**4. Conclusions**

The microstructure evolutions and mechanical properties of a Mg-3.5Al-1.7Ca-0.4Mn (wt %) alloy during ECAP at different processing numbers and temperatures were systematically investigated. The main conclusions can be drawn as follows:


**Author Contributions:** A.M., H.L. and J.J. designed the project and guided the research; C.W., J.S. and H.L. prepared the manuscript; C.W., H.H. and Z.Y. performed the experiment and analyzed the data; X.Z., H.H. and C.W. prepared the figures; A.M., H.L. and J.J. reviewed the manuscript.

**Funding:** The authors are grateful to the financial aid from the Natural Science Foundation of Jiangsu Province of China (BK20160869), the National Natural Science Foundation of China (51774109 and 51501039), the Fundamental Research Funds for the Central Universities (2018B48414), the Key Research and Development Project of Jiangsu Province of China (BE2017148), and the Nantong Science and Technology Project (JC2018109).

**Data Availability:** The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study.

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