Influence of microstructural features on the plastic deformation behavior of metallic nanoglasses

Abstract

We investigate the influence of microstructural properties on the plastic deformation behavior of Cu64 Zr36 nanoglasses by means of molecular dynamics simulations. Two different setups are used to prepare nanoglasses. One sample type is a nanoglass obtained by cold-compaction of chemically homogenous and inhomogenous nanoparticles. The second type is generated by assembling pre-shaped polyhedral cuts from the bulk phase. A detailed analysis of both types of microstructures shows that the volume fraction of interfaces in the particle-derived nanoglasses is significantly higher than in the bulk-derived nanoglasses with the same average grain size. The simulations also reveal a clearly distinct plastic response on uniaxial loading: The particle derived samples do not show a stress drop upon yielding, very little strain localization and no strain softening, whereas the bulk-derived samples exhibit a stress drop, strain softening and large strain localization upon loading. These findings are explained in terms of the different glass-glass interfaces present in both structure types. Our results therefore show that the macroscopic deformation behavior of metallic nanoglasses is intimately linked to the structure and topology of the glass-glass interfaces which in turn depend on the processing route.