Cellular dislocation patterning during plastic deformation

A simulation of dislocation patterning in a two-dimensional multislip configuration is carried out by means of coarse graining in the presence of plastic strain. In order to study the influence of climb on the dislocation cell pattern formation, fatigue simulations with and without climb mobility are performed and compared. The main result is that, in the presence of climb, cellular structures with well-defined characteristic length emerge, in contrast to the self-similar dislocation patterns developing under similar deformation conditions in the absence of climb. Despite the simplicity of our model, the fractal dimension of the self-similar dislocation patterns emerging without climb confirms the previous results for fcc crystals deformed in a multislip configuration. The cell structures emerging when climb is not negligible (in our simulations a climb mobility 1000 times smaller than the glide mobility was considered) resemble the dislocation patterns seen in thermal recovery or melt-grown experiments.