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MM: Fachverband Metall- und Materialphysik

MM 31: Postersitzung II

MM 31.48: Poster

Mittwoch, 16. März 2011, 17:15–18:45, P5

In situ tensile testing of single crystal Au nanowires — Bahne Kapelle¹, •Burkhard Roos¹, Gunther Richter², and Cynthia A. Volkert¹ — ¹Institut für Materialphysik, Universität Göttingen — ²Max-Planck-Institut für Metallforschung, Stuttgart

The mechanical properties of nanoscale metals differ from those of macroscale samples, especially the increasing strength with decreasing sample size. In this work, the stress-strain behavior of single crystalline Au nanowires with diameters between 40 and 200 nm are studied using an instrumented tensile stage in an SEM. The wires are transferred from the growth substrate to the tensile stage without deforming them using a micromanipulator. Displacements are applied by a piezoelectric based actuator while forces are measured with a capacitive MEMS device. All tested wires show an initial elastic regime with a slope of around 68GPa, which is reversible on unloading. This is followed by a gradual onset of plasticity and eventually by fracture after a plastic strain of 1 to 3%. The failure stresses, which reach up to 1.2GPa, confirm the trend that smaller samples have higher flow stresses than bulk materials. Investigations of the failed wire segments, which were transferred subsequently to a TEM grid, confirm the size-dependent deformation mechanisms observed during in situ TEM tensile testing, namely that deformation proceeds by partial dislocation motion rather than full dislocation motion below a critical size of approximately 180 nm.