Microstructural evolution and tensile properties features of wrought Mg-Nd alloy

Effects of various deformed conditions on microstructures and tensile properties of Mg-2.5Nd-0.5Zn-0.5Zr wt% (Mg-Nd) alloy were investigated. Mg-Nd alloy as-extruded exhibit higher strength and better ductility compared to that of as-T6 condition, while its ratio of yield strength to ultimate strength is enhanced from 0.58 to 0.87. With increasing of the extrusion strain rate, both yield strength and ultimate strength increase at the constant extrusion temperature. Nevertheless, the ductility obeys the opposite regulation. At the same extrusion strain rate, both yield strength and ultimate strength decrease with increasing of the extrusion temperature. Fine Mg₉Nd compound particles precipitated in the grain boundaries refine the grains resulting in improving the mechanical properties of as-extruded Mg-Nd alloy. The alloy superplasticity behavior was also exploited in the tensile tests at high temperatures. The results depict that 375°C is the optimal deformation temperature, while the elongation amounts to 329% at the strain rate of 1 × 10^-2s^-1. The fracture surface indicates that mechanism of the superplasticity of Mg-Nd alloy is controlled by the grain boundary sliding accommodated with cavities interlinked.