes are distributed uniformly, and the high interfacial bonding strength is achieved. Moreover, the interfacial reaction is well controlled so that some harm phases especially Al4C3 fragility phase are absence from interfacial reaction products. The physical mechanism behind those experimental phenomena was analyzed in detail. The existence of silicon in the aluminum alloy prevents the formation of Al4C3 fragility phase and the addition of magnesium to the aluminum alloy significantly improves the wetting property of SiC with aluminum. The thermal expansion coefficient of AlSiC composite is 9.31 X 10-6 K-l, the thermal conductivity is 238 W/（m.K）, and the density is 2,97 g/cm3. The AlSiC composite exhibits excellent properties and can fully meets the requirements of high-end electronic packaging materials.