Assessment of interatomic potentials for atomistic analysis of static and dynamic properties of screw dislocations in W

Cereceda, D. and Stukowski, Alexander and Gilbert, M.R. and Queyreau, Sylvain and Ventelon, Lisa and Marinica, Mihai-Cosmin and Perlado Martín, José Manuel and Marian, Jaime (2013). Assessment of interatomic potentials for atomistic analysis of static and dynamic properties of screw dislocations in W. "Journal of Physics: Condensed Matter", v. 25 (n. 8); pp.. ISSN 0953-8984. https://doi.org/10.1088/0953-8984/25/8/085702.

Description

Title: Assessment of interatomic potentials for atomistic analysis of static and dynamic properties of screw dislocations in W
Author/s:
  • Cereceda, D.
  • Stukowski, Alexander
  • Gilbert, M.R.
  • Queyreau, Sylvain
  • Ventelon, Lisa
  • Marinica, Mihai-Cosmin
  • Perlado Martín, José Manuel
  • Marian, Jaime
Item Type: Article
Título de Revista/Publicación: Journal of Physics: Condensed Matter
Date: February 2013
ISSN: 0953-8984
Volume: 25
Subjects:
Faculty: Instituto de Fusión Nuclear (UPM)
Department: Otro
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Screw dislocations in bcc metals display non-planar cores at zero temperature which result in high lattice friction and thermally-activated strain rate behavior. In bcc W, electronic structure molecular statics calculations reveal a compact, non-degenerate core with an associated Peierls stress between 1.7 and 2.8 GPa. However, a full picture of the dynamic behavior of dislocations can only be gained by using more efficient atomistic simulations based on semiempirical interatomic potentials. In this paper we assess the suitability of five different potentials in terms of static properties relevant to screw dislocations in pure W. Moreover, we perform molecular dynamics simulations of stress-assisted glide using all five potentials to study the dynamic behavior of screw dislocations under shear stress. Dislocations are seen to display thermally-activated motion in most of the applied stress range, with a gradual transition to a viscous damping regime at high stresses. We find that one potential predicts a core transformation from compact to dissociated at finite temperature that affects the energetics of kink-pair production and impacts the mechanism of motion. We conclude that a modified embedded-atom potential achieves the best compromise in terms of static and dynamic screw dislocation properties, although at an expense of about ten-fold compared to central potentials.

More information

Item ID: 25682
DC Identifier: http://oa.upm.es/25682/
OAI Identifier: oai:oa.upm.es:25682
DOI: 10.1088/0953-8984/25/8/085702
Official URL: http://iopscience.iop.org/0953-8984/25/8/085702
Deposited by: Memoria Investigacion
Deposited on: 18 Apr 2015 07:48
Last Modified: 06 Sep 2017 15:31
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