Effect of Gd on the Microstructure and Mechanical Properties of Mg-Sn-Zn-Al Alloy

The effect of Gd addition on the microstructures and mechanical properties of Mg-5Sn-Zn-Al alloy was investigated with variations of Gd contents. These results show that adding Gd can effectively refine the grain size and growth. In addition, the solubility of Gd increases the lattice constants ofα-Mg phase. Accordingly, the tensile properties of the as-cast Mg-5Sn-Zn-Al alloy are improved by the addition of Gd. The Mg-5Sn-Zn-Al-0.4Gd exhibits the highest tensile properties, and the values of the yield and ultimate tensile strength and elongation are 111 MPa, 188 MPa and 18.0%, respectively.