Effect of Deformation Conditions on Dynamic Mechanical Behavior of a Mg–Gd-Based Alloy

The effect of the deformation temperature and strain rate on the dynamic mechanical behavior of an extruded Mg-8Gd-4Y-Nd-Zr alloy plate is investigated using optical microscopy, scanning electron microscopy, x-ray diffraction and the split Hopkinson pressure bar methods. The alloy exhibits excellent dynamic compressive strength both at room temperature and high temperatures. The compressive strength of the alloy can reach 569 MPa, 635 MPa and 567 MPa at the deformation conditions of room temperature/2317 s−1, 200°C/1659 s−1, and 300°C/1581 s−1, respectively. The excellent mechanical properties of the alloy at different temperatures are mainly due to the stable rare earth-rich particles and the dynamic precipitates formed at the grain boundaries during compression. Cleavage planes and dimples are the main features of the fracture surface. The number of dimples increases as the deformation temperature increases, while the proportion of cleavage planes decreases with increasing temperature. However, the fracture characteristics are distinct in different regions. A large number of cleavage surfaces can also be observed in certain areas, where the cleavage cracks are easy to propagate, even if the sample is compressed at elevated temperatures.