Designing High Entropy Alloys with Dual fcc and bcc Solid-Solution Phases: Structures and Mechanical Properties
High entropy alloys (HEAs) with a single fcc phase are usually ductile but not strong, while HEAs with a single bcc phase have high strength but low ductility. Therefore, the combination of fcc and bcc phases was adopted to optimize the mechanical properties. Based on a latest data collection of reported HEAs with a single fcc phase, with dual fcc and bcc phases, and with a single bcc phase, the current work shows that the average valence electron concentration (VEC) and its standard deviation (δVEC) can describe quantitatively phase selection between the fcc and bcc phases in HEAs. Highest (lowest) hardness, highest (lowest) strength, and lowest (highest) ductility were found at the same critical value of VEC* ≈ 6.13 (δVEC* ≈ 0.207), which corresponds to the HEA with a single bcc (fcc) phase. The current work provides some quantitative rules for designing HEAs with dual fcc and bcc phases as well as modulating strength and ductility.
This work was done under the Huo Yingdong Young Teacher Fund (Grant No. 151048), the Science Fund for Distinguished Young Scholars from Shaanxi province (Grant No. 2018-JC007), and the Fundamental Research Funds for the Central Universities. The authors appreciate Dr. Vipul Bhardwaj for reading and polishing the manuscript.
- 13.M.C. Gao, C. Zhang, P. Gao, F. Zhang, L.Z. Ouyang, M. Widom, and J.A. Hawk: Curr. Opin: Solid State Mater. Sci., 2017, vol. 21, pp. 238–51.Google Scholar
- 39.Y.M. Tan, J.S. Li, Z.W. Tang, J. Wang, and H.C. Kou: submitted for publication.Google Scholar
- 47.M.C. Troparevsky, J.R. Morris, P.R.C. Kent, A.R. Lupini, and G.M. Stocks: Phys. Rev. X, 2015, vol. 5, p. 011041.Google Scholar
- 64.C.J. Tong, Y.L. Chen, and J.W. Yeh: Metall. Mater. Trans. A, 2006, vol. 36A, pp. 1263–71.Google Scholar
- 66.N. Liu, C. Chen, I.T.H. Chang, P. J. Zhou, and X.J. Wang: Materials, 2018, vol. 11, pp. 1290, 1–11.Google Scholar