Two modes of screw dislocation glide in fcc single-phase concentrated alloys
Abstract
Concentrated solid solution alloys (CSSAs), including medium- and high-entropy alloys, are currently being considered as prospective materials in many applications. The behavior of CSSAs under different conditions, including mechanical loading, differs from that of conventional alloys and has been the subject of intensive study by different techniques. In many cases, their behavior is treated by modifying solid solution hardening models, which, in principle, does not reflect many important features of CSSAs where the distinction between solute and solvent atoms is not clear. In this work, we report the results of an atomic-scale study of ½<110>{111} screw dislocation motion in an fcc equiatomic Ni-Fe alloy. Molecular dynamics simulations demonstrate that the dislocation has two distinctive modes for glide. At lower stress, dislocations move in a very rough manner that cannot be described as continuous glide but rather as jerky motion through a set of obstacles. At high stress, they glide in a manner similar to lattice friction-controlled conditions in single component systems. The stress for the transition between modes depends on the dislocation segment length and temperature. As a result, at 300 K, the flow stress saturates at ~130 MPa for lengths above ~140 |b| (b is the Burgers vector).
- Authors:
-
[1];
[3]
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Texas A & M Univ., College Station, TX (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, 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)
- OSTI Identifier:
- 1493147
- Alternate Identifier(s):
- OSTI ID: 1636982
- Grant/Contract Number:
- AC05-00OR22725
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Acta Materialia
- Additional Journal Information:
- Journal Volume: 164; Journal Issue: C; Journal ID: ISSN 1359-6454
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; Dislocation dynamics; Phonon drag; NiFe alloys; Concentrated alloys; Molecular dynamics
Citation Formats
Osetsky, Yuri N., Pharr, George M., and Morris, James R. Two modes of screw dislocation glide in fcc single-phase concentrated alloys. United States: N. p., 2018.
Web. doi:10.1016/j.actamat.2018.11.020.
Osetsky, Yuri N., Pharr, George M., & Morris, James R. Two modes of screw dislocation glide in fcc single-phase concentrated alloys. United States. https://doi.org/10.1016/j.actamat.2018.11.020
Osetsky, Yuri N., Pharr, George M., and Morris, James R. Mon .
"Two modes of screw dislocation glide in fcc single-phase concentrated alloys". United States. https://doi.org/10.1016/j.actamat.2018.11.020. https://www.osti.gov/servlets/purl/1493147.
@article{osti_1493147,
title = {Two modes of screw dislocation glide in fcc single-phase concentrated alloys},
author = {Osetsky, Yuri N. and Pharr, George M. and Morris, James R.},
abstractNote = {Concentrated solid solution alloys (CSSAs), including medium- and high-entropy alloys, are currently being considered as prospective materials in many applications. The behavior of CSSAs under different conditions, including mechanical loading, differs from that of conventional alloys and has been the subject of intensive study by different techniques. In many cases, their behavior is treated by modifying solid solution hardening models, which, in principle, does not reflect many important features of CSSAs where the distinction between solute and solvent atoms is not clear. In this work, we report the results of an atomic-scale study of ½<110>{111} screw dislocation motion in an fcc equiatomic Ni-Fe alloy. Molecular dynamics simulations demonstrate that the dislocation has two distinctive modes for glide. At lower stress, dislocations move in a very rough manner that cannot be described as continuous glide but rather as jerky motion through a set of obstacles. At high stress, they glide in a manner similar to lattice friction-controlled conditions in single component systems. The stress for the transition between modes depends on the dislocation segment length and temperature. As a result, at 300 K, the flow stress saturates at ~130 MPa for lengths above ~140 |b| (b is the Burgers vector).},
doi = {10.1016/j.actamat.2018.11.020},
journal = {Acta Materialia},
number = C,
volume = 164,
place = {United States},
year = {Mon Nov 12 00:00:00 EST 2018},
month = {Mon Nov 12 00:00:00 EST 2018}
}
Search WorldCat to find libraries that may hold this journalWeb of Science