The effects of Si on the interfacial characteristics of Al-6.25 Si alloy/SiC and Al-11.12 Si alloy / SiC were investigated. The different compositions of aluminium and silicon carbide samples were prepared at various processing temperatures with constant holding time. The characteristics of interface between Al alloy and SiC were evaluated using tensile test and microhardness test. The interface morphologies were evaluated using scanning electron microscope and energy dispersive spectroscopy. The results shown that the interface fracture strength and microhardness values increased at the interface when Si concentration levels were increased.