Extended dislocation lozenges and dipoles in f.c.c. crystals

Abstract

In addition to the standard extended dislocation dipoles, we show that there are four additional stable defects with lozenge-shaped cross-sections. The relative stability of these various types of extended dipoles and faults in silver, a typical f.c.c. metal, is numerically evaluated. Isotropic linear elasticity is assumed in the analysis. The equilibrium configurations and the interaction energy of the unreacted, extended dislocation pairs gliding on parallel {111} planes are calculated. The change in energy is then computed after the extended dislocations near their equilibrium positions dissociate and react to form the faulted configurations. The results predict stable lozenge arrays for reactant screw dislocations in addition to the traditional dipoles predicted for 60[ddot] reactant mixed dislocations.