Dresden 2014 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 18: Poster Session

MM 18.17: Poster

Montag, 31. März 2014, 18:00–20:00, P4

Effect of surfaces and interfaces on elastic properties of transition metals studied by DFT and EAM — •Tobias Klöffel¹, Erik Bitzek², and Bernd Meyer¹ — ¹Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, FAU Erlangen-Nürnberg — ²Department of Materials Science and Engineering, WW 1: General Materials Properties, FAU Erlangen-Nürnberg

Experimental studies show that defect-free metallic nanowires exhibit different elastic properties compared to their bulk counterparts. Atomistic calculations with embedded atom method (EAM) potentials show the same trend, however, at much smaller wire diameters. In addition, recent studies indicate that even nanowires with relative large diameter of about 200 nm to 1000 nm might posses a lower Young’s modulus, if they incorporate hundreds of twin boundaries (TBs) parallel to the wire axis.

We present first results of systematic atomistic calculations, searching for a possible source of this yet unknown effect, which could be responsible for a decreased Young’s modulus E. We first calculated E for a defect-free bulk cell and compared the results to a cell that included TBs parallel to the direction of the Young’s modulus using DFT. We also compared the interface-stress calculated by DFT and EAM to the surface-stresses, which are known to influence the elastic properties of materials. In a second step, we compared the elastic properties of model wires of different sizes with and without TBs using EAM potentials. First results will be discussed and compared to experimental findings.