Nanosized solid Pb inclusions in Al have a face-centered cubic structure and perfect cubo-octahedral shape. When the inclusions melted they attained a rounded equilibrium shape and ,due to the low miscibility between the two elements, the liquid inclusions were retained as individual nanosized droplets located inside the solid Al matrix. As the temperature was increased the smaller liquid Pb inclusions were observed to move in a 3-dimensional random walk over distances that could be orders of magnitude larger than their size. Inclusions attached to dislocations exhibited a similar type of random walk confined to long-distance one-dimensional movement along the dislocation lines and short-range 2-dimensional vibrations perpendicular to the dislocation lines. The diffusion coefficients of the moving inclusions could be obtained from an Einstein-Smoluchowski analysis of the inclusion traces providing input for information on the mechanisms responsible for the movements.

Brownian Motion of Liquid Lead Inclusions along Dislocations in Aluminium. E.Johnson, S.Steenstrup, M.Levinsen, V.Prokofjev, V.Zhilin, U.Dahmen: Journal of Materials Science, 2005, 40[12], 3115-9