Tailoring microstructure and its effect on wear behavior of an Al–7Si alloy reinforced with in situ formed Al3Ti particulates

Abstract

The microstructure and wear behavior of an Al–7Si alloy reinforced with in situ Al3Ti particulates were studied. The effects of Sr modification and heat treatment were also investigated. Sr and Al3Ti particulates had clear effects on modifying the morphology of eutectic Si and the microstructure of the Al–Si alloy, playing a key role in improving the hardness and wear properties of the Al3Ti/Al–7Si–Sr composite. T6 heat treatment was performed to spheroidized coarse eutectic Si, reducing stress concentration and further improving the hardness and wear properties of the composites. Among them, the Al3Ti/Al–7Si–Sr composite displayed the highest hardness and the lowest friction coefficient in both as-cast and T6 heat treated states attributed to the combined effects of Sr modification and Al3Ti reinforcement.