Size-dependent yield stress in twinned gold nanowires mediated by site-specific surface dislocation emission

Large-scale molecular dynamics simulations were performed to demonstrate the synergistic effects of twin boundaries and free surfaces on dislocation emission in gold nanowires under tensile loading. It is revealed that the addition of nanoscale twins to crystalline nanowires can act to either increase or decrease their resistance to slip in tension, depending on both sample diameter and number of twins per unit length. Site-specific surface dislocation emission and image forces due to twin boundaries are used to explain the size-dependence of yield stress in twinned gold nanowires. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3222936]