Fig. 2: Dislocation nucleation assisted by surface diffusion in an Ag NW.
From: Atomistic processes of surface-diffusion-induced abnormal softening in nanoscale metallic crystals
a, TEM image of a pristine 6.6-nm-diameter Ag NW under < 112 > tensile loading at room temperature and a strain rate of ~ 10−3 s−1. b–f, Sequential TEM images showing the lateral migration of three atomic steps (surface atom diffusion) on the {111} surface of the Ag NW. The initial position of step 2 was marked by a navy blue circle. g, A partial dislocation activity observed at the overlapping position of steps 2 and 3. h, A one-layer surface step (step 4) formed by the elimination of a stacking fault. i-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 specific color. m, Lattice stress versus applied strain curve during tensile loading; points (a–l) indicate the states of deformation shown in the TEM images of a–l. The error bars represent the variations of the measured lattice stresses at different locations of the nanowire.
