Interactions between mobile dislocation loops in Cu and alpha-Fe

The relevance of one-dimensionally gliding clusters in the understanding of the damage accumulation produced by the displacement cascades has been underlined by the production bias model. The properties and mobility of isolated clusters of vacancies and self-interstitials have been recently studied by molecular dynamics and valuable information about their diffusional characteristics is obtained. The next step in the understanding of radiation damage should include the possible reactions of these clusters with other clusters, dislocations and other sinks. In this paper we present the first results of a molecular dynamics study of interactions between glissile interstitial clusters and small dislocation loops in alpha-Fe and Cu. Different types of interactions have been studied between clusters of different sizes (from 12 to 91 defects) in the temperature range from 300 to 1000 K. As a result of the inter-cluster interactions both glissile and sessile clusters can be obtained and this depends on the metal, reaction type and size of the clusters. In general the probability to form sessile clusters increases for larger clusters and it is higher in Cu. The results obtained are discussed from the point of view of the difference in radiation damage effects in fee Cu and bcc Fe. (C) 2000 Elsevier Science B.V. All rights reserved.