Diffusion Characteristics of Clusters of Self-Interstitial Atoms
 in Vanadium: Molecular Dynamics Data

Abstract

The temperature dependences of diffusion characteristics of the irradiation-induced defects, namely, clusters of self-interstitial atoms (SIAs) containing up to five atoms, in bcc V (vanadium) have been studied by the method of molecular dynamics in the temperature range of 300–1000 K. The diffusion characteristics include the coefficient of diffusion, the tracer correlation factor, the average displacement before changing the direction of migration, and the frequency of changing the direction of migration. The values of the activation energy of diffusion and the activation energy of changing the direction of migration for the considered types of defects in different temperature ranges have been determined. The dependences of the mechanism of (1D vs 3D) diffusion of SIA clusters on the temperature and cluster size and their possible influence on the parameters of phenomenological models of changes in the microstructure of a material under irradiation (sink strengths of spherical absorbers) are discussed.