The stability and mobility of self-interstitials and small interstitial clusters, In, in α-Fe was investigated by means of calculations performed in the framework of the density functional theory using the SIESTA code. The mono-, di- and tri-interstitials were shown to be made of (parallel) <110> dumb-bells and to migrate by nearest-neighbor translation–rotation jumps, according to Johnson’s mechanism. The <111> orientation of the dumbbells became energetically more favourable for I5 and larger clusters. The performance of a semi-empirical potential recently developed for Fe, including ab initio self-interstitial data in the fitted properties, was evaluated over the present results. The superiority over previous semi-empirical potentials was confirmed. Finally the impact of the present results on the formation mechanism of <100> loops, observed experimentally in α-Fe was discussed.

Stability and Mobility of Self-Interstitials and Small Interstitial Clusters in α-Iron - ab initio and Empirical Potential Calculations. F.Willaime, C.C.Fu, M.C.Marinica, J.D.Torre: Nuclear Instruments and Methods in Physics Research B, 2005, 228[1-4], 92-9