Fabrication of a high strength Mg–11Gd–4.5Y–1Nd–1.5Zn–0.5Zr (wt%) alloy by thermomechanical treatments

Abstract

A high strength Mg–11Gd–4.5Y–1Nd–1.5Zn–0.5Zr (wt%) alloy has been successfully fabricated via hot extrusion, cold rolling and ageing treatment. The alloy exhibits an average 0.2% proof stress (YS) of 481.6±19.9 MPa, an average ultimate tensile strength (UTS) of 517.4±27.5 MPa and an average elongation to failure of 2.0±0.4% at room temperature. The best mechanical property obtained in the present study has a YS of 502.0 MPa, an UTS of 546.8 MPa and an elongation to failure of 2.6%. The high strength of this alloy is attributed to the fine grains, stacking faults (SFs), long period stacking ordered (LPSO) phase, and precipitates of Mg5RE phase at grain boundaries and of β′ phase inside the grains. Cold rolling improves the mechanical properties and enhances the ageing hardening response, but decreases the ductility. Two texture components are found simultaneously in the deformed alloy. One is the typical Mg–RE texture and another one is the unusual prismatic texture.