CUED Publications database

The injection of a screw dislocation into a crystal: Atomistics vs. continuum elastodynamics

Verschueren, J and Gurrutxaga-Lerma, B and Balint, DS and Dini, D and Sutton, AP (2017) The injection of a screw dislocation into a crystal: Atomistics vs. continuum elastodynamics. Journal of the Mechanics and Physics of Solids, 98. pp. 366-389. ISSN 0022-5096

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The injection (creation) process of a straight screw dislocation is compared atomistically with elastodynamic continuum theory. A method for injecting quiescent screw dislocations into a crystal of tungsten is simulated using non-equilibrium molecular dynamics. The resulting stress fields are compared to the those of elastodynamic solutions for the injection of a quiescent screw dislocation. A number of differences are found: a plane wave emission is observed to emanate from the whole surface of the cut used to create the dislocation, affecting the displacement field along the dislocation line (z), and introducing displacement field components perpendicular to the line (along x and y). It is argued that, in part, this emission is the result of the finite time required to inject the dislocation, whereby the atoms in the cut surface must temporarily be displaced to unstable positions in order to produce the required slip. By modelling this process in the continuum it is shown that the displacements components normal to the dislocation line arise from transient displacements of atoms in the cut surface parallel to x and y. It is shown that once these displacements are included in the elastodynamic continuum formulation the plane wave emission in u is correctly captured. A detailed comparison between the atomistic and continuum models is then offered, showing that the main atomistic features can also be captured in the continuum. z

Item Type: Article
Divisions: Div C > Materials Engineering
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:34
Last Modified: 13 Apr 2021 08:15
DOI: 10.1016/j.jmps.2016.10.004