Mechanical properties and microstructure of AZ31 Mg alloy processed by two-step equal channel angular extrusion

A new equal channel angular extrusion (ECAE) processing, two-step ECAE, was applied to control the microstructure and mechanical properties of AZ31 Mg alloy. The ultra-fine grain size of 0.5 μm has been produced, and both the ductility and yield stress of the alloy were significantly increased after the processing, which is ascribed to grain refinement as well as incomplete dynamic recovery and recrystallization during the second-step ECAE at 453 K.