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Title: The core structure and recombination energy of a copper screw dislocation: a Peierls study

The recombination process of dislocations is central to cross-slip, and transmission through Σ3 grain boundaries among other fundamental plastic deformation processes. Despite its importance, a detailed mechanistic understanding remains lacking. In this paper, we apply a continuous dislocation model, inspired by Peierls and Nabarro, complete with an ab-initio computed -surface and continuous units of infinitesimal dislocation slip, towards computing the stress-dependent recombination path of both an isotropic and anisotropic Cu screw dislocation. Under no applied stress, our model reproduces the stacking fault width between Shockley partial dislocations as predicted by discrete linear elasticity. Upon application of a compressive Escaig stress, the two partial dislocations coalesce to a separation of ~|b|. Upon increased loading the edge components of each partial dislocation recede, leaving behind a spread Peierls screw dislocation, indicating the recombined state. We demonstrate that the critical stress required to achieve the recombined state is independent of the shear modulus. Rather the critical recombination stress depends on an energy difference between an unstable fault energy (γτ) and the intrinsic stacking fault energy (γτ-γisf). We report recombination energies of ΔW = 0.168 eV/Å and ΔW = 0.084 eV/Å, respectively, for the Cu screw dislocation within isotropic and anisotropic media. Finally, wemore » develop an analytic model which provides insight into our simulation results which compare favourably with other (similar) models.« less
Authors:
 [1] ;  [1] ;  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Univ. of California, Santa Barbara, CA (United States)
Publication Date:
Report Number(s):
LA-UR-17-20638
Journal ID: ISSN 1478-6435
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Philosophical Magazine (2003, Print)
Additional Journal Information:
Journal Name: Philosophical Magazine (2003, Print); Journal Volume: 97; Journal Issue: 25; Journal ID: ISSN 1478-6435
Publisher:
Taylor & Francis
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Laboratory Directed Research and Development (LDRD) Program
Contributing Orgs:
Univ. of California, Santa Barbara, CA (United States)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; cross-slip; anisotropy; Peierls-Nabarro model
OSTI Identifier:
1369196

Szajewski, B. A., Hunter, A., and Beyerlein, I. J.. The core structure and recombination energy of a copper screw dislocation: a Peierls study. United States: N. p., Web. doi:10.1080/14786435.2017.1328138.
Szajewski, B. A., Hunter, A., & Beyerlein, I. J.. The core structure and recombination energy of a copper screw dislocation: a Peierls study. United States. doi:10.1080/14786435.2017.1328138.
Szajewski, B. A., Hunter, A., and Beyerlein, I. J.. 2017. "The core structure and recombination energy of a copper screw dislocation: a Peierls study". United States. doi:10.1080/14786435.2017.1328138. https://www.osti.gov/servlets/purl/1369196.
@article{osti_1369196,
title = {The core structure and recombination energy of a copper screw dislocation: a Peierls study},
author = {Szajewski, B. A. and Hunter, A. and Beyerlein, I. J.},
abstractNote = {The recombination process of dislocations is central to cross-slip, and transmission through Σ3 grain boundaries among other fundamental plastic deformation processes. Despite its importance, a detailed mechanistic understanding remains lacking. In this paper, we apply a continuous dislocation model, inspired by Peierls and Nabarro, complete with an ab-initio computed -surface and continuous units of infinitesimal dislocation slip, towards computing the stress-dependent recombination path of both an isotropic and anisotropic Cu screw dislocation. Under no applied stress, our model reproduces the stacking fault width between Shockley partial dislocations as predicted by discrete linear elasticity. Upon application of a compressive Escaig stress, the two partial dislocations coalesce to a separation of ~|b|. Upon increased loading the edge components of each partial dislocation recede, leaving behind a spread Peierls screw dislocation, indicating the recombined state. We demonstrate that the critical stress required to achieve the recombined state is independent of the shear modulus. Rather the critical recombination stress depends on an energy difference between an unstable fault energy (γτ) and the intrinsic stacking fault energy (γτ-γisf). We report recombination energies of ΔW = 0.168 eV/Å and ΔW = 0.084 eV/Å, respectively, for the Cu screw dislocation within isotropic and anisotropic media. Finally, we develop an analytic model which provides insight into our simulation results which compare favourably with other (similar) models.},
doi = {10.1080/14786435.2017.1328138},
journal = {Philosophical Magazine (2003, Print)},
number = 25,
volume = 97,
place = {United States},
year = {2017},
month = {5}
}