**4. Conclusions**

In this work, we designed and prepared single BCC Zr-Nb-Ti MEAs, and then performed the Fe-ion irradiation experiments to examine their irradiation resistance. The nanoindentation experiment and microstructural characterization indicated excellent properties of the fabricated materials in terms of irradiation resistance compared with traditional alloys. The main conclusions are summarized as follows:

(1) The tensile tests showed that the MEAs have a good combination of strength and toughness. At room temperature, the yield strength of these three alloys, Zr40Nb35Ti25, Zr50Nb35Ti15, and Zr60Nb35Ti5, is 943, 903, and 1285 MPa, and the fracture strain is 17.5%, 14%, and 11%, respectively. At 400 ◦C, the fracture strain increases to 28%, 25%, and 20.5%, respectively. The fracture morphology shows that the fracture mode is the ductile fracture.


**Author Contributions:** Conceptualization, Z.S., T.S. and D.L.; methodology, Z.S., Z.Q., S.H., P.J. and J.L.; formal analysis, Z.S., Z.Q. and S.H.; resources, T.S. and D.L.; data curation, Z.S., Z.Q., S.H., P.J. and J.L.; writing—original draft preparation, Z.S.; writing—review and editing, Z.S., P.J., T.S. and D.L.; project administration, T.S. and D.L.; funding acquisition, T.S. and D.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Natural Science Foundation of China (Grant Nos. 12162023, 51365029, 12175288 and U1832206) and the International Cooperation project of Gansu Province under gran<sup>t</sup> number (Grant No. 20YF8WA064).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

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