Regensburg 2007 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 2: SYM Micro- and Nanomechanics I
MM 2.5: Vortrag
Montag, 26. März 2007, 12:00–12:15, H16
Investigation of the size dependent plasticity of micro-pillars by discrete dislocation dynamics — •Daniel Weygand1, Jochen Senger1, Oliver Kraft1,2, and Peter Gumbsch1,3 — 1IZBS, University of Karlsruhe, Karlsruhe, Germany — 2IMF II, Forschungszentrum Karlsruhe, Germany — 3IWM, Fraunhofer Institut, Freiburg, Germany
The understanding of the plasticity of sub-micrometer sized metallic components is of relevance due to the increasing use of small scale devices. The reliability of such structures is of importance for technical applications. As indicated by many experimental studies on sub-micron sized samples, crystalline materials in general display pronounced size effects regarding their mechanical behavior. In order to investigate the microstructural origin of the size effect the plastic flow of uniformly loaded pillars is modelled using a three dimensional discrete dislocation dynamics tool. Starting from Frank-Read sources of given length and random orientation, the simulated flow stress at 0.2% plastic strain shows a size effect, quite similar to experimental findings for larger strains. Furthermore the scattering in the simulated stress-strain curves decreases with increasing sample size, which reflects that plasticity of small scale samples is very sensitive to the underlying dislocation microstructure. Statistical properties of the resulting dislocation microstructure are discussed as well.