Plastic deformation of freestanding thin films: Experiments and modeling

L. Nicola, Y. Xiang, J.J. Vlassak, E. van der Giessen, A. Needleman

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192 Citaten (Scopus)
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Samenvatting

Experimental measurements and computational results for the evolution of plastic deformation in freestanding thin films are compared. In the experiments, the stress-strain response of two sets of Cu films is determined in the plane-strain bulge test. One set of samples consists of electroplated Cu films, while the other set is sputter-deposited. Unpassivated films, films passivated on one side and films passivated on both sides are considered. The calculations are carried out within a two-dimensional plane strain framework with the dislocations modeled as line singularities in an isotropic elastic solid. The film is modeled by a unit cell consisting of eight grains, each of which has three slip systems. The film is initially free of dislocations which then nucleate from a specified distribution of Frank-Read sources. The grain boundaries and any film-passivation layer interfaces are taken to be impenetrable to dislocations. Both the experiments and the computations show: (i) a flow strength for the passivated films that is greater than for the unpassivated films and (ii) hysteresis and a Bauschinger effect that increases with increasing pre-strain for passivated films, while for unpassivated films hysteresis and a Bauschinger effect are small or absent. Furthermore, the experimental measurements and computational results for the 0.2% offset yield strength stress, and the evolution of hysteresis and of the Bauschinger effect are in good quantitative agreement. (c) 2006 Elsevier Ltd. All rights reserved.

Originele taal-2English
Pagina's (van-tot)2089-2110
Aantal pagina's22
TijdschriftJournal of the Mechanics and Physics of Solids
Volume54
Nummer van het tijdschrift10
DOI's
StatusPublished - okt.-2006

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