The coupled atomistic/discrete-dislocation method in 3d. Part III: Dynamics of hybrid dislocations

In two companion papers, the CADD-3d method for coupling atomistic and discrete dislocations was described and validated for (quasi-)static equilibrium. Here, CADD-3d is validated further for the time evolution of straight and curved hybrid dislocations, i.e. dislocations that span both atomistic and continuum domains simultaneously. Studies show physically sensible results when using precise calibration of the discrete dislocation mobility and atomistic core structures, and the sensitivity of results when intentional deviations away from the precise calibrations are used. CADD-3d is then used to model the evolution of dislocation loops from atomistic Frank-Read sources under sustained load. The predicted nucleation and expansion of multiple loops is in excellent agreement with fully atomistic simulations at small scales. CADD-3d is then applied to much larger scales that capture both the nucleation of loops at the atomic scale and the evolution of a dislocation loop pile-ups at the micron scale, with full interactions among all dislocations in the system during the entire time evolution. Collectively, the results here serve to demonstrate the accuracy, robustness, and power of CADD-3d, and point toward its future application in many complex dislocation problems requiring both atomistic resolution and large-scale dislocation evolution. (C) 2018 Elsevier Ltd. All rights reserved.