ABSTRACT

In the present study, the structural evolution of the precipitates in Mg-Gd-Y-Zr alloy is investigated by means of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The linearly aligned morphology of ${\text{β}}^{\mathrm{\prime }}$ phases connected by bridging ${\text{β}}_M$ phase in one of the three equivalent crystal directions of $\left[10\overline{1}0\right]$ is formed from defect-free randomly distributed ${\text{β}}^{\mathrm{\prime }}$phases. Considering the significant strengthening effect of ${\text{β}}^{\mathrm{\prime }}$ precipitates, a novel perspective of investigating the induced strain field measured by geometric phase analysis (GPA) is conducted. The reducing value of the strain field accounts for a slight decrease in hardness after peak-ageing. Merging and rearrangement of ${\text{β}}^{\mathrm{\prime }}$ precipitates are found to release the strain field.

摘要

在本研究中，通过高角度环形暗场扫描透射电子显微镜（HAADF-STEM）研究了 Mg-Gd-Y-Zr 合金中析出物的结构演变。线性排列的形态${\text{β}}^{\mathrm{\text{'}}}$ 通过桥接连接的相 ${\text{β}}_{米}$ 在三个等效晶体方向之一的相位 $\left[10\overline{1}0\right]$ 由无缺陷随机分布形成 ${\text{β}}^{\mathrm{\text{'}}}$阶段。考虑到显着的强化效果${\text{β}}^{\mathrm{\text{'}}}$沉淀物，进行了研究通过几何相分析（GPA）测量的诱导应变场的新视角。应变场的减小值解释了峰值时效后硬度的轻微下降。合并与重组${\text{β}}^{\mathrm{\text{'}}}$发现沉淀物释放应变场。