SiC增强Al基复合材料的制备和性能

Fabrication and Properties of SiC Reinforced Al Composite

摘要:

采用模压成型和真空压力浸渗工艺制备了高体积分数SiC增强Al基复合材料(AlSiC)。物相和显微结构研究结果表明, 此种方法制备的AlSiC复合材料, 组织致密且大小两种粒径的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脆性相。对Al₄C₃相形成机理进行了分析, 指出6061铝合金中的Si元素和真空压力浸渗工艺条件有利于防止脆性相Al4C3的形成。热性能测试结果表明, 随温度升高, 复合材料热膨胀系数先增大后减小, 315℃附近出现最大值。所获得复合材料的平均热膨胀系数为7.00×10^-6℃^-1, 热导率为155.1W/mK, 密度为3.1g/cm³, 完全满足高性能电子封装材料的要求。

Abstract:

The SiC reinforced Al composite (AlSiC) with high SiC volume fraction was prepared by combination of compression molding and vacuum pressure infiltration. Detailed analysis on microstructure and phase was carried out. The results show that the AlSiC composite fabricated by the above-mentioned methods is free of porosity, and the SiC particles are distributed uniformly and high interfacial bonding strength is achieved. Moreover, the interfacial reaction is well controlled so that some harm phases, especially Al₄C₃ fragility, are absent from interfacial reaction products. The mechanism behind the experimental phenomenon was analyzed in detail. It is indicated that the silicon addition in the 6061 aluminum alloy and process conditions of vacuum pressure infiltration can effectively prevent the formation of Al₄C₃ fragility phase. Thermal properties of the samples were also tested. The results indicate that the thermal expansion coefficient of aluminum silicon carbide increase first and then decrease with the increase of temperature, reaching the maximum at 315℃. The coefficient of thermal expansion of aluminum silicon carbide is 7.00×10^-6℃^-1, the thermal conductivity is 155.1W/m·K, and the density is 3.1g/cm³. The aluminum silicon carbide composite can fully meet high-end electronic packaging materials requirements.