Nano-scale defect clusters, such as voids, dislocation loops, stacking-fault tetrahedra and irradiation-induced precipitates, were produced in metals by irradiation with high-energy atomic particles. They were obstacles to dislocation glide and could give rise to substantial changes in the yield and flow stresses and ductility. Atomic-scale computer simulation was able to provide detail of how these effects were influenced by obstacle structure, applied stress, strain rate and temperature. Some recent results from modelling dislocations interacting with obstacles were described. Emphasis was placed on dislocation interaction with voids, copper precipitates and dislocation loops in body-centered cubic iron and stacking fault tetrahedra in face-centered cubic copper. In the latter case, the importance of surfaces in reactions in TEM foils was highlighted. It was shown that while some atomic processes could be represented adequately by the continuum theory of crystal defects, others could not.

Dislocation-Obstacle Interactions at Atomic Level in Irradiated Metals. D.J.Bacon, Y.N.Osetsky: Mathematics and Mechanics of Solids, 2009, 14[1-2], 270-83