Effect of microalloying with Ca and Gd on the hot deformation behavior of AZ31 alloy

Two magnesium alloys of AZX310 and AZE310 were designed through adding 0.5 wt.% Ca and 0.5 wt.% Gd to AZ31, respectively. Tensile tests were performed on the extruded AZX310, AZE310 and AZ31 alloys at the strain rates of 0.1–0.001/s and the temperatures of 150–300 °C. The influence of microalloying with Ca/Gd on the high-temperature mechanical properties of the alloys was investigated. Compared with AZ31, the high-temperature strength of AZX310 and AZE310 was higher, and the elongation was similar. The superior strength of AZX310 and AZE310 was attributed to the effect of grain refinement, Orowan strengthening and the occurrence of dynamic strain aging. Besides, trace amount addition of Ca/Gd promoted the activation of non-basal slip. Through atomic scale characterization, the I₁ stacking faults (SFs) were found in AZX310 and AZE310. These SFs were from the dissociation of < c + a_s > dislocations, where < a_s > was a screw dislocation component.