Roots seeking of multiple shear-bands in amorphous alloys at the atomic scale

Abstract

The propagation of shear-bands is of utmost importance in understanding the macro and microscopic deformations of bulk metallic glasses (BMGs). In this study, using molecular dynamics simulations to elucidate the intricate atomic-scale mechanisms governing dynamic continuum shear-bands and microstructural evolution during deformation. This work provides compelling evidence of self-organized critical behavior, as evidenced by the observation of serrated flow patterns and distributions of elastic energy density. Moreover, we unveil the influence of notch length on the principal shear-band based on the steep stress drop (i.e., Δτ =τy-τs, distinct from serrated flows), strength-normalized difference (i.e., Δτ/τy), and probability distribution of shear-strain. The effective blocking of shear bands by nanocrystal second phase can be attributed to the synergistic reinforcement effect of dislocations and nano-stacking faults. Finally, the analysis of the serrated flow behavior and stress-increment distribution during nanoindentation establishes the connection between micromechanical behavior, shear-band evolution, and macroscopic mechanical properties.