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 and vacancy diffusivity prediction with quantum physics-based DFT calculations 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 will be demonstrated on a specific material class of ferritic steels, but the methodology developed would be applicable to alternate material systems and microstructures through additional ‘modules’ that capture the relevant mechanisms of creep. In Phase II, we will expand the tools and exercise them in wider applications with various materials systems. Additionally, 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. 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. Key words:Long-term creep, precipitation coarsening, 9% Cr ferritic steel, PrecipiCalc, continuum damage model, ThermoCalc, Questek innovations.