Effect of gadolinium on microstructure and mechanical properties of Mg-5Sn-0.5Zn alloy

The effect of rare earth Gd(0.5%-1.5%) additions on microstructure, aging hardening behavior and mechanical properties of Mg-5Sn-0.5Zn alloy(SZ50) was studied. The results showed that the addition of Gd can result in grain refinement of SZ50 alloy and the formation of stick-or strip-shaped Mg ₅G along the boundaries of α-Mg dendrite, and speedup the aging precipitation process. The Mg5Gd phases are smaller in size and distribute uniformly when Gd content is 0.5%. In comparison with SZ50 alloy, addition of Gd causes an increase of tensile strength, but elongation drop off when Gd content is more than 0.5%. When aged at 200°C for 50 h following with extrusion, a satisfied combination of tensile properties and microstructure is obtained in SZ50-0.5Gd alloy.