After giving an overview of the importance and present knowledge of diffusion along dislocations in materials, we present results of atomistic computer simulations of self-diffusion along a screw dislocation in Al. Using molecular dynamics simulations with an embedded-atom potential, we obtain dislocation diffusion coefficients in the presence of vacancies, self-interstitials, as well as without any point defects over a range of temperatures. Even in the absence of point defects, the dislocation core exhibits high diffusivity. The exact atomic mechanism of this intrinsic diffusion is not currently known but is likely related to thermal displacements of the dislocation line occurring by the formation and spreading of double-jogs. Equilibrium vacancies give a smaller contribution to the diffusion rate in comparison with the intrinsic mechanism, while the contribution of interstitials is negligible. The intrinsic mechanism of dislocation diffusion, if confirmed in other types of dislocations, may suggest a re-examination of our understanding of the role of point defects in dislocation mass transport.
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