b'Mitigating Irradiation-assistedA rapid alloy design framework has broad applications to accelerate the design Stress Corrosion Cracking byof irradiation resistant materials.Rapid Alloy Design T his research demonstrated a rapid alloy design framework for developing reactor structural materials. It directly addresses several challenges that lead to long and expensive development cycles of nuclear materials, including complex design space, slow manufacturing of nuclear grade samples, and expensive and time-consuming in-pile tests. A knowledge-based optimization approach was utilized in place of empirical, test-based approaches. By coupling Integrated Computational Materials Engineering, rapid prototyping and fabrication, and out-of-pile testing, material science principles can be established for materials behaviors in extreme conditions. These principles were used to guide materials optimization for improved performance in current reactors and for applications in TOTAL APPROVED AMOUNT:new operation conditions and new types of reactors. The approach is demonstrated $1,713,456 over 3 years by optimization of stainless steels for improved resistance to IASCC, a critical issue concerning reactor safety. The research demonstrated the feasibility of PROJECT NUMBER:using Integrated Computational Materials Engineering for recommendations 19A39-071 of optimization and using advanced manufacturing for rapid prototyping and PRINCIPAL INVESTIGATOR:fabrication. Candidates for stainless steel additives were down-selected and gradient Daniel Schwen samples with varying additive concentrations were printed. A post-processing treatment was developed to ensure the printed material microstructure is similar to CO-INVESTIGATORS: wrought material. Out-of-pile irradiations up to 50 displacements per atom were Lingfeng He, INL performed on the novel alloys. Characterization confirmed the trends in reducing Xiang Liu, INL vacancy mobility predicted by modeling and simulation.Lin Shao, Texas A&M UniversityMiao Song, University of MichiganXiaoyuan Lou, Auburn UniversityYongfeng Zhang, University of WisconsinZhijie Jiao, University of MichiganCOLLABORATOR:Andresen Consulting105'