A parallel three-dimensional level-set code was used to simulate the dynamics of isolated dislocation lines and loops in an obstacle-rich environment. This system served as a convenient prototype for those in which extended one-dimensional objects interacted with obstacles and the out-of-plane motion of these objects was the key to understanding their pinning-depinning behavior. In contrast to earlier models of dislocation motion, long-ranged interactions among dislocation segments and obstacles were incorporated in order to study the effect of climb upon dislocation dynamics in the presence of misfitting penetrable obstacles/solutes, as embodied in an effective climb mobility. The main observations were that increasing climb mobility led to more effective pinning by the obstacles, implying increased strengthening. Secondly, decreasing the range of interactions significantly reduced the effect of climb. The dependence of the critical stress upon obstacle concentration and misfit strength was also explored and compared with existing models. In particular, the present results were shown to be in reasonable agreement with the Friedel-Suzuki theory. Finally, the limitations inherent in the simplified model employed here, including the neglect of some lattice effects and the use of a coarse-grained climb mobility, were considered.

Dislocation Climb Strengthening in Systems with Immobile Obstacles - Three-Dimensional Level-Set Simulation Study. Z.Chen, K.T.Chu, D.J.Srolovitz, J.M.Rickman, M.P.Haataja: Physical Review B, 2010, 81[5], 054104