Effect of Yttrium on the Solidification Process and Performance of Al7SiMg Alloy

Solidification processes of Al7SiMg-xY(0.1wt%,0.3wt%,0.5wt%) alloys were investigated by thermal analysis.The microstructures were observed by using optical microscopy and scanning electron microscopy.Effects of different concentrations of yttrium on tensile performance both as cast and T6 heat treated were studied at room temperature,respectively.The results show that little changes happen in liquidus with increases concentration of yttrium.While it results in obvious depression of solidus and eutectic arrest temperature in solidification process.Moreover,the solidification range increases significantly.The performance is better when concentration of yttrium is 0.1wt%.With increment of yttrium,more large flake-like compounds of yttrium gather in grain boundaries,performance especially the elongation of the alloy decrease remarkably.