Martinez E., Marian J., Arsenlis A., Perlado J.M. Atomistically informed dislocation dynamics in fee crystals

Article, Chemistry and Materials Science Directorate, Lawrence Livermore National Laboratory, Livermore; Instituto de Fusion Nuclear, Universidad Politecnica de Madrid, Madrid, Spain, 27 pp.
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We develop a nodal dislocation dynamics (DD) model to simulate plastic processes in fee crystals. The model explicitly accounts for all slip systems and Burgers vectors observed in fee systems, including stacking faults and partial dislocations. We derive simple conservation rules that describe all partial dislocation interactions rigorously and allow us to model and quantify cross-slip processes, the structure and strength of dislocation junctions, and the formation of fee-specific structures such as stacking fault tetrahedra. The DD framework is built upon isotropic non-singular linear elasticity and supports itself on information transmitted from the atomistic scale. In this fashion, connection between the meso and micro scales is attained self-consistently, with all material parameters fitted to atomistic data. We perform a series of targeted simulations to demonstrate the capabilities of the model, including dislocation reactions and dissociations and dislocation junction strength. Additionally we map the four-dimensional stress space relevant for cross-slip and relate our findings to the plastic behavior of monocrystalline fee metals.