Computer simulation of the dynamical and thermally activated motion of interstitial clusters in Fe

Using the computer simulation technique various properties of interstitial clusters (bundle of crowdions) in Fe has been investigated. The actual shapes of the hexagonal loops were studied in detail and it was found that the direction of each segment of a loop depends upon the loop size; that is, in smaller loops 〈1 1 1〉 direction is preferred and in larger loops 〈1 1 2〉 direction is realized, resulting in the higher Peierls stress for smaller loops and lower Peierls stress for larger loops. The behavior of the thermally activated motion of loops has been studied by the MD method, showing that the small loop I19 moved along 〈1 1 1〉 direction at 100 K under the aid of energy deposition 10 eV in a rather uniform way without clear kink formation.