Effects of aging treatment on deformation and fracture of Mg-Gd-Y alloy

To study the effect of aging treatment on precipitation phases and fracture behavior of Mg-Gd-Y alloy, a split Hopkinson pressure bar was used to carry out dynamic compression loading experiments. Fracture morphologies of the magnesium alloy were analyzed by OM and SEM. The experimental results showed that after aging treatment, second-phase precipitates, which increase the strength of the magnesium alloy but decrease its plasticity, were observed in Mg-Gd-Y alloy. Compressive fracture surface of Mg-Gd-Y alloy exhibits typical 45° shear fracture and characteristics of cleavage brittle fracture. Residual second-phase precipitates become the source of fracture and lead to final fracture of materials. Under high strain rate loading, brittle fracture occurs in Mg-Gd-Y alloy treated by peak aging because of age hardening. As to the magnesium alloy treated by over aging or without aging treatment, deformation localization occurs, which causes the final fracture.