Ultrastrong Mg Alloy via Nano-spaced Stacking Faults

Mg alloys are among the lightest alloys but they are usually weak. Here we report a new mechanism to make them ultrastrong while maintaining good ductility. Stacking faults with nanoscale spacing were introduced into a Mg-8.5Gd-2.3Y-1.8Ag-0.4Zr (wt%) alloy by conventional hot rolling, which produced a yield strength of similar to 575 MPa, an ultimate strength of similar to 600 MPa, and a uniform elongation of similar to 5.2 %. Low stacking fault (SF) energy enabled the introduction of a high density of SFs, which impeded dislocation slip and promoted dislocation accumulation. These findings provide guidance for developing Mg alloys with superior mechanical properties.