Modeling isolated dislocations is challenging due to the need to accurately capture both atomistic details of the dislocation cores as well as their long-range strain fields. The flexible boundary conditions (FBC) approach is a multiscale method which accounts for the long-range response of the dislocation by coupling the core to an infinite harmonic bulk through the lattice Green function (LGF). We develop a numerical method to compute the LGF which can explicitly account for the topology of the lattice around a dislocation and local variations in chemical composition. Using the LGF within the FBC approach coupled with DFT, we are able to perform the first fully atomistic DFT relaxations of dissociated dislocations in a Ni-based superalloy.
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