Fig. 5: Surface atom diffusion induced abnormal softening during plastic flow in an Ag NW.
From: Atomistic processes of surface-diffusion-induced abnormal softening in nanoscale metallic crystals
a Pristine Ag NW with a diameter of 13.1 nm as viewed along \([\bar{1}10]\) and loaded along \([\bar{1}\bar{1}2]\)-orientation at room temperature and a strain rate of ~ 10−3 s−1. b Two surface steps (steps 1 and 2) formed by full dislocation activities. c-h, Surface-diffusion-assisted migration of surface steps (steps 1 and 2) to the right side of the NW during tensile loading. i Two new surface steps (steps 3 and 4) in NW formed by full dislocation activities. j-l, Sequential TEM images showing the plastic flow of the Ag NW with a small number of surface diffusion. All scale bars are 2 nm. Each surface step is tracked by an arrow of a specific color. m Lattice stress versus applied strain curve during tensile loading corresponding to the sequence in a–l. The initial strains were nominalized by subtracting the plastic strain in the previous plastic deformation history. The error bars represent the variations of the measured lattice stresses at different locations of the nanowire.
