Microstructure and mechanical properties of Mg-10Gd-2Y-0.5Zr alloy recycled by cyclic extrusion compression

Cyclic extrusion compression (CEC) as a new solid-recycling processing was applied to recycle the Mg-10Gd-2Y-0.5Zr alloy. The microstructure and mechanical properties of the recycled alloy were studied. Results showed that after 6-passes CEC processing at 673 K, equiaxed grains of <5 μm were obtained. Meanwhile, deep cracks caused by interfaces decohesion between chips were almost vanished. More second phase particles were observed in the recycled specimens than ingot-processed ones. High temperature CEC of the recycled specimens can accelerate the precipitation of the second phase particles. Ductility of the recycled alloy mainly depended on the degree of elimination of the interfaces between the chips. After 4-passes CEC processing at 723 K, the recycled alloy exhibited a combination of high strength and excellent ductility, and this strength can be ascribed to the grain refinement, uniform distribution of oxide and the precipitation of Mg24(Gd,Y)5, as the second phase particles.