ATOMIC-STRUCTURE AND ENERGETICS OF CONSTRICTED SCREW DISLOCATIONS IN COPPER

Atomistic simulations of cross slip of a dissociated screw dislocation have been performed. Shapes and energetics of different dislocation c onfigurations relevant to cross slip in an f.c.c. metal (Cu) are deter mined. The minimum stress-free activation energy and activation length in the Friedel-Escaig cross-slip mechanism are determined. The simula tions reveal a new energetically favourable configuration of a dissoci ated screw dislocation not previously considered. The importance of th is configuration to surface nucleated cross slip is discussed. (C) 199 7 Elsevier Science S.A.