Effects of pouring temperature and electromagnetic stirring on semi-solid microstructure of hypoeutectic Mg2Si/Al composite

Abstract

In this paper, hypoeutectic Al-Si matrix composite reinforced by 5wt. % Mg2 Si were prepared under different pouring temperature (superheat) and electromagnetic stirring (EMS), and the effects of pouring temperature and EMS on the morphology a nd size distribution of primary α-Al, (α-Al+Mg2Si) eutectic cell and eutectic Mg2Si are investigated. The experimental results show that the low superheat + EMS process not only refines the grain structure of the primary α-Al and (α-Al+Mg2Si) eutectic cell, an d promotes the formation of more non-dendritic structure of the phases, but also refine s the eutectic Mg2Si and changes the nucleation mode of (α-Al+Mg2Si) binary eutectic from the nucleation on primary α-Al under conventional casting to the one on nuclean t particles in the interdendritic liquid under low superheat + EMS.