Shear band patterns in metallic glasses under static indentation, dynamic indentation, and scratch processes

The deformation structure in terms of shear band patterns in bulk metallic glasses (BMGs) under static indentation, dynamic indentation, and dynamic scratch tests has been investigated. The evolved shear band patterns appear to be a strong function of loading rate, although the plastic regions beneath the loading surface have similarities in shape irrespective of loading type. Comparison of currently available modeling estimates with experimental measurements has revealed that these models predict the plastic zone size reasonably well at low loads but deviate considerably at higher loads. The variation in spacing of shear bands is rationalized on the basis of the shear displacement accommodated by the shear bands formed under different loading rates, which results from a proposed shear-band formation mechanism based on the momentum diffusion model.