The thermally activated transport of highly mobile dislocation loops was considered in terms of a line tension model in which the dislocation loops were assumed to be flexible strings. The activation energy and transition rate were calculated on the basis of classical rate theory. The activation energy merely increased with the length of the dislocation loops. However, the activation process and temperature dependence of the transition rate changed qualitatively at a critical length, Lc. If the dislocation loops were longer than the critical length, thermal activation occurred via conventional double-kink formation on the dislocation lines. On the other hand, if the dislocation loops were shorter than Lc, the saddle-point configuration was not the double-kink type but a non-deformation one.

Analysis of the Thermal Activation of High-Mobility Dislocation Loops. K.Ohsawa, E.Kuramoto: Materials Transactions, 2005, 46[3], 457-62