Grain boundary segregation: equilibrium and non-equilibrium conditions

The segregation of Bi to Cu grain boundaries can be characterized as either equilibrium or non-equilibrium segregation. The experimental conditions of the segregation process determine the type of segregation behavior that is achieved. Classical McLean equilibrium segregation can be achieved through Bi grain boundary segregation from a constant vapor source with long anneal times. The Chang dislocation-pipe diffusion model of Bi segregation more accurately describes the onset of Bi segregation from an instantaneous source for short anneal times. A discussion on the conditions defining Bi segregation behavior is presented. (C) 2002 Acta Materialia, Inc. Published by Elsevier Science Ltd. All rights reserved