Ultrahigh Strength Magnesium Sheet Via Stacking Fault Engineering

Historically Mg sheet alloys have been used for aircraft sheet produces, but recent usage is low due to the low strength and limited formability among other concerns.  Here we report a new mechanism to make  ultrastrong and moderately ductile sheet product.  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 ~575 MPa, an ultimate strength of ~600 MPa, and a uniform elongation of ~ 5.2 %.  Low stacking fault energy played an essential role in producing a high density of stacking faults which impeded dislocation slip and promoted dislocation accumulation.  These findings provide guidance for development of Mg alloys with superior mechanical properties.