Model steel and Ni-(2 to 10)at%Si alloys were irradiated in order to investigate mechanisms of radiation-induced grain boundary migration. An initial incubation stage, and 3 migration stages, were observed. The incubation period depended upon the irradiation temperature and the solute concentration. Activation energies were estimated from the temperature-dependence of the boundary migration velocity during the first stage and the incubation response. The activation energies for each alloy were lower than that for boundary migration during thermal annealing. It was suggested that the grain-boundary migration under irradiation was caused by enhanced boundary diffusion and the preferential rearrangement of undersized interstitial solute atoms which diffused, via a mixed dumb-bell mechanism, towards the grain boundary.

Effects of Interaction between Point Defects and Solutes on Grain Boundary Segregation and Migration. H.Kanda, H.Takahashi, N.Hashimoto, N.Sakaguchi: Materials Science Forum, 1999, 294-296, 157-60