Dislocation dynamics simulations of the Bauschinger effect in metallic thin films

TitleDislocation dynamics simulations of the Bauschinger effect in metallic thin films
Publication TypeJournal Article
Year of Publication2012
AuthorsZhou CZ, LeSar R
Journal TitleComputational Materials Science
Volume54
Pages350-355
Date Published03
Type of ArticleArticle
ISBN Number0927-0256
Accession NumberWOS:000300471500051
Keywordsaluminum, Bauschinger effect, copper-silica, dislocation dynamics, FCC METALS, Grain boundaries, Passivation layer, PLASTIC-DEFORMATION, relaxation, single-crystals, size, slip, thin films, transmission
Abstract

Three-dimensional dislocation dynamics simulations were used to examine the role of surface passivation on the plasticity of thin films. A simple line-tension model was used to model the dislocation transmission cross grain boundaries. We find that passivated thin films have a higher hardening rate and strength than freestanding films and that the hardening rate increases with decreasing film thickness. Under unloading, passivated films exhibit a significant Bauschinger effect in which reverse plastic flow occurs during unloading. The Bauschinger effect is enhanced by an increasing pre-strain or by decreasing the aspect ratio of the film. The reverse motion of dislocation pile-ups and the collapse of misfit dislocations were found to be responsible for the observed Bauschinger effect in passivated films. The predicted deformation behavior is in excellent agreement with that seen experimentally. Published by Elsevier B.V.

URL<Go to ISI>://WOS:000300471500051
DOI10.1016/j.commatsci.2011.09.031
Alternate JournalComput. Mater. Sci.