Dislocation dynamics simulations of plasticity in polycrystalline thin films

TitleDislocation dynamics simulations of plasticity in polycrystalline thin films
Publication TypeJournal Article
Year of Publication2012
AuthorsZhou CZ, LeSar R
Journal TitleInternational Journal of Plasticity
Volume30-31
Pages185-201
Date Published03
Type of ArticleArticle
ISBN Number0749-6419
Accession NumberWOS:000301626400009
Keywordsau films, copper-films, dislocation dynamics, grain boundary, grain-boundary interactions, high-rate deformation, metal-films, nanocrystalline aluminum, Size effect, slip, source, Spiral, strained-layer, thin films, transfer mechanisms, TRANSMISSION ELECTRON-MICROSCOPE, yield strength
Abstract

3-D discrete dislocation dynamics simulations were used to investigate the size-dependent plasticity in polycrystalline, free-standing, thin films. A simple line-tension model was used to model the dislocation transmission cross grain boundaries. At a constant film thickness, the total dislocation density and the strength increase as grain size decreases. The yield stress scales with grain diameter with a power law, with an exponent that varies with both film thickness and grain size for thicker films. In addition, the yield strength of films scales proportionally to the reciprocal of thickness and matches experiment results well. A spiral source model was developed that relates the strength of films to the statistical variation of the spiral source length, and accurately predicts the size-dependent strength in polycrystalline thin films. (C) 2011 Elsevier Ltd. All rights reserved.

URL<Go to ISI>://WOS:000301626400009
DOI10.1016/j.ijplas.2011.10.001
Alternate JournalInt. J. Plast.