Non-repeatability of large plasticity for Fe-based bulk metallic glasses

Serrated flow is an essential characteristic of the plastic deformation of metallic glasses. Under restricted loading conditions, the formation and expansion of shear bands act as the serrated flow of stress-strain curves in metallic glasses. In this work, serrated flows in Fe50Ni30P13C7 glassy samples with different plasticity were studied. The distribution histogram shows a monotonically decreasing trend during the initial deformation stage (i.e., the plastic deformation in the range of 0e8%), whereas in the following deformation stage (i.e., a plastic deformation of 8e14%), the stress drop frequency distribution presents both a monotonically decreasing distribution and a peak shape similar to chaotic dynamics. It is shown that the spatial evolution behavior of shear bands in Fe50Ni30P13C7 metallic glasses evolved from self-organized critical to chaotic dynamics in the form of serrated flow, which reveals the origin of discrete plasticity of Fe-based bulk metallic glasses. This study has potential applications for understanding the plastic deformation mechanism. (C) 2016 Elsevier B.V. All rights reserved.