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

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. (paper)