Suppressing instabilities in defect-scarce nanowires by controlling the energy release rate during incipient plasticity

Abstract

Stabilizing deformation within defect-scarce nanowires, which feature dislocation nucleation-mediated strengths, is experimentally challenging due to the high elastic strain energy that dissipates at ultrahigh rates at the onset of plastic deformation. Here, frame stiffness-enhanced in situ tensile tests were perform on defect-scarce nanowires, where the tensile deformation response of the nanowires is measured by local strain analyses. The influence of frame stiffness on incipient plasticity is evaluated by an energy criterion that considers the energy release rate during the incipient plastic event, which gives rise to a condition for stable plasticity. Without altering the underlying deformation mechanism, the presented results demonstrate that the ductility of defect-scarce nanowires can be substantially extended. As a consequence, the full evolution of plastic deformation within defect-scarce nanowires is captured, which include observations of local yield events and the propagation of plasticized zones. Keywords: Nanowire, Nanomechanical testing, Nanostructure engineering, Pd nanowire