Abstract
In order to clarify the shear instability condition of local field, which induces a dislocation nucleation, 10 times of molecular dynamics simulations in a tension of nickel nano-wire (cross section: 30a×30a) were carried out. The results obtained are summarized as follows. (1) The partial dislocation nucleated from the edge of wire at εzz=0.093-0.096 (2) Dislocation nucleation site was different in each simulation due to the statistical fluctuation. (3) The strain concentration was observed in a 1/4 sphere of 3.0nm radius from the nucleation site before the dislocation appeared. (4) Detail observation revealed that the dislocation nucleated when the strain distribution in the region exceeded a criterion (critical curve). (5) The local strain concentration disappeared by the fluctuation when the strain distribution was lower than the critical curve. (6) The strain distribution on the critical curve brought about the dislocation nucleation when the rate of number of unstable lattices was higher than 0.1s-1.
