Computer simulation of atomic properties and dynamic behavior of interstitial clusters in Ni

The atomic structure and dynamic behavior of interstitial clusters, i.e., a bundle of 〈110〉 crowdions, have been investigated in a model Ni lattice. An extended dislocation loop was obtained after full relaxation of a loop of hexagonal shape, consisting of four dislocation segments lying on {111} slip planes and two dislocation segments on {100} slip planes. The dislocation segments on {111} slip planes are extended, but the segments on {100} slip planes are not extended. By observing the motion of a dislocation loop under axially symmetrical shear stress, the Peierls stress for the dislocation loop was obtained. Also, a diamond-shaped dislocation loop was constructed in the model lattice, consisting of four dislocation segments on {111} slip planes and no segments on {100} slip planes. The Peierls stress for this diamond-shaped dislocation loop was found to be less than that for the hexagonal-shaped dislocation loop.