Nonplanar core and dynamical behavior of screw dislocations in copper at high velocities

D. Mordehai, I. Kelson, and G. Makov
Phys. Rev. B 74, 184115 – Published 27 November 2006

Abstract

The structure of high-velocity screw dislocations in Cu was investigated using molecular dynamics. We observed that the dissociation width of the dislocation into its partials is velocity dependent and identified two main regimes at low and high velocities with respect to the shear wave velocity. In the first regime the drag coefficient of the dislocation is temperature dependent and the dissociation width decreases with the velocity. In the second regime the drag coefficient is an order of magnitude higher than in the first regime and is temperature independent. In this regime the trailing partial spreads from the slip plane onto the cross-slip plane and the dislocation core becomes nonplanar. Due to this nonplanar structure, the dislocation widens as the velocity increases and the partial separation becomes unstable at velocities above 0.67 times the shear wave velocity. We derive an elastic-continuum model for the gliding dislocation structure.

    • Received 28 December 2005

    DOI:https://doi.org/10.1103/PhysRevB.74.184115

    ©2006 American Physical Society

    Authors & Affiliations

    D. Mordehai* and I. Kelson

    • School of Physics and Astronomy, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel

    G. Makov

    • Department of Physics, NRCN, PO. Box 9001, Beer Sheva, Israel

    • *Present address: Service de Recherches de Métallurgie Physique, CEA/Saclay, 91191 Gif-sur-Yvette, France.

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    Issue

    Vol. 74, Iss. 18 — 1 November 2006

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