Spatial–Temporal evolution of shear banding in bulk metallic glasses

Abstract

Shear band behaviour plays a critical role in toughening and failure of bulk metallic glasses (BMGs). However, due to instability in time and inhomogeneity in space, spatial–temporal evolutions of shear bands are difficult to be studied in the past decades. Using digital image correlation (DIC) and infrared thermal imaging (ITI) technologies, uniaxial quasi-static compressions for Zr41.2Ti13.8Ni10Cu12.5Be22.5 BMG are carried out. The spatial–temporal evolutions of shear bands, as well as the relationship between shear band and failure in BMGs, are in-situ investigated. A theoretical evaluation of temperature is performed based on the heat conduction theory, in line with the experimental data. Moreover, a free volume theory-based amorphous viscoplasticity model is implemented by finite element method (FEM) to understand the shear band behaviour further. The nucleation, propagation, intersection of shear bands are investigated in detail, and the simulation results are in agreement with the experiments in some respects. Besides, it is found that the primary shear band tends to be activated more easily along a so-called dominant path generated after shear-band competitions. This paper provides insights for the prediction of the primary shear band, prevention of failure, and toughening method in BMGs.