Microstructure and high tensile strength of Mg–10Gd–2Y–0.5Zr alloy by solid-state recycling

In general, the tensile strengths of the solid-recycled Mg alloys are increased by T6 treatment after extrusion. For Mg alloy with high rare earth (RE) content, it is difficult to obtain the desired higher tensile strength compared with those extruded ones from the original ingots. In this paper, according to some characteristic of Mg-RE alloys, effect of heat treatment and extrusion temperature on the properties of the recycled Mg–10Gd–2Y–0.5Zr was studied. The results show that the aging response in the recycled specimens is similar to that in as-extruded reference samples. The deformation temperature is increased in order to inhibit Mg24(Gd,Y)5 particles precipitation and realize interfacial bonding between chips. After peak-aged treatment at 225 °C, the GW102K alloy consolidated at 450 °C exhibits excellent tensile strength. It is feasible to obtain the desired tensile properties of the recycled alloys by simultaneously promoting the precipitation of the metastable RE-containing phases and retaining the work-hardening effect during heat treatment.

Research highlights▶ High tensile strength properties of the recycled GW102K alloy are achieved. ▶ The metastable phases and the work-hardening are considered during heat treatment. ▶ Aging response in the recycled alloy is similar to that in as-extruded reference. ▶ Novel paper to obtain high tensile properties of the recycled Mg-RE alloy.