Microstructure and mechanical properties in cast magnesium–neodymium binary alloys

The microstructure, tensile properties and creep behavior of three binary magnesium–neodymium (Mg–Nd) based alloys were investigated. The microstructure of all the alloys consists of the dendritic α-Mg matrix and a divorced eutectic Mg12Nd. With the increase of neodymium addition, the volume fraction of the Mg12Nd phase increases and an interphase network is visible with 4 wt% of neodymium addition. The addition of Nd to Mg causes significant improvement of creep properties and the creep resistance increases with the increase of Nd addition, which is account for by the combination of precipitation and solid solution hardening. For the Mg–2 wt%Nd alloy, a stress exponent of 4.5 and an apparent activation energy of 151.8 kJ/mol were obtained at 175 °C/50–90 MPa and 150–225 °C/70 MPa, respectively, suggesting that the mechanism responsible for creep in the present investigation is dislocation climb.