Effect of substitution of minor Nd for Y on mechanical and damping properties of heat-treated Mg-Zn-Y-Zr alloy

This work mainly investigated the effect of Nd substitution on the microstructure, mechanical properties and damping capacity of Mg-Zn-Y-Zr alloy. Obtained results indicate that the phase constituent of the Mg-Zn-Y-Zr alloy and the chemical composition of W-phase vary with the partial substitution of Nd for Y. After solution treatment at 480 °C for 8 h, the secondary phases dissolve into the matrix and ZnZr particles precipitate at grain interiors. During subsequent aging treatment, higher density of β1′ and β2′ phases, Mg12Nd phase, long period stacking ordered (LPSO) and stacking fault (SF) structures precipitate in Mg-Zn-Y-Zr alloy with Nd substitution. The precipitation strengthening further help the ultimate tensile strength and yield strength of the alloy with Nd substitution reach up to 268 MPa and 164 MPa, respectively. The damping capacities of the investigated alloys decrease dramatically after heat treatment. The decline in damping of solution-treated alloys can be ascribed to the increasing number of solute atoms and ZnZr particles. Due to the stacking fault probability, LPSO and SF structures induced by the Nd substitution are believed to be the new damping source to contribute to the damping capacity of Mg-Zn-Y-Zr alloy besides dislocations.