Dislocation Dynamics Simulations of Plasticity in Polycrystalline Thin Films
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. Zhou and R. A. LeSar, "Dislocation Dynamics Simulations of Plasticity in Polycrystalline Thin Films," International Journal of Plasticity, vol. 30-31, pp. 185-201, Elsevier Limited, Mar 2012.
The definitive version is available at http://dx.doi.org/10.1016/j.ijplas.2011.10.001
Materials Science and Engineering
Keywords and Phrases
Grain Boundary; Size Effect; Spiral Source; Thin Films; Discrete Dislocation Dynamics; Dislocation Densities; Dislocation Dynamics Simulation; Grain Diameter; Grain Size; Polycrystalline Thin Film; Power Law; Size Effect; Spiral Sources; Statistical Variations; Stress Scale
International Standard Serial Number (ISSN)
Article - Journal
© 2012 Elsevier Limited, All rights reserved.