A universal deformation mechanism for metallic glasses

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Abstract

In this contribution we show evidence that shear banding in metallic glasses originates from individual stress concentrators having quadrupolar symmetry. Microstructural investigations using transmission electron microscopy revealed a characteristic signature present in shear bands manifested in the form of sinusoidal density variations. We present an analytical solution for the observed post-deformation state derived from continuum mechanics using an alignment of quadrupolar stress field perturbations for the plastic events. This crucially provides the non-trivial connections between the different magnitudes for dilated and densified regions, on the one hand, and the bulk modulus and sample’s density, on the other. Since qualitatively similar features were observed for different types of metallic glasses having different compositions and vastly different characteristics, the conclusion is drawn that periodic density variations in shear bands are a fundamental feature for the plastic deformation of all metallic glasses, and, possibly, for all amorphous materials in general.

Speakers from the University of Münster

Rösner, Harald

Professorship of Materials Physics (Prof. Wilde)