The kinetics of Bi segregation at grain boundaries in polycrystalline samples which contained 25 or 50ppm[at]Bi was investigated at various temperatures. Within the 2-phase region of the Cu-Bi phase diagram, the kinetics of Bi segregation could be described by a model which involved enhanced diffusion along dislocations. Within the single-phase region, it obeyed the McLean model. The enhanced pipe diffusion was explained in terms of the precipitation of a Bi-rich liquid phase along dislocations in the 2-phase region. This dislocation-pipe model yielded a linear relationship between Bi segregation and annealing time.

Kinetics of the Bi Segregation at Grain Boundaries in Polycrystalline Cu. L.S.Chang, E.Rabkin, B.B.Straumal, B.Baretzky, W.Gust: Materials Science Forum, 1999, 294-296, 585-8