Microstructure and Tensile Properties of As-Cast Mg-5Sn-4Cu Alloy

Abstract

The microstructure and tensile properties of permanent-mould cast Mg-5wt%Sn-4wt%Cu alloy was investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and tensile test in this paper. The result indicated that the microstructures of the as-cast samples consist of 30-40 μm size primary solidification phase, primary dendrite Mg2(Cu,Sn) which is a network-like interdendritic eutectic intermetallic compounds along grain boundaries and particle like Mg2(Sn,Cu) phases. The Mg-5Sn-4Cu alloy exhibit maximum ultimate tensile strength and yield strength, and the values are 142 MPa and 91 MPa at room temperature. This improved mechanical property is mainly ascribed to the formation of network-like secondary phases of primary dendrite Mg2(Cu,Sn).