Microstructures and mechanical properties of as-cast Mg-5Y-3Nd-Zr-xGd (x=0, 2 and 4 wt.%) alloys

Mg-5Y-3Nd-0.6Zr-xGd (x = 0, 2 and 4 wt.%) alloys were prepared by metal mould casting technique, the structures and mechanical properties were investigated. The alloys were mainly composed of alpha-Mg solid solution and beta-phase. With increasing Gd content, Mg5RE phase increased and the grain was refined. The Mg-5Y-3Nd-2Gd-0.6Zr alloy exhibited highest ultimate tensile strength and Mg-5Y-3Nd-0.6Zr alloy showed highest yield strength at room temperature. With increasing amount of Gd, the thermal resistance was improved. The Mg-5Y-3Nd-4Gd-0.6Zr alloy exhibited highest UTS and YS at 250 degrees C, they were about 1.27 times higher than those of Gd-free alloy, which was mainly attributed to the increase of the beta-phase and Mg5RE strengthening phase.