Role of microscopic degrees of freedom in mechanical response of bicrystal nanopillars

This study investigated the high-strain rate deformation of bicrystal Cu nanopillars, using atomistic simulations. Nanopillars with minimum grain boundary energy were deformed to investigate the role of macroscopic degrees of freedom, finding that geometric parameters (Schmid factor) influence the stress–strain response. The deformation of metastable grain boundaries (GBs) revealed that in addition to geometric parameters, the response was also governed by the local atomic arrangement at the boundary, dictating the dislocation-GB interactions. These findings shed light on the response of nanopillars as a function of GBs and show the importance of both macroscopic and microscopic degrees of freedom on the mechanical response. GRAPHICAL ABSTRACT IMPACT STATEMENT Metastable states, an often ignored aspect of GB structure, is shown to have a strong influence on dislocation-GB interactions; shedding new light on mechanical response of realistic GBs.