Improved Models of Long-Term Creep Behavior of High Performance Structural Alloys for Existing and Advanced Technologies Fossil Energy Power Plants (Crosscutting Technology Research)

In this program, QuesTek Innovations LLC, a leader in the field of computational materials design, proposes to develop a robust creep modeling toolkit that expands its computational Materials by Design® technology, in order to predict the long term creep performance of materials for base alloys and weldments in fossil energy systems under wide thermal and mechanical conditions. Precipitation modeling using thermodynamic databases, e.g., PrecipiCalc® software will provide fundamental quantities that will be used as inputs for upscaling strategies/methods. The ultimate goal will be to establish microstructure sensitive models that capture the different creep mechanisms observed in ferritic steels and integrate the models into QuesTek’s DARPA-AIM efforts to predict the variability of the creep strength as a function of the microstructure and service conditions. In the Phase I effort, the methods proposed have been demonstrated to predict creep life near 100,000 hours of P91 ferritic steels with microstructure inputs obtained from National Institute of Material Science (NIMS). In Phase II, we will expand the tools and exercise them in wider operation conditions including different temperatures and applied stresses in order to predict creep behaviors with over 300,000 hours creep life. Integration of precipitate evolution schemes into the long term material behavior i.e., stability of microstructure and the different phases over long time periods, along with a refined uncertainty quantification of various material and process parameters, will be assessed and calibrated in Phase II. Additionally, the methodology developed would be applicable to alternate material systems and microstructures through additional ‘modules’ that capture the relevant mechanisms of creep. Accurate and efficient quantification of material properties for AUSC boilers will directly enhance the success of DOE’s crosscutting research and new alloy development program and provide significant public benefits.