Mechanical properties and energy absorption of extruded Mg–2.0Zn–0.3Zr alloy with Y addition

The effects of the rare earth element Y addition on mechanical properties and energy absorption of a low Zn content Mg–Zn–Zr system alloy and the deformation temperature of optimized alloy were investigated by room tensile test, optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscope (TEM). The results show that, after homogenization at 420 °C for 12 h for the as-cast alloys, MgZn phase forms, which decreases the strength of Mg–2.0Zn–0.3Zr alloy with Y content of 0.9 wt%. The tensile strength and elongation of the alloy with a Y addition of 5.8 wt% reach the max value (281 ± 2) MPa and (30.1 ± 0.7) %, respectively; the strength and elongation of Mg–2.0Zn–0.3Zr–0.9Y alloy at the optimized extrusion temperature of 330 °C reach (321 ± 1) MPa and (21.9 ± 0.7) %, respectively. The energy absorption increases with the increase of Y content, the max value reached 0.79 MJ·m⁻³ with Y content of 5.8 wt%, and the energy absorption of Mg–2.0Zn–0.3Zr–0.9Y alloy at the optimized extrusion temperature of 330 °C reaches 0.75 MJ·m⁻³.