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Title: Atomic-scale dynamics of edge dislocations in Ni and concentrated solid solution NiFe alloys

Abstract

Single-phase concentrated solid solution alloys (CSAs), including high entropy alloys, exhibit excellent mechanical properties compared to conventional dilute alloys. However, the origin of this observation is not clear yet because the dislocation properties in CSAs are poorly understood. In this work, the mobility of a <110>{111} edge dislocation in pure Ni and equiatomic solid solution Ni 0.5Fe 0.5 (NiFe) is studied using molecular dynamics simulations with different empirical potentials. The threshold stress to initiate dislocation movement in NiFe is found to be much higher compared to pure Ni. The drag coefficient of the dislocation motion calculated from the linear regime of dislocation velocities versus applied stress suggests that the movement of dislocations in NiFe is strongly damped compared to that in Ni. The present results indicate that the mobility of edge dislocations in fcc CSAs are controlled by the fluctuations in local stacking fault energy caused by the local variation of alloy composition.

Authors:
 [1];  [1];  [1];  [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. (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)
OSTI Identifier:
1361346
Alternate Identifier(s):
OSTI ID: 1417114
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Alloys and Compounds
Additional Journal Information:
Journal Volume: 701; Journal Issue: C; Journal ID: ISSN 0925-8388
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; concentrated solid solution alloys; Edge dislocation; dislocation velocity; NiFe alloys; molecular dynamics simulations

Citation Formats

Zhao, Shijun, Osetsky, Yuri N., Zhang, Yanwen, and Univ. of Tennessee, Knoxville, TN. Atomic-scale dynamics of edge dislocations in Ni and concentrated solid solution NiFe alloys. United States: N. p., 2017. Web. doi:10.1016/j.jallcom.2017.01.165.
Zhao, Shijun, Osetsky, Yuri N., Zhang, Yanwen, & Univ. of Tennessee, Knoxville, TN. Atomic-scale dynamics of edge dislocations in Ni and concentrated solid solution NiFe alloys. United States. doi:10.1016/j.jallcom.2017.01.165.
Zhao, Shijun, Osetsky, Yuri N., Zhang, Yanwen, and Univ. of Tennessee, Knoxville, TN. Thu . "Atomic-scale dynamics of edge dislocations in Ni and concentrated solid solution NiFe alloys". United States. doi:10.1016/j.jallcom.2017.01.165. https://www.osti.gov/servlets/purl/1361346.
@article{osti_1361346,
title = {Atomic-scale dynamics of edge dislocations in Ni and concentrated solid solution NiFe alloys},
author = {Zhao, Shijun and Osetsky, Yuri N. and Zhang, Yanwen and Univ. of Tennessee, Knoxville, TN},
abstractNote = {Single-phase concentrated solid solution alloys (CSAs), including high entropy alloys, exhibit excellent mechanical properties compared to conventional dilute alloys. However, the origin of this observation is not clear yet because the dislocation properties in CSAs are poorly understood. In this work, the mobility of a <110>{111} edge dislocation in pure Ni and equiatomic solid solution Ni0.5Fe0.5 (NiFe) is studied using molecular dynamics simulations with different empirical potentials. The threshold stress to initiate dislocation movement in NiFe is found to be much higher compared to pure Ni. The drag coefficient of the dislocation motion calculated from the linear regime of dislocation velocities versus applied stress suggests that the movement of dislocations in NiFe is strongly damped compared to that in Ni. The present results indicate that the mobility of edge dislocations in fcc CSAs are controlled by the fluctuations in local stacking fault energy caused by the local variation of alloy composition.},
doi = {10.1016/j.jallcom.2017.01.165},
journal = {Journal of Alloys and Compounds},
number = C,
volume = 701,
place = {United States},
year = {Thu Jan 19 00:00:00 EST 2017},
month = {Thu Jan 19 00:00:00 EST 2017}
}

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