Effect of addition of Si on thermal and electrical properties of Al-Si-Al2O3 composites

Abstract

Al-5wt.%Si-Al2O3, Al-10wt.%Si-Al2O3, Al-20wt.%Si-Al2O3 composites were fabricated by powder metallurgy and in-situ reactive synthesis technology. The impact of the addition of Si on the thermal and electrical properties was tested and analysed for vary in silicon content in Al-Si-Al2O3 composites. Results show that both thermal expansion coefficient and thermal conductivity decreased as silicon content increased because Si and Al2O3 dispersed in the Al matrix uniformly to suppress the high thermal expansion of Al to a large extent as well as the interfacial thermal resistance which led to the decline in thermal conductivity. Electrical resistivity increased when silicon content was increased because low thermal expansion coefficient particles of Si and Al2O3 severely damaged the continuity of the Al matrix which hindered movement of electron in the matrix.