Thermal Properties of Al/AlN Composites Fabricated in Continuous Solid-Liquid Co-Existent State by SPS

Abstract

SiC-particle-dispersed-aluminum (Al) matrix composites were fabricated in solid-liquid co-existent state by Spark Plasma Sintering (SPS) process from the mixture of SiC powders, Al powders and Al-5mass%Si powders. The microstructures and thermal conductivities of the composites fabricated were examined. These composites were all well consolidated by heating at a temperature range between 798 K and 876 K for 1.56 ks during SPS process. No reaction at the interface between the SiC particle and the Al matrix was observed by scanning electron microscopy for the composites fabricated under the sintering conditions employed in the present study. The relative packing density of the Al/SiC composite fabricated was higher than 99 % in a volume fraction range of SiC between 40 % and 55 %. Thermal conductivity of the Al/SiC composite increased with increasing the SiC content in the composite in a volume fraction range between 40 and 50 vol.%. The highest thermal conductivity was obtained for Al-50vol.%SiC composite and reached 252 W/mK. The coefficient of thermal expansion of the composites falls in the upper line of Kerner's model, indicating strong bonding between the SiC particle and the Al matrix in the composite.