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 α-Mg solid solution and β-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 °C, they were about 1.27 times higher than those of Gd-free alloy, which was mainly attributed to the increase of the β-phase and Mg5RE strengthening phase.