On the structure and energy of dissociated dislocations in F.C.C. metals

Abstract

Atomic-scale computer simulations using many-body interatomic potentials have been carried out to investigate the energy changes and equilibrium configurations associated with the dissociation of perfect and Lomer dislocations in copper and silver. The state of minimum energy is close in both cases to that given by the use of linear elasticity theory, and the Lomer dislocation adopts the asymmetric Lomer-Cottrell arrangement predicted by the same approach. The absolute energy values obtained from elasticity for the equilibrium dissociated configurations agree well with those found by computer simulation, but the elastic model does not accurately describe the energy changes associated with dissociation of the Lomer dislocation, thus confirming the conclusions drawn recently by Saada and Douin.