CCS and Power Systems
Crosscutting Research - Plant Optimization Technologies
Modeling Creep-Fatigue-Environment Interactions in Stream Turbine Rotor Materials for Advanced Ultras
Performer: General Electric Company
Project No: FE0005859
The research team is developing a fundamental understanding of the fatigue failure mechanisms in the nickel-based Haynes 282 superalloy, including an understanding of the fatigue threshold of the superalloy. GE has started work on a mesoscale microstructure-based crack model. Atomic level modeling has been performed on grain boundary chemistry and structure with a focus on oxygen energetics and mobility and its impact on oxide formation.
The project team has investigated the crack growth response of Haynes 282 as a function of test temperature, cyclic period, environment, and the applied delta K value. Both creep-fatigue and environmental-fatigue interactions were found to be operative depending upon test temperature. A phase field model framework is being built to treat mesoscale crack growth, polycrystalline microstructure, oxygen diffusion, and oxidation concurrently. This initial work demonstrated the ability to treat stress fields of cracks in an elastically anisotropic and inhomogeneous polycrystal using the phase field microelasticity theory. The project team has also developed a model for the creep behavior of Haynes 282 as a function of time, temperature, and applied stress. This model shows good agreement with experimental creep data over the range of temperatures and applied stresses that would be encountered in A-USC applications. At a larger length scale the project team has also started to develop a FORTRAN-based confined crack tip plasticity model based on the evolution equations for the near crack tip plastic deformation response. The team calibrated the model against finite element modeling results of near crack tip plasticity.