Enhanced corrosion properties of pure Mg and AZ31 Mg alloy recycled by solid-state process

The corrosion behaviors of pure Mg and AZ31 Mg alloy recycled by a solid-state process were investigated by salt (5 wt.% NaCl solution) immersion tests, and were compared with those of an ingot reference and an extrusion reference subjected to the same deformation history. The recycled specimen possessed superior corrosion resistance compared with the reference ones, contrary to anticipated apprehension. The enhancement of corrosion resistance for the recycled specimens was attributed to the presence of dense oxide contaminants which were distributed parallel to the extrusion direction. The addition of Al accelerated the enhancement of corrosion resistance by solid-state recycling. This suggests that the capacity of the oxides as corrosion barriers depends their elemental content.