Zheng Yan, Sun Jiaxing, Cheng Kaiming, Wang Jin, Zhan Chengwei, Zhao Jingrui, Wang Xitao, Tang Shouqiu, Zhou Jixue, Zhang Lijun, Du Yong
Shandong Provincial Key Laboratory of High Strength Lightweight Metallic Materials, Advanced Materials Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250014, China.
Laboratory of Materials Phase Equilibria and New Materials Design, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Materials (Basel). 2021 Nov 15;14(22):6892. doi: 10.3390/ma14226892.
The appearance of the ε phase during the welding process can severely weaken the welding strength of dissimilar metals of Mg-Zn-Al alloy systems. An understanding of the accurate phase diagram, especially the equilibrium phase relation around the ε phase, is thus of particular importance. However, the phase interrelation near the -Mg(Al, Zn) phase has not yet been fully studied. In this work, the local phase diagrams of the ε phase and its surrounding phases in the Mg-Zn-Al system are systematically determined by experimental investigation and thermodynamic verification. Five Mg-Zn-Al alloys and one diffusion couple were fabricated and analyzed to get accurate phase constituents and relationships adjacent to ε phase. The current experimental data obtained from Scanning Electron Microscope (SEM), X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), and Electron Probe Micro Analysis (EPMA) were further compared with the thermodynamically computed phase relations around ε phase for verification, showing good agreements. Several important conclusions are drawn based on current experimental work, which can provide supporting information for the follow-up studies on ε phase in the Mg-Zn-Al alloy systems.
在焊接过程中ε相的出现会严重削弱Mg-Zn-Al合金体系异种金属的焊接强度。因此，了解精确的相图，尤其是ε相周围的平衡相关系，就显得尤为重要。然而，-Mg(Al, Zn)相附近的相间关系尚未得到充分研究。在这项工作中，通过实验研究和热力学验证，系统地确定了Mg-Zn-Al体系中ε相及其周围相的局部相图。制备并分析了五种Mg-Zn-Al合金和一个扩散偶，以获得与ε相相邻的精确相组成和关系。将扫描电子显微镜（SEM）、X射线衍射（XRD）、差示扫描量热法（DSC）和电子探针微分析（EPMA）获得的当前实验数据与ε相周围的热力学计算相关系进行了进一步比较以进行验证，结果显示吻合良好。基于当前的实验工作得出了几个重要结论，可为Mg-Zn-Al合金体系中ε相的后续研究提供支持信息。
