Development of high-performance Mg alloy via introducing profuse long period stacking ordered phase and stacking faults

Due to low density and other features, magnesium (Mg) alloys are becoming one of key engineering structural materials for aerospace and automotive industries. In the meantime, conventional Mg alloys are limited because of their low mechanical properties, especially at high temperatures. In this study, a new Mg-12Ymm-4Zn (Ymm=Y-rich misch metal, wt%) extruded alloy was prepared by water-cooled mold casting and hot extrusion, and its ultimate tensile strength (UTS) and tensile yield strength (TYS) could reach 314 and 231MPa at 300°C, which were slightly lower than those at room temperature (338 and 278MPa). To date, there is rare report on such high strength for Mg alloys at 300°C, and it has been confirmed that introducing a large volume fraction of long-period stacking ordered (LPSO) phase in combination with nano-spaced stacking faults (SFs) is an effective pathway to develop deformed Mg alloys with high strength at elevated temperatures. In this study, a new high-performance Mg-RE-Zn alloy is developed via introducing a large volume fraction of long-period stacking ordered (LPSO) phase in combination with nano-spaced stacking faults (SFs), and its ultimate tensile strength (UTS) and tensile yield strength (TYS) could reach 314 and 231MPa at 300°C.