A universal plastic deformation mechanism for metallic glass

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Abstract

It is commonly believed that shear banding in metallic glasses originates from individual stress concentrators having quadrupolar symmetry. In this contribution we show experimental evidence of a characteristic signature present in shear bands manifested in the form of sinusoidal density variations elucidating the underlying mechanisms of shear band formation. 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. It crucially provides the non-trivial connections between the different magnitudes for dilated and densified regions, on 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, resulting from the alignment of Eshelby-like quadrupoles, are fundamental for the plastic deformation of all metallic glasses, and, possibly, for all amorphous materials in general [1].

Speakers from the University of Münster

Rösner, Harald

Professorship of Materials Physics (Prof. Wilde)