Predicting size effects in nickel-base single crystal superalloys with the Discrete-Continuous Model

Abstract

The Discrete-Continuous Model, a coupling between dislocation dynamics and finite elements simulations, is used for modelling size effects in the mechanical properties of single-crystal superalloys. Both formation and evolution of the dislocation microstructures are analysed, and the crucial role of the storage of signed dislocations at the interfaces is discussed. The onset of plasticity is found to scale as the inverse of the channel width, and polarised dislocation networks at the interfaces significantly increase the flow stress with respect to a bulk crystal.