Corrosion and mechanical properties of AZ91D magnesium alloy fabricated by solid recycling process

Abstract

We have proposed the "Solid Recycling Process" as a new recycling process for magnesium scraps. In the new process, the recycled materials can be fabricated without melting of scraps, by extruding the scraps. We have investigated corrosion and mechanical properties of the AZ91D magnesium alloy fabricated by this process and clarified the validity of this process. Chemical compositions of the recycled material were in agreement with those of the Japanese Industrial Standard of AZ91D and the contamination levels of Fe, Ni, Cu and Si were low, though Si particles were observed by TEM observation. Mass loss of the recycled material after 72 hour in 3 mass%NaCl solution was about 1.5 × 10-2 kg/m2 which was comparable with that of a virgin ingot. The recycled material showed high strength and larger elongation than a virgin ingot. The feature of the solid recycling process is improvement of mechanical properties by recycling. The improvement of mechanical properties is attributed to grain refinement by hot extrusion.