Dresden 2009 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 35: Poster Session II

MM 35.22: Poster

Wednesday, March 25, 2009, 16:30–18:30, P4

In-situ TEM and STM studies of dislocations in nano-scale metal samples — Burkhard Roos¹, •Sönke Schmidt¹, Daniel S. Gianola², Gunther Richter³, Astrid Pundt¹, and Cynthia A. Volkert¹ — ¹Institut für Materialphysik, Universität Göttingen — ²Insitut für Materialforschung II, Forschungszentrum Karlsruhe — ³Max-Planck-Institut für Metallforschung, Stuttgart

Metals at the nano-scale exhibit mechanical properties that are different from those at the macro-scale. The best known effect is the increase in strength with decreasing crystal size. However, present dislocation-based models fail to explain this effect. It is the goal of the studies described here to directly observe dislocations in small volumes in order to understand how they contribute to size dependent mechanical response. Two different experimental approaches are being taken. In the first approach, in-situ TEM is used to observe dislocation nucleation and storage during tensile testing of metal nano-wires. Initial results from ~100 nm diameter, single crystal Cu whiskers will be presented. In the second approach, in-situ STM will be used to observe the dislocation traces left at the surface of freshly deposited metal films. Results from deformed Cu films will be presented to show the feasibility of this method for providing quantitative information on dislocations during deformation.