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Title: Dislocation core structures and Peierls stresses of the high-entropy alloy NiCoFeCrMn and its subsystems

Abstract

High entropy alloys (HEAs) have emerged as promising next-generation structural materials. In order to understand the strengthening mechanism in these multicomponent alloys, a theoretical investigation is presented here in the framework of the Peierls-Nabarro (PN) model, which we consider would be appropriate for FCC HEAs due to their homogeneous feature, small lattice distortions and wide dislocation core structures. More importantly, there is no need to differentiate solutes and solvents in this model, which avoids the conceptual difficulties for such alloys. Using PN model, we calculate the dislocation core structures and Peierls stresses of the prototypical NiCoFeCrMn HEA and its six subsystems using the averaged gamma surfaces. The calculated stacking fault widths are in good agreement with available experimental data, and the obtained core structures are important for the future evaluation of the solute-dislocation interaction energies. The Peierls stresses in these multicomponent alloys are found to be much larger than pure FCC metals, and are generally in the same order of magnitude as the critical resolved shear stresses (CRSSs) extrapolated to zero temperature. The results indicate that in contrast to conventional FCC metals, the increased Peierls stresses in MEAs and HEAs could be responsible for their high yield stresses.

Authors:
 [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1528676
Alternate Identifier(s):
OSTI ID: 1530060
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Published Article
Journal Name:
Materials & Design
Additional Journal Information:
Journal Volume: 180; Journal Issue: C; Journal ID: ISSN 0264-1275
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; High-entropy alloy; Medium-entropy alloy; Peierls stress; Dislocation core structure; Solute strengthening

Citation Formats

Liu, Xianglin, Pei, Zongrui, and Eisenbach, Markus. Dislocation core structures and Peierls stresses of the high-entropy alloy NiCoFeCrMn and its subsystems. United States: N. p., 2019. Web. doi:10.1016/j.matdes.2019.107955.
Liu, Xianglin, Pei, Zongrui, & Eisenbach, Markus. Dislocation core structures and Peierls stresses of the high-entropy alloy NiCoFeCrMn and its subsystems. United States. doi:10.1016/j.matdes.2019.107955.
Liu, Xianglin, Pei, Zongrui, and Eisenbach, Markus. Fri . "Dislocation core structures and Peierls stresses of the high-entropy alloy NiCoFeCrMn and its subsystems". United States. doi:10.1016/j.matdes.2019.107955.
@article{osti_1528676,
title = {Dislocation core structures and Peierls stresses of the high-entropy alloy NiCoFeCrMn and its subsystems},
author = {Liu, Xianglin and Pei, Zongrui and Eisenbach, Markus},
abstractNote = {High entropy alloys (HEAs) have emerged as promising next-generation structural materials. In order to understand the strengthening mechanism in these multicomponent alloys, a theoretical investigation is presented here in the framework of the Peierls-Nabarro (PN) model, which we consider would be appropriate for FCC HEAs due to their homogeneous feature, small lattice distortions and wide dislocation core structures. More importantly, there is no need to differentiate solutes and solvents in this model, which avoids the conceptual difficulties for such alloys. Using PN model, we calculate the dislocation core structures and Peierls stresses of the prototypical NiCoFeCrMn HEA and its six subsystems using the averaged gamma surfaces. The calculated stacking fault widths are in good agreement with available experimental data, and the obtained core structures are important for the future evaluation of the solute-dislocation interaction energies. The Peierls stresses in these multicomponent alloys are found to be much larger than pure FCC metals, and are generally in the same order of magnitude as the critical resolved shear stresses (CRSSs) extrapolated to zero temperature. The results indicate that in contrast to conventional FCC metals, the increased Peierls stresses in MEAs and HEAs could be responsible for their high yield stresses.},
doi = {10.1016/j.matdes.2019.107955},
journal = {Materials & Design},
number = C,
volume = 180,
place = {United States},
year = {2019},
month = {6}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1016/j.matdes.2019.107955

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