Interstitial dislocation loops with Burgers vector of <100>-type were observed in α-iron irradiated by neutrons or heavy ions, and their population increases with increasing temperature. Their effect upon the motion of a ½<111> edge dislocation was reported earlier 1. Results were presented of a molecular dynamics study of interactions between a ½<111> screw dislocation and <100> loops in iron at temperature in the range 100 to 600K. A variety of reaction mechanisms and outcomes were observed and classified in terms of the resulting dislocation configuration and the maximum stress required for the dislocation to break away. The highest obstacle resistance arises when the loop was absorbed to form a helical turn on the screw dislocation line, for the dislocation cannot glide away until the turn closes and a loop was released with the same Burgers vector as the line. Other than one situation found, in which no dislocation-loop reaction occurs, the weakest obstacle strength was found when the original <100> loop was restored at the end of the reaction. The important role of the cross-slip and the influence of model boundary conditions were emphasised and demonstrated by examples.

Reactions between a ½<111> Screw Dislocation and <100> Interstitial Dislocation Loops in Alpha-Iron Modelled at Atomic Scale. D.Terentyev, D.J.Bacon, Y.N.Osetsky: Philosophical Magazine, 2010, 90[7-8], 1019-33