Influence of coherent twin boundaries on three-point bending of gold nanowires

Abstract

In the present work we elucidate the deformation mechanisms of twinned Au nanowires (NWs) under three-point bending by means of molecular dynamics simulations. We further investigate the effects of twin boundary orientation, NW diameter and twin boundary spacing on the mechanical properties and deformation behaviors of NWs. Our simulation results reveal that dislocation slip, twin boundary associated mechanisms and deformation twinning work in parallel in the heterogeneous localized plastic deformation of twinned Au NWs under bending. The dislocation–twin boundary interactions can be significantly altered by changing the twin boundary orientation as well as the bending direction. Furthermore, the NW diameter and twin boundary spacing strongly influence the competition between individual deformation mechanisms, which in turn leads to extrinsic and intrinsic size effects on the strength and the bending ductility of the NWs.