Defect clusters in Zn: A computer simulation study

Calculations on point-defect clusters in Zn are performed using a static simulation technique in conjunction with a many-body potential. The results are compared with the available experimental observations, theoretical estimates and previous computations in hcp metals with c/a ratios below the ideal value. Both monovacancy and divacancy defects demonstrate an anisotropic migration with almost the same activation energy, corresponding to that observed in recovery stage IV. Small vacancy clusters are found to favour three-dimensional agglomerates. Stability conditions for vacancy clusters to nucleate or break up (recovery stage V) are discussed. Small clusters of interstitials are shown to grow on the basal plane in forms based on the octahedral point defect, although the most stable single interstitial is the non-basal crowdion. Large single- and double-layer interstitial clusters are assigned to embryos of the experimentally observed dislocation loops.