DOE Share: $1,199,940.00
Performer Share: $299,988.00
Total Award Value: $1,499,928.00
Performer website: - http://www.ge.com
Despite the importance of creep-fatigue-environment interactions, they are not well understood. The project will develop and demonstrate computational algorithms for alloy property predictions, and will model key mechanisms that contribute to the damage caused by creep-fatigue-environment interactions.
The project team will build upon existing expertise, data, and materials modeling tools to develop multiscale (time and volume) computational algorithms and guidelines to understand and predict the response of creep-fatigue-environment interactions and the chemical/mechanical response of nickel-based Haynes 282 superalloy at the temperatures and pressure ranges expected in an A-USC steam turbine.
Program Background and Project Benefits
The U.S. Department of Energy (DOE) promotes the advancement of computational capabilities to develop materials for advanced fossil energy power systems. The DOE’s National Energy Technology Laboratory (NETL) Advanced Research (AR) Program is working to enable the next generation of Fossil Energy (FE) power systems. One goal of the AR Materials Program is to conduct research leading to a scientific understanding of high-performance materials capable of service in the hostile environments associated with advanced ultrasupercritical (A-USC) coal-fired power plants.
A-USC plants will increase coal-fired power plant efficiency by allowing operation at increased temperatures and pressures up to 760 degrees Celsius [1400 degrees Fahrenheit; °F] and 35 megapascals [5,000 pounds force per square inch]. Additionally, A-USC combined with oxycombustion will provide a carbon dioxide (CO2)-ready stream for CO2 capture.
In order to develop boiler and steam turbine materials technology for A-USC systems, materials need to be able to withstand and operate at A-USC conditions for at least 20 years. NETL has teamed with General Electric (GE) Global Research, GE Energy, and a University of Pennsylvania project team to address an important aspect of materials design and service life prediction in future A-USC power plants—the creep-fatigue environment interactions in steam turbine rotor materials.
The methods developed in the project are expected to be applicable to other metal alloys in similar steam/oxidation environments. Haynes 282 was selected for this project because it is one of the leading candidate materials for the high temperature/pressure section of an A-USC steam turbine. This project will help provide better materials for fossil energy production that can withstand higher temperatures and pressures and provide better creep resistance. The technology developed in this project is expected to enable more accurate prediction of long service life of advanced alloys for A-USC power plants and provide faster and more effective materials design, development, and implementation than current state-of-the-art computational and experimental methods.
Goals and Objectives
The goal of this project is to model creep-fatigue-environment interactions in steam turbine rotor materials for A-USC coal power plants, develop and demonstrate computational algorithms for alloy property predictions, and determine and model key mechanisms that contribute to the damage caused by creep-fatigue-environment interactions. The technology developed in this project is expected to enable more accurate predictions of long service life of advanced alloys for A-USC power plants and provide faster and more effective materials design, development, and implementation than current state-of-the-art computational and experimental methods.
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.