This work investigates the effect of activating and accumulating prismatic <a> dislocations on ductility of a Mg-7.37Gd-3.1Y-0.27Zr (GW83K) alloy at sub-zero temperatures. It is found that the prismatic <a> dislocations were more easily activated with decreasing temperature due to the lowering of CRSS _{prismatic <a>} / CRSS _{basal <a>} ratio in this alloy. Increasing the proportion of prismatic <a> dislocations shows limited effect on improving the ductility of GW83K alloy in the early-stage deformation at sub-zero temperatures, because the prismatic <a> dislocations cannot accommodate c-axis deformation. However, with the formation of low-angle grain boundaries rotating along [0001] axis induced by the accumulation of prismatic <a> dislocations, the GW83K alloy can perform a much better ductility in the late-stage deformation. Such a finding provides a new perspective on understanding the contribution of prismatic <a> dislocations to ductility in Mg alloys.

这项工作研究了在零度以下温度下激活和累积棱柱 < a > 位错对 Mg-7.37Gd-3.1Y-0.27Zr (GW83K) 合金延展性的影响。结果表明，由于该合金中 CRSS 棱柱 <a> / CRSS 基底 <a> 比值降低_，棱柱<a>位_错更容易随着温度的降低而_被激活_。增加棱柱 < a > 位错的比例对提高 GW83K 合金在零下温度下早期变形的延展性显示出有限的效果，因为棱柱 < a > 位错不能容纳c-轴变形。然而，随着棱柱<a>位错的积累诱导长[0001]轴旋转的小角度晶界的形成，GW83K合金在后期变形中可以表现出更好的延展性。这一发现为理解棱柱 < a > 位错对镁合金延展性的贡献提供了新的视角。