Incorporating the interaction of dislocations with obstacles remains a challenge in the development of predictive large-scale plasticity models. The need was particularly important in the elastic–plastic transition region where these interactions could dominate the behavior. By combining post-mortem analysis with dynamic straining in the transmission electron microscope, the atomic processes governing glissile dislocation reactions and interactions with obstacles was determined. This information was incorporated at least phenomenologically in models to assess the macroscopic stress–strain response. Two examples will be presented to demonstrate the methodology. The first example considers the interaction of dislocations with small vacancy Frank loops and the formation of defect-free channels in copper, and the second with the influence of imperfect annealing twin boundaries on the macroscopic stress–strain response in Ag. In both examples, the importance of grain and twin boundaries as dislocation sources will be demonstrated.

Dislocation–Obstacle Interactions - Dynamic Experiments to Continuum Modeling. I.M.Robertson, A.Beaudoin, K.Al-Fadhalah, C.M.Li, J.Robach, B.D.Wirth, A.Arsenlis, D.Ahn, P.Sofronis: Materials Science and Engineering A, 2005, 400-401, 245-50