Shock-loading response of Mg-Gd-Y and AZ31 wrought magnesium alloys

The Mg-Gd-Y and AZ31 magnesium alloys were subjected to shock wave loading by using the plain symmetry impact experiment. Then, the uniaxial compression tests were carried out on the recovered shock-deformed samples. Optical microscopy (OM) and transmission electron microscopy (TEM) were used to observe the microstructure. The increased magnitude of the yield strength of the samples for the solutionized and peak-aged Mg-Gd-Y alloy was 21 MPa and 4 MPa, respectively. Therefore, the precipitate phase β' in the peak-aged condition was responsible for the decreased shock strengthening. In contrast, the AZ31 alloy showed a more notable shock-strengthening. The difference of the mechanical behavior between Mg-Gd-Y and AZ31 under shock wave loading was dependent on the discrepancy of deformation mechanisms. The twinning volume fraction for the shock-deformed Mg-Gd-Y alloy was low, indicating that the dominant deformation mechanism was dislocation slip. Whereas, there existed plenty of twinning in the shock deformed AZ31 alloy. The notable shock-strengthening was attributed to the twinning boundary being the obstacles of the dislocation glide in the post-shock reload process.