Preparation, Microstructure, and Thermal Properties of Aluminum/Carbon Composites

Aluminum (Al)/carbon composites are considered to be promising thermal management materials in the application field of electronic packaging. In this work, highly densed Al/graphite, Al/carbon fibers (CFs), and Al/graphite/CFs composites were successfully prepared by a hot extrusion process. Besides, small amounts of Al-Si alloy addition and Ni-coating were applied to improve the interfacial bonding between Al matrix and carbon in the composites. The microstructure, thermal conductivity (TC), and coefficient of thermal expansion (CTE) of the hot-extruded Al/carbon composites were investigated. The results showed that hot extrusion can lead to deformation of graphite and align the graphite and CFs along the extrusion direction. Al-Si alloy addition and Ni-coating can effectively improve the Al/carbon interfacial bonding, thus decreasing the interfacial thermal resistance. The Al/graphite composites showed relatively high TC and CTE values, while the Al/CFs composites exhibited relatively low TC and CTE values. In contrast, the Al/graphite/CFs hybrid composites presented an excellent balance between TC and CTE.