Campus Units

Chemical and Biological Engineering, Materials Science and Engineering, Physics and Astronomy, Ames Laboratory

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

8-1-2020

Journal or Book Title

Acta Materialia

Volume

194

First Page

540

Last Page

546

DOI

10.1016/j.actamat.2020.04.063

Abstract

Phase selection in Ti-Zr-Hf-Al high-entropy alloys was investigated by in-situ high-energy X-ray diffraction, single-crystal X-ray diffraction, and density-functional theory based electronic-structure methods that address disorder and vacancies, predicting formation enthalpy and chemical short-range order (SRO). Samples with varying Al content were synthesized, characterized, and computationally assessed to ascertain the composition-dependent phase selection, as increased Al content often acts as a stabilizer of a body-centered-cubic structure. Equiatomic TiZrHfAl was especially interesting due to its observed bcc superstructure – a variant of γ-brass with 4 vacancies per cell (not 2 as in γ-brass). We highlight how vacancy ordering mediates selection of this variant of γ-brass, which is driven by vacancy-atom SRO that dramatically suppress all atomic SRO. As vacancies are inherent in processing refractory systems, we expect that similar discoveries await in other high entropy alloys or in revisiting older experimental data.

Comments

This is a manuscript of an article published as Singh, Prashant, Shalabh Gupta, Srinivasa Thimmaiah, Bryce Thoeny, Pratik K. Ray, A. V. Smirnov, Duane D. Johnson, and Matthew J. Kramer. "Vacancy-mediated complex phase selection in high entropy alloys." 194 Acta Materialia (2020): 540-546. DOI: 10.1016/j.actamat.2020.04.063. Posted with permission.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Copyright Owner

Acta Materialia Inc.

Language

en

File Format

application/pdf

Available for download on Tuesday, May 17, 2022

Published Version

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