The effect of deformation processing on the microstructure and mechanical properties of Mg-Y-Gd-Zr alloy

Abstract

Microstructure and properties of the magnesium alloy Mg-3.5Y-5.5Gd-0.3Zr (wt. %) have been studied after hot extrusion and rotary swaging. The effect of the deformation method on the kinetics of the decomposition of the magnesium supersaturated solid solution at 200 °C has been investigated. The mechanical properties of the alloy at room temperature have been determined both after deformation and after additional strengthening aging. It has been shown that deformation leads to grain refinement of the cast structure from ~50 μm to ~9 μm after hot extrusion and to ~16 μm after rotary swaging, respectively. After deformation, the alloy can be additionally strengthened by the aging treatment, with hot extrusion and, to a greater extent, rotary swaging accelerating the decomposition of the supersaturated magnesium solid solution. Hot extrusion enhances both strength and plastic properties, while rotary swaging provides the highest achievement of strength properties with a decrease in ductility. After rotary swaging and aging, the alloy exhibited an ultimate tensile strength of ~485 MPa, yield strength of ~460 MPa, and elongation of ~4.5%.