Microstructure and thermophysical properties of SiC/Al composites mixed with diamond

The thermophysical properties of the SiC/Al composites mixed with diamond (SiC-Dia/Al) were studied through theoretical calculation and experiments. The thermal conductivity and the thermal expansion coefficient of the SiC-Dia/Al were calculated by differential effective medium (DEM) theoretical model and extended Turner model, respectively. The microstructure of the SiC-Dia/Al shows that the combination between SiC particles and Al is close, while that between diamond particles and Al is not close. The experimental results of the thermophysical properties of the SiC-Dia/Al are consistent with the calculated ones. The calculation results show that when the volume ratio of the diamond particles to the SiC particles is 3:7, the thermal conductivity and the thermal expansion coefficient can be improved by 39% and 30% compared to SiC/Al composites, respectively. In other words, by adding a small amount of diamond particles, the thermophysical properties of the composites can be improved effectively, while the cost increases little.