Five-fold twin and surface groove-induced abnormal size- and temperature-dependent yielding in Ag nanowires

Molecular dynamics simulations are used to investigate the influence of pre-existing five-fold twins and surface grooves on the yielding of Ag nanowires under uniaxial deformation. While a five-fold twin together with a surface groove generally lead to strengthening in Ag nanowires under tension, abnormal weakening effects are observed under compression at low temperatures when the nanowire diameter is increased. The peculiar size and temperature effects can be attributed to the toggling of dislocation nucleation between various preferential sites under different loading conditions.