Interaction dynamics between dislocations and radiation-induced sessile self-interstitial atom dislocation loops in face-centered cubic metals were investigated. As a result of dislocation-line flexibility, its equilibrium configuration was found to be sensitive to the elastic field of nearby self-interstitial atom dislocation loops. Dislocation-line flexibility also influenced the critical stress required to free trapped dislocations from pinning atmospheres. The calculated critical resolved shear stress values differed by up to 100% from estimates which were based upon the cluster forces exerted on static rigid dislocations. The mechanism of dislocation-unpinning from random cluster atmospheres was shown to be a result of morphological instabilities on the dislocation line. The initial location of the unlocking instability was always associated with regions of minimum line tension in the vicinity of the lowest cluster density. The growth of dislocation-shape fluctuations led to a sequence of unzipping events which freed the dislocation from the elastic fields of cluster atmospheres. The relative critical shear stress required to unlock dislocations in face-centered cubic metals was found to range from 0.001 to 0.002 for random atmosphere cluster densities of 1024 to 1025m3, and to range from 0.0014 to 0.003 for coherent cluster atmospheres in the same density-range.

The Dynamics of Dislocation Interaction with Sessile Self-Interstitial Atom Defect Cluster Atmospheres. J.Huang, N.M.Ghoniem: Computational Materials Science, 2002, 23[1-4], 225-34