Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 33: Topical Session Theory meets Experiment II - Nanocomposites and Microstructure
MM 33.4: Vortrag
Mittwoch, 28. März 2012, 12:30–12:45, TC 006
Properties of fivefold twinned nanowires derived from microstructural constraints and anisotropic elasticity — •Florian Niekiel1, Erdmann Spiecker1, and Erik Bitzek2 — 1Center for Nanoanalysis and Electron Microscopy (CENEM), Friedrich-Alexander-Universität Erlangen-Nürnberg — 2Institute I: General Materials Properties, Department of Material Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg
Fivefold twinned metallic nanowires of fcc crystal structure have lately attracted a lot of attention because of their interesting properties and potential applications. Such nanowires consist of five segments, which are joined by {111}-twin boundaries, sharing a common crystal direction along the wire axis. The angular misfit of 7.35° resulting from joining the five wedge shaped segments necessitates the existence of a positive partial wedge disclination at the quintuple line present in the center of the nanowire. This peculiar microstructural constraint gives rise to significantly different properties of fivefold twinned nanowires in comparison to their single crystalline counterparts.
Here atomistic simulations and experimental diffraction measurements are combined to study the stress and strain state in fivefold twinned nanowires. Based on the findings a theoretical framework accounting for anisotropic elasticity is developed to quantitatively predict the mechanical properties of such nanowires as function of the used material. In this way the model helps not only to understand the properties of fivefold twinned structures but also to design their properties for future applications.