A recent interatomic potential for alpha-zirconium was used to investigate the atomic configuration and motion of point defect clusters. The structure of the single self-interstitial atom exerted a strong influence on the properties of small clusters containing up to six interstitials. For a given number of defects in this size range, several configurations exist with similar formation energy but different dynamic properties, i.e. they may be sessile or glissile. The movement of small clusters was three-dimensional and involves combinations of the different configurations. As cluster size increases, the influence of the configuration of the stable single self-interstitial atom vanishes and the interstitials orientate to achieve near-perfect crystal structure inside the cluster and a dislocation-core arrangement at the periphery. Movement of clusters larger than 12 self-interstitial atoms was one-dimensional along the direction of the Burgers vector. The stable configurations of vacancy clusters were also studied. The results were compared with those predicted with a model based on an earlier interatomic potential.

On the Structure and Mobility of Point Defect Clusters in Alpha-Zirconium: a Comparison for Two Interatomic Potential Models. N.de Diego, A.Serra, D.J.Bacon, Y.N.Osetsky: Modelling and Simulation in Materials Science and Engineering, 2011, 19[3], 035003