Regensburg 2016 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 6: Liquid and Amorphous Metals II: Shear bands

MM 6.1: Talk

Monday, March 7, 2016, 11:30–11:45, H52

Nucleation and propagation of shear bands in metallic and network-forming glasses — •Richard Jana and Lars Pastewka — Institut für Angewandte Materialien - Computational Materials Science, Karlsruher Institut für Technologie (KIT), Karlsruhe, Deutschland

Molecular Dynamics simulations (MD) were used to study nucleation and propagation of shear bands during simple shear deformation of CuZr binary bulk metallic glasses (BMG), amorphous silicon (a-Si) and amorphous carbon (a-C). We find that the initial shear bands in a-Si and a-C are more localized than those found in CuZr. Shear bands in a-Si and a-C can be easily morphologically distinguished from their bulk from simple parameters such as the local coordination number and density. While such a clear signature of shear-banding is not found in local topological parameters for CuZr, such as short-range order (SRO) determined by Voronoi tessellation, we show by repeated deformation and quench sequences that in neither case dynamic shear localization through viscous heating and subsequent local softening is the cause of the localization. Nevertheless, thermal effects show impact on the shear localization, as shear bands vanish at elevated temperatures even below Tg. We correlate the temperature-dependence of coordination number and SRO with with the evolution of shear banding at elevated temperatures.