Effect of isothermal homogenization on microstructure and mechanical properties of the Mg–5Y–4Gd–0.5Zn–0.4Zr alloy

The microstructure and mechanical properties of the Mg–5Y–4Gd–0.5Zn–0.4Zr alloy have been investigated. The results suggested that the 14H long periodic stacking ordered (LPSO) structure was formed during isothermal homogenization. Furthermore, the presence of the 14H LPSO structure resulted in refined microstructure and weak texture while harmful to improve ageing hardening response after hot extrusion. The Mg–5Y–4Gd–0.5Zn–0.4Zr alloy after homogenization for 16 h at 500 °C (as-extruded alloy B) followed by subsequent hot extrusion displayed the highest peak hardness value during ageing at 220 °C. The yield tensile strength and the ultimate tensile strength of the peak-aged alloy B were about 300 MPa and 370 MPa, respectively.