**5. Conclusions**

1. The microstructure of the cast ZK60 alloy was composed of an α-Mg phase and large second-phase particles (MgZn2), which mainly deposited along the grain boundaries, and a Zr-rich region existed in the central area of the grains. The grain boundaries and their adjacent regions (noted as grain boundary regions) had relatively higher Mg contents.


**Author Contributions:** Conceptualization, Z.L. and Y.Q.; methodology, Z.L.; software, Z.L., Z.P. and K.Q.; validation, Y.Q., K.Q. and X.G.; formal analysis, Z.L.; investigation, Z.L.; resources, Z.L., Z.P. and H.L.; data curation, Z.L., Z.P., and H.L.; writing—original draft preparation, Z.L.; writing—review and editing, K.Q., Y.Q., and X.G.; visualization, Z.L.; supervision, Y.Q.; funding acquisition, Y.Q. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors are thankful for the analysis support of the Key Laboratory of Material Chemistry for Energy Conversion and Storage and the Analytical and Testing Center, Huazhong University of Science and Technology.

**Conflicts of Interest:** The authors declare no conflict of interest.
