By using computer simulation techniques, various properties of interstitial clusters (bundle of crowdions) were investigated. The shapes of the hexagonal loops were studied in detail and it was found that the direction of each segment of a loop depended upon the loop size. That is, in smaller loops the <111> direction was preferred and, in larger loops, the <112> direction was found; resulting in a higher Peierls stress for smaller loops and a lower Peierls stress for larger loops. The behavior of the thermally activated motion of loops was studied by using the molecular dynamics methods; thus showing that the small loop, I19, moved along the <111> direction at 100K, under an energy deposition of 10eV; in a rather uniform way without clear kink formation.

Computer Simulation of the Dynamic and Thermally Activated Motion of Interstitial Clusters in Fe. E.Kuramoto, K.Ohsawa, J.Imai, K.Obata, T.Tsutsumi: Journal of Nuclear Materials, 2004, 329-333[2], 1223-7