Collaborative Research: Accurate Prediction of Phase Stability for Chemistry and Process Design of Ni-based Superalloys

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Nickel-based superalloys have a number of critical applications relevant to the US economy and national defense, including commercial and military jet engines, gas turbines, and power generators. These materials can operate at relatively high temperatures, but often are limited in their application by their poor performance at the highest operating temperatures. In order to design superalloys that can withstand ever increasing temperatures, it is necessary first to understand what happens at the microscopic level in these alloys. This award supports fundamental research to understand the microscopic processes that control superalloy behavior at high temperatures, and the development of robust computational tools to predict this behavior and design high-performance materials. The approach takes advantage of a unique high-throughput approach to experimental characterization, coupled with a data-driven computational approach to enable the calculation of phase stability in these superalloys. This project will educate next-generation materials scientists and engineers with strong materials processing expertise and both computational and experimental skills to better serve the U.S. manufacturing industry.The overall objective of this research is to establish a new paradigm for reliable and effective assessments of the thermodynamic stability of intermetallic phases during process. This objective will be achieved by: 1) performing high-throughput first-principles calculations of sublattice stabilities and atomic interaction energetics in individual sublattices of the complex topological close-packed (TCP) phases with multiple sublattices (Wyckoff sites) that cannot be directly measured experimentally; 2) exploring innovative and systematic strategies to enable facile incorporation of first-principles results into calculation of phase diagrams ; 3) making high-throughput diffusion multiples to obtain reliable phase diagrams of ternary systems critical to TCP phase stability evaluation, and employing the data to optimize the Gibbs energy parameters of the phases; and 4) expanding the infrastructure capabilities to seamlessly use both first-principles calculation results and experimental data to perform high-throughput phase diagram calculations, including uncertainty quantifications. In addition to establishing a new paradigm in phase diagram modeling, the outcomes of this study include valuable phase diagrams of important ternary systems obtained from diffusion multiples, and a set of reliable Gibbs energy functions for the TCP phases modeled from both experimental phase diagrams and density functional theory (DFT) predictions that can be incorporated into thermodynamic databases for Ni-based superalloys.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.