Migration of nanosized liquid Pb inclusions attached to dislocations in Al was observed during in situ transmission electron microscopy heating experiments and monitored by real-time video recordings. The movements of the inclusions could be separated into two independent components parallel to and perpendicular to the dislocations respectively. Movements parallel to the dislocation lines display properties of partially confined one-dimensional random walks where smaller inclusions could be seen to move over distances that were many times their own sizes. In contrast, the trajectories perpendicular to the dislocation lines were within narrowly confined spaces. Frame-by-frame analysis of digitized video sequences recorded at different temperatures for the same inclusion attached to a nearly horizontal dislocation illustrates the 2 types of movement. The step lengths parallel to the dislocation increase rapidly with increasing temperature while the step lengths in the transverse movement only display a weak temperature dependence. A detailed statistical analysis of the inclusion trajectories documents that both patterns of movement were random. The activation enthalpy of the one-dimensional movement parallel to the dislocation was found to be 2.72eV at lower temperatures and 1.44eV at higher temperatures with a transition around 650-660K.

One-Dimensional Random Walk of Nanosized Liquid Pb Inclusions on Dislocations in Al. E.Johnson, M.T.Levinsen, S.Steenstrup, S.Prokofjev, V.Zhilin, U.Dahmen, T.Radetic: Philosophical Magazine, 2004, 84[25-26], 2663-73