It was recalled that the interpretation of Bordoni, and similar relaxation, phenomena in terms of the thermally activated stress-assisted formation of kink pairs on dislocation lines was well-established; assuming that the migration of kinks along dislocation lines was described by a high kink-mobility. On the other hand, this assumption was not valid if the activation enthalpy for kink migration was comparable to, or larger than, the formation enthalpy of kink pairs. This was true even if the activation enthalpy for kink migration was small when compared with the formation energy of kinks, but larger than the lowest thermal energies which were accessible in internal friction experiments. In such cases, not only migration but also annihilation and trapping of thermal kink pairs might produce internal friction peaks. Difference-differential equations, which governed thermal kink-pair evolution along dislocation lines under homogeneous applied shear stress, were derived and their time-dependent solutions were characterized in terms of relaxation times. From these solutions, it was possible to obtain the internal friction spectrum under experimental conditions.

Dislocation Relaxation Processes due to Kink Migration. E.B.Hermida, A.Seeger, W.Ulfert: Journal de Physique IV, 1996, 6[8], 175-8