Viscoelasticity from a microscopic model of dislocation dynamics

M. Christina Marchetti, Syracuse University
Karl Saunders, Syracuse University

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Copyright © 2002 American Physical Society. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Physical Society. The following article appeared in Physical Review B and may be found at http://dx.doi.org/10.1103/PhysRevB.66.224113.

NOTE: At the time of publication, the author Karl Saunders was not yet affiliated with Cal Poly.

Abstract

It is shown that the dynamics of a viscoelastic medium can be modeled as that of a two-dimensional crystal with a finite concentration of dislocations, as well as vacancy and interstitial defects. At the longest length scales the viscoelasticity is described by the simplest Maxwell model, whose shear and compressional relaxation times are obtained in terms of microscopic quantities, including the density of free dislocations. At short length scales, t bond orientational order effects become important and lead to wave vector dependent corrections to the relaxation times.