Effects of particle size on the thermal physical properties of SiCp/Al composites

The coefficients of thermal expansion (CTEs) of the 20 vol% SiCp/Al composites fabricated by powder metallurgy process were measured and examined from room temperature to 450 degrees C The SiC particles are in three nominal sizes 5 mu m, 20 mu m and 56 mu m. The CTEs of the SiCp/Al composites were shown to be apparently dependent on the particle size. That the larger particle size, the higher CTEs of the composites, is thought to be due to the difference in original thermal residual stresses and matrix plasticity during thermal loading. The thermal conductivity of the composites also increases with particle size increasing.