Spurious forces were shown to arise when dislocations interacted with atom/continuum interfaces in some classes of multi-scale models. This was due to the use of linear elasticity in continuum descriptions of the material deformation and/or of singular dislocation fields. In the case of Al, such forces could attain 500MPa for dislocations situated within a few Å of the interface and could remain significant at distances of some 20Å on the atomistic side and about 15Å on the continuum side of the interface; inhibiting the creation of truly seamless coupling. Replacement of the continuum representation of the dislocation displacement fields by a so-called template of the full atomistic displacement fields within a radius of 50Å was shown to reduce significantly the magnitude and range of the spurious forces. Implementation of the template method permitted dislocations to approach to within less than 10Å of the interface from both the atomistic and continuum sides, thus permitting higher accuracy to be attained in multi-scale simulations as well as reducing the size of the atomistic region.

Analysis and Minimization of Dislocation Interactions with Atomistic/Continuum Interfaces. M.Dewald, W.A.Curtin: Modelling and Simulation in Materials Science and Engineering, 2006, 14[3], 497-514