Multiscale modeling of polycrystalline nickel-based superalloys accounting for subgrain microstructures

摘要

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 gamma-gamma' 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 gamma' precipitates is developed for modeling the sub grain scale representative volume element delineating explicit morphology of the gamma-gamma' 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. (C) 2015 Elsevier Ltd. All rights reserved.