ABSTRACT
The surface mechanical attrition treatment was taken to fabricate the gradient structure in AZ31 magnesium alloy sheet. Recently, it has been evidenced that superior combination between strength and ductility could be achieved through gradient microstructure (GS), where the grain sizes are gradually increased from nanoscale at surface to microscale at center core along thickness direction. In current investigation, the GS generated through surface mechanical attrition treatment (SMAT) has been employed to improve the mechanical properties of magnesium alloys. This strategy is designed to take advantage of the reduction in yield stress anisotropy due to grain refinement, together with the dislocation accumulation in small grains due to strain gradient and compatible deformation. A dual gradient microstructure was obtained in AZ31 magnesium alloy through SMAT processing, where the microstructural size and crystallographic orientation change gradually along thickness. The deformation mechanisms and corresponding influence to mechanical properties are investigated.
