The Influence of Long-Period Stacking Ordered Structures on Heat Resistance of Mg-12Y-0.6Mn-xZn (x = 0, 4, 6 wt.%) Alloys

Magnesium alloys, noted for their exceptional characteristics such as low density, remarkable specific strength at room temperature, and superior damping capabilities, are progressively emerging as vital engineering structural materials in the aerospace, automotive, and 3C industries. Despite their commendable room-temperature properties, including consistently high strengths and ductility, the relatively poor mechanical performance of magnesium alloys under elevated-temperature conditions limits their applicability in such environments. In this research, we prepared a series of extruded Mg-12Y-0.6Mn-xZn (x = 0, 4, 6 wt.%) alloys enriched with a large volume fraction of long-period stacking ordered (LPSO) structures. We conducted a thorough investigation into the elevated-temperature structural stability of these alloys, exploring the impact of volume fraction on their microstructures, properties, and strengthening mechanisms. Intriguingly, our findings revealed a positive effect of Mn particles on enhancing the elevated-temperature stability of the LPSO phase. Notably, the Mg-12Y-6Zn-0.6Mn (wt.%) alloy demonstrated exceptional ultimate tensile strength (UTS) and tensile yield strength (TYS) of 388 MPa and 258 MPa, respectively, at room temperature, while maintaining UTS and TYS values of 270 MPa and 225 MPa, respectively, at 300 °C. This study provides theoretical support for the application of magnesium alloys in elevated-temperature environments.