Effect of Nd on Microstructure and High-Temperature Mechanical Properties of As-cast Mg–Y–Nd–Zn–Zr Alloy

The microstructure evolution and mechanical performance of Mg–5Y–xNd–3Zn–0.6Zr (x = 0, 1, 2, 3) alloys with long period stacking ordered phase (LPSO phase) at elevated temperature (250 °C, 275 °C, and 300 °C) were systematically investigated in this work. The microstructure analyses show that the Mg–5Y–xNd–3Zn–0.6Zr alloys consist of α-Mg with different second phase including LPSO phase and W phase whose volume fraction can be raised by the Nd addition. The Nd addition can refine the α-Mg grain, and the alloy with 3% Nd can refine the grain size by 30% compared to the alloy without Nd. The mechanical properties tests show that the Nd addition can improve the elevated-temperature strength of the alloys, and the optimum mechanical property is achieved at the Nd content of 3%. At the test temperature of 250 °C, 275 °C, and 300 °C, the tensile strength of Mg–5Y–3Nd–3Zn–0.6Zr is 233.3 MPa, 217.0 MPa, and 191.0 MPa, and the elongation of WEZK5330 alloy is 21.6%, 22.2%, and 24.9%, respectively.