Enhanced thermal conductivity in diamond/aluminum composites: Comparison between the methods of adding Ti into Al matrix and coating Ti onto diamond surface

The enhancement of thermal conductivity (TC) in diamond/A356 aluminum alloy composites was investigated by comparing the Ti coating on diamond surface with the Ti content in Al matrix. Diamond/A356 aluminum alloy composites with Ti coating on diamond surface (Ti–diamond/aluminum) and Ti added into matrix (diamond/aluminum-Ti) were fabricated by gas pressure infiltration. The microstructure, TC and interfacial thermal conductance (ITC) of these two types of composites were compared. Unlike the homogeneous interfacial bonding for the Ti–diamond/aluminum composite, it exhibits a transition from weak to strong interface bonding as the content of Ti in the Al alloy increases. The method of coating appears more effective than the method of adding active metal into the matrix on enhancing the diamond/aluminum interface thermal conductance with the help of calculation by differential effective medium (DEM) and acoustic mismatch model (AMM).