Molecular dynamics studies were made of the thermally activated motion of clusters of 3, 9 and 17 self-interstitial atoms in the α-phase at 90 to 1400K. The correlation between the motion of the center of mass of a cluster, and the individual jumps of its constituent atoms, was revealed. It was found that the self-interstitial atoms in a cluster jumped almost independently, and that their jump frequency depended upon the number of self-interstitial atoms in the cluster. This led to a simple relationship between the jump frequency of a cluster and the number of self-interstitial atoms which it contained. The reason for deviations of the cluster jump frequency from a simple Arrhenius relationship was considered. It was shown that such clusters executed an effectively random walk, giving a correlation factor of unity, only when the jump length which defined the diffusion was taken to be 3b or 4b; where b was the magnitude of the vector, ½<111>.

Mechanism of One-Dimensional Glide of Self-Interstitial Atom Clusters in α-Iron. A.V.Barashev, Y.N.Osetsky, D.J.Bacon: Philosophical Magazine A, 2001, 80[11], 2709-20