**4. Conclusions**

The following conclusions can be drawn based on the present investigation.

(1) Di fferent shapes of flow stress curves were obtained at di fferent strain rates, and the shape change was explained by microstructure observations. At 10 s<sup>−</sup>1, the overall volume fraction of recrystallized grains was not high. Dynamic recovery dominated, and therefore, it showed monotonically increasing dynamic recovery type stress–strain curves. While at 0.01 s<sup>−</sup>1, the dynamic recrystallization was completed, and dynamic recrystallization dominated. Thus, it showed single-peaked dynamic recrystallization type stress–strain curves.


**Author Contributions:** Writing-original draft preparation, R.C.; writing-review & editing, H.X.; funding acquisition, M.W. and J.L.

**Funding:** This study was funded by the National Natural Science Foundation of China (51435007), the Natural Science Foundation of Hubei province (2017CFB587), the State Key Laboratory of Materials Processing and Die & Mould Technology in Huazhong University of Science and Technology (P2020-015), the Outstanding Young Scientific &Technological Innovation Team Plan of Colleges and Universities in Hubei Province (T201518), the Hubei Key Laboratory of Automotive Power Train and Electronic Control in Hubei University of Automotive Technology (ZDK1201601), and the Doctoral Scientific Research Fund of Hubei University of Automotive Technology (BK201901).

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