Fractal nature of multiple shear bands in severely deformed metallic glass

Abstract

We present an analysis of fractal geometry of extensive and complex shear band patterns in a severely deformed metallic glass. We show that the shear band patterns have fractal characteristics, and the fractal dimensions are determined by the stress noise induced by the interaction between shear bands. A theoretical model of the spatial evolution of multiple shear bands is proposed in which the collective shear bands slide is considered as a stochastic process far from thermodynamic equilibrium.

Intrinsic versus extrinsic effects on serrated flow of bulk metallic glasses

“…This is consistent with the recent studies on the serrated flow dynamics where the single shear band has a chaotic dynamics with a Gaussian-like peak distribution of serrations [36,42]. In contrast, the serrated flow of ductile BMGs with multiple shear bands tends to have a dynamic state of self-organized criticality (SOC) with a power-law or scalefree distribution of serrated events [36,38,43]. Similar behavior can be also found in the distribution of t L and t W .…”

The fracture of bulk metallic glasses

“…In addition, these sliding events appeared in an intermittent, trigger aftershock pattern in which small events leading to smoothing in a larger scale and a larger event later on, similar to what happened in the fault dynamics [115]. Furthermore, fractal analysis on surface morphology at compressive plastic strains in BMGs indicates that multiple shear band patterns are self-similar fractals [116]. The formation and interactions of multiple shear bands during deformation of ductile BMGs could be a laboratory system to mimic the earthquakes [112].…”

Avalanche localization and crossover scaling in amorphous plasticity

“…At the same time, experiments [11][12][13][14][15] and molecular dynamics simulations [16][17][18][19][20][21][22] show that scale-free avalanches and complex strain patterns are also shared by amorphous materials where localized defects are not present. An open question that remains is whether the universality class of amorphous plasticity is the same as that of crystalline plasticity.…”