Campus Units

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

Document Type

Article

Publication Version

Submitted Manuscript

Publication Date

5-1-2020

Journal or Book Title

Acta Materialia

Volume

189

First Page

248

Last Page

254

DOI

10.1016/j.actamat.2020.02.063

Abstract

Multi-principal-element alloys, including high-entropy alloys, experience segregation or partially-ordering as they are cooled to lower temperatures. For Ti0.25CrFeNiAlx, experiments suggest a partially-ordered B2 phase, whereas CALculation of PHAse Diagrams (CALPHAD) predicts a region of L21+B2 coexistence. We employ first-principles density-functional theory (DFT) based electronic-structure approach to assess stability of phases of alloys with arbitrary compositions and Bravais lattices (A1/A2/A3). In addition, DFT-based linear-response theory has been utilized to predict Warren-Cowley short-range order (SRO) in these alloys, which reveals potentially competing long-range ordered phases. The resulting SRO is uniquely analyzed using concentration-waves analysis for occupation probabilities in partially-ordered states, which is then be assessed for phase stability by direct DFT calculations. Our results are in good agreement with experiments and CALPHAD in Al-poor regions (x ≤ 0.75) and with CALPHAD in Al-rich region (0.75 ≤ x ≤ 1), and they suggest more careful experiments in Al-rich region are needed. Our DFT-based electronic-structure and SRO predictions supported by concentration-wave analysis are shown to be a powerful method for fast assessment of competing phases and their stability in multi-principal-element alloys.

Comments

This is a manuscript of an article published as Singh, Prashant, A. V. Smirnov, Aftab Alam, and Duane D. Johnson. "First-principles prediction of incipient order in arbitrary high-entropy alloys: exemplified in Ti0.025CrFeNiAlx." 189 Acta Materialia (2020): 248-254. DOI: 10.1016/j.actamat.2020.02.063. 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 Thursday, March 10, 2022

Published Version

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