Superior Corrosion Resistance and Mechanical Properties of a Mg Alloy Recycled by Solid-State Process

Superior mechanical properties of the recycled specimen by solid-state recycling were introduced at first. AZ31 Mg machined chips were recycled by extrusion at 673 K with the different extrusion ratios. The oxide contaminants were dispersed more uniformly in the recycled specimen with the high extrusion ratio (1600:1). There was a remarkable increase in tensile strength and 0.2% yield stress for the recycled specimen with the high extrusion ratio compared with an extrusion reference subjected to the same deformation history. Next, superior corrosion resistance of the recycled specimen was introduced. The recycled specimen with low extrusion ratio (45:1) possessed superior corrosion resistance compared with the extrusion reference. The enhancement of corrosion resistance for the recycled specimens was attributed to the presence of oxide contaminants which were distributed parallel to the extrusion direction.

Mechanical properties of AZ31 Mg alloy recycled by severe deformation

AZ31 Mg machined chips were recycled by extrusion at 673 K with a low extrusion ratio of 45:1 and a high extrusion ratio of 1600:1. Oxide contaminants were dispersed more uniformly in the recycled specimen with the high extrusion ratio than in that with the low extrusion ratio. In tensile tests, the recycled specimens with the high extrusion ratio showed about 50% higher 0.2% yield stress and about 20% higher tensile strength compared with those of the reference specimens, which were the extruded AZ31 Mg blocks under the same conditions as the recycled specimens. The improvement of the tensile properties was attributed not only to the small grain size, but also to the dispersed oxide contaminants.