Effect of stibium on microstructure and properties of Mg-3Sn-1.5Al-1Zn-1.2Si magnesium alloy

The effects of Sb on microstructure and mechanical properties of Mg-3Sn-1.5Al-1Zn-1.2Si magnesium alloy were studied when Sb was added into melt in the form of pure metal with the range of 0-1.8%(mass fraction,similarly hereinafter).The results demonstrate that Sb element and Mg matrix preferentially combine to form Mg3Sb2 phases,the addition of 1.0% Sb has a strong modification for Chinese script morphology Mg2Si phases.Sn can replace Si of Mg2Si then form Sn-rich Mg2(Si,Sn)compound phase,whose physical properties lie between Mg2Si and Mg2Sn.With the increase of Sb content,the elongations of as-cast and extruded alloy decrease,and tensile strengths increase firstly and then decrease,a best combination of strength and plasticity was 1.0% or so.The increase of Sb was beneficial to improve the heat resistance of Mg-3Sn-1.5Al-1Zn-1.2Si alloy.