|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Coupling Experiments and Modeling to Understand Plasticity and Failure
||E-2: An Image Based Finite Element Model for Ni-based Superalloys Using a Two Scale Constitutive Model Accounting for Morphological Distributions of γ’ Precipitates
||George Weber, Maxwell Pinz, Akbar Bagri, Somnath Ghosh
|On-Site Speaker (Planned)
A polycrystalline crystal plasticity finite element model is developed for γ-γ’ nickel-based superalloys with constitutive behavior established over two length scales. A dislocation density-based crystal plasticity model, at the subgrain scale, is implemented to explicitly simulate the complex two-phase morphology and include the effects of dominant thermomechanical micromechanisms. By generating a series of γ-γ’ statistically-equivalent representative volume elements (SERVEs), the sensitivity of the micromechanical response to distributions of local geometric features of the precipitates is understood. Through a parametric-homogenization scheme coupled with uncertainty-analysis techniques, a single-crystal homogenized constitutive law is developed to account for the morphology of the precipitate-matrix substructure without explicitly representing the two-phase geometry. This multiscale framework is implemented to study the performance of polycrystalline microstructures under monotonic and fatigue loading. Weak regions of the polycrystal, susceptible to crack nucleation, are strengthened by locally varying the γ-γ’ substructures, linking design of superalloys to material processing across length scales.
||Planned: Supplemental Proceedings volume