The results of molecular dynamics simulations of self-interstitial cluster diffusion in pure α-Fe and in a dilute Fe–1at%Cu alloy were reported for a number of cluster sizes, n ≤ 20. It was found that the effect of this oversized substitutional solute was to enhance the 3-dimensional character of small-cluster diffusion and to affect the general cluster diffusion properties. This was explained in terms of a mechanism which was based directly upon interactions between the atomic displacement field of the Cu atoms and the self-interstitial clusters. On the basis of the results, simple power laws were derived for the extrapolation of migration energies and diffusion pre-factors to larger sizes; as required for longer-range microstructural evolution models. It was considered that these laws represented an improvement over the parameterizations which had been used in previous calculations.

Dynamics of Self-Interstitial Cluster Migration in Pure α-Fe and Fe-Cu Alloys. J.Marian, B.D.Wirth, A.Caro, B.Sadigh, G.R.Odette, J.M.Perlado, T.Diaz de la Rubia: Physical Review B, 2002, 65[14], 144102 (11pp)