Enabling ultrahigh plastic flow and work hardening in twinned gold nanowires

By using molecular dynamics simulations, we show that significant strain hardening and ultrahigh flow stresses are enabled in gold nanowires containing coherent (111) growth twins when balancing nanowire diameter and twin boundary spacing at the nanoscale. A fundamental transition in mechanical behavior occurs when the ratio of diameter to twin boundary spacing is larger than 2.14. A model based on site-specific dislocation nucleation and cross-slip mechanisms is proposed to explain the size dependence of flow behavior in twinned nanowires under tensile loading.