Microstructure and mechanical properties of as-cast and extruded Mg-8Li-1Al-0.5Sn alloy

Mg-8Li-1Al-0.5Sn (wt%) alloy was prepared by casting and deformed by hot extrusion in this study. The microstructure and mechanical properties of as-cast and extruded alloys were studied by OM, SEM, XRD, and the tensile test. The results show that the Mg-8Li-1Al-0.5Sn alloy consists of α-Mg (hcp), β-Li (bcc), LiMgAl2, Mg2Sn, Li2MgSn phases. After hot extrusion, the β-Li phase was refined, and Mg2Sn compounds were distributed uniformly in the matrix. The yield strength and ultimate tensile strength of extruded specimen reach to 240 MPa and 322 MPa respectively at room temperature. At 423 K (150 °C), the ultimate tensile strength arrives at 220 MPa for extruded alloy. The strength of Mg-8Li-1Al-0.5Sn alloy is higher than many traditional Mg-Li alloys.