Impact of Mg addition on solidification behaviour of Al-7% Si alloy

Abstract

The impact of Mg addition to Al7Si alloy is investigated using thermal and image analyses. It is shown that Mg expands α-Al solidification range and eutectic forms over a thermal range. For alloys containing less than 0·6%Mg, differential scanning calorimetry analysis and thermodynamic calculations are incapable of predicting the formation of Mg2Si phase during solidification. Furthermore, Mg addition leads to the formation of greater percentage of α-Al primary phase which is beneficial during semisolid processing of hypoeutectic Al–Si alloys.