Regensburg 2019 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 12: Poster session I
MM 12.14: Poster
Montag, 1. April 2019, 19:15–20:45, Poster C
Atomistic Simulation of Incipient Plasticity in Compressed Au Nanowires — •Aviral Vaid1, Subin Lee2, Julien Guenole1, Arun Prakash1, Sang Ho Oh2, and Erik Bitzek1 — 1Materials Science and Engineering, Institute I, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany — 2Department of Energy Science, Sungkyunkwan University (SKKU), Suwon, Republic of Korea
Modern in-situ TEM experiments offer a unique possibility of imaging the nucleation of dislocations and the resulting plasticity in metallic nanowires. But the time resolution of these experiments is often too limited to study the details of dislocation-based deformation processes. Here, we present our results on recent atomistic simulations addressing the mechanisms and conditions under which prismatic dislocation loops can form during uniaxial compression tests of [110] oriented Au nanowires as reported by Lee et. al (Nat. Comm., 2014, 5, 3033). Such dislocations with Burgers vector parallel to the compression axis were unexpected, as they experience no resolved shear stress during uniaxial compression. Molecular dynamics simulations using an EAM potential and different indenter types and radii as well as nanowire geometries and sizes allowed to reproduce the observed prismatic dislocation loops and identify their formation mechanism. Building a model based on the geometry of the nanowire cap and the indenter radius, we derived a criterion under which conditions prismatic loops could form. Furthermore, we deduced the size range of asperities on the nominally flat punch indenter necessary for the formation the prismatic dislocation loops observed in experiments.