Microstructural characterizations and mechanical properties of Mg-8Sn-1Al-1Zn-xCu alloys

Abstract

Microstructural characterization and mechanical properties of as-cast Mg-8Sn-1Al-1Zn-xCu (x=0wt%, 1wt%, 1.5wt% and 2.0wt%) alloys were studied by OM, Pandat software, XRD, SEM, DSC and a standard universal testing machine. The experimental results indicate that adding Cu to TAZ811 alloy leads to the formation of the AlMgCu and Cu3Sn phases. Tensile tests indicate that yield strength increases firstly and then decreases with increasing Cu content. The alloy with the addition of 1.5wt% Cu exhibits optimal mechanical properties among the studied alloys. The improved mechanical properties can be ascribed to the second phase strengthening and fine-grain strengthening mechanisms resulting from the more dispersed second phases and smaller grain size, respectively. The decrease in ultimate tensile strength and elongation of TAZ811-2.0wt% Cu alloy at room temperature is ascribed to the formation of continuous AlMgCu and coarse Mg2Sn phases in the liquid state.