The dynamic behavior of small interstitial clusters (dislocation loops), including interaction with a self-interstitial atom and interaction between a self-interstitial atom and an edge dislocation, was studied by using molecular dynamics methods to clarify their role in the evolution of damage during irradiation. Of particular interest was the so-called production bias effect in 1-dimensional migration to sinks, and the so-called dislocation bias. A model crystal was constructed by using n-body potentials, and small interstitial clusters (such as a bundle of crowdions), a self-interstitial atom and an edge dislocation were inserted. It was found that the self-interstitial atom migrated to the edge-dislocation core and the final direction of the crowdion became parallel to the Burgers vector of the edge dislocation. The dynamic behavior of the loop, such as interaction with a crowdion on a central <11f> loop axis, was also investigated as a function of time. It was shown that a small initial cluster, such as I19, was very mobile during interaction with a crowdion. This showed that this interstitial cluster already possessed some characteristics of a dislocation loop of edge type, and the low Peierls potential for the motion of this loop was consistent with that of a straight edge dislocation.

MD Study of the Dynamic Behavior of Small Interstitial Clusters in Fe. M.Koyanagi, K.Ohsawa, E.Kuramoto: Journal of Nuclear Materials, 1999, 271-272, 205-8