Evolution of microstructure and its effect on wear and mechanical properties of spray cast Al-12Si alloy

► Microstructure of spray cast and HIPed Al-12Si alloy consisted of finely divided and globular shaped Si in the Al matrix. ► Microstructure of chill cast Al-12Si alloy was coarse and consisted of an eutectic mixture of α-Al + Si needles. ► The wear rate of spray cast and HIPed alloy was invariably lower than that of chill cast alloy over a wide range of sliding velocity. ► Spray cast alloy followed by HIPing showed considerable improvement in its strength, ductility and hardness over that of chill cast alloy. ► Finer microstructure in the spray cast and HIPed alloy resulted in better mechanical and wear properties.