Multiscale modeling of polycrystalline nickel based superalloys accounting for subgrain microstructures
Abstract This paper focusses on the use of the parametrically homogenized crystal plasticity to simulate polycrystalline ensembles of Ni based superalloys that are governed by the characteristics of the subgrain scale g g' precipitate morphology. Critical parameters representing the effect of subgrain scale morphology are incorporated in the grain scale crystal plasticity model, which then has the capability of representing mechanisms occurring at three scales, viz. the sub grain scale of precipitates, the grain scale of single crystals and the scale of polycrystalline aggregates in a unified framework. A dislocation density crystal plasticity constitutive model with APB shearing of g' precipitates is developed for modeling the sub grain scale representative volume element delineating explicit morphology of the g g' microstructure. A framework is developed for a parametrically homogenized activation energy based crystal plasticity (AE CP) model at the scale of single crystals by homogenizing the sub grain model response and incorporating critical morphological parameters of the sub grain morphology. Nucleation and evolution models for micro twins are also incorporated for manifesting tension compression asymmetry. The grain scale AE CP model is used to analyze polycrystalline microstructures.