This is a $500,000.00 research grant awarded by the National Aeronautics and Space Administration (NASA) to The Ohio State University. The objective is to develop advanced computational models that integrate process parameters, microstructural evolution, and material properties to predict the weld quality and performance for self-reacting friction stir welding (FSW). The approach involves creating a microstructure-integrated material model, a hybrid fluid dynamics-solid mechanics process model, and integrating precipitate evolution and structure-property relationships to predict weld strength. The models will be validated through in-situ process monitoring, multi-scale weld characterization, and mechanical testing. The potential impacts include transforming the FSW process development route using physics-based models, creating an integrated software tool for process engineers, and significantly advancing the application of integrated computational materials engineering (ICME) in solid-state manufacturing. This grant was not set aside for any specific business classification.