The stress dependence of a lock which consisted of an a/3[l00] stair-rod, symmetrically located between 2 Shockley partials in face-centred cubic Ni, was examined by means of atomistic simulation. The applied stress forced the partials into the stair rod. As the partials moved into the lock, with increasing strain, the separation distances were found to be reasonably consistent with a linear elastic calculation of the equilibrium separation; except at the closest approach, where the elastic calculations overestimated the separation. This over-estimation was attributed to core overlap. The lock underwent several unstable transitions before becoming an inverted form of its initial configuration. The sequence of transitions involved an asymmetrical configuration at 2.3% strain, which contained an extrinsic fault, a transition at 4.8% strain that changed the stair-rod to a/6[011], and a transition that inverted the lock at 6% strain; with the stair-rod becoming a/6[¯100]. The evolution of the lock was not reversible.

An Atomistic Study of the Strength of an Extended-Dislocation Barrier. M.I.Baskes, R.G.Hoagland, T.Tsuji: Modelling and Simulation in Materials Science and Engineering, 1998, 6[1], 9-18