Experimental observations of deformation behavior of bulk metallic glasses during wedge-like cylindrical indentation

This article reports on the in situ observations of deformation behavior of a metallic glass under a wedge-like cylindrical indenter. The experimental observations for various indenter radii provide information on both macroscopic and microscopic details of the deformation. The deformation zones developed under indenters with different radii that were found to be self-similar and in agreement with the predictions of continuum finite-element simulation with pressure-dependent yielding. There are two types of shear bands being identified beneath the indenter. A set of primary bands is identified as evolving with the process zone front and presents an included angle of 78–80°. The other set of bands evolves at a later stage of loading within the originally formed ones but with a consistently higher included angle of around 87°. Despite the richness of the shear-band details, the macroscopic trends, the force-indentation depth response, and the extent of deformation zones are well captured for this constrained deformation mode by the continuum models that address the onset of yielding only.