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

镍基高温合金具有许多与美国经济和国防相关的关键应用，包括商用和军用喷气发动机、燃气轮机和发电机。这些材料可以在相对高的温度下操作，但是通常由于它们在最高操作温度下的不良性能而限制了它们的应用。为了设计能够承受不断升高的温度的高温合金，首先有必要了解这些合金在微观层面上发生了什么。该奖项支持基础研究，以了解控制高温合金行为的微观过程，以及开发强大的计算工具来预测这种行为和设计高性能材料。该方法利用独特的高通量方法进行实验表征，再加上数据驱动的计算方法，可以计算这些高温合金的相稳定性。该项目将培养下一代材料科学家和工程师，他们具有强大的材料加工专业知识以及计算和实验技能，以更好地为美国制造业服务。本研究的总体目标是建立一个新的范式，用于可靠有效地评估过程中金属间相的热力学稳定性。这一目标将通过以下方法实现：1）对具有多个子晶格的复杂拓扑密堆积（TCP）相的单个子晶格中的子晶格稳定性和原子相互作用能量进行高通量的第一性原理计算（维科夫位点）不能通过实验直接测量; 2）探索创新的和系统的策略，使第一原理结果能够容易地结合到相图的计算中; 3）进行高通量扩散倍数以获得对TCP相稳定性评估至关重要的三元体系的可靠相图，并采用该数据来优化相的吉布斯能参数;以及4）扩展基础设施能力以无缝地使用第一原理计算结果和实验数据来执行高通量相图计算，包括不确定性量化。除了建立一个新的模式，在相图建模，这项研究的成果包括有价值的相图的重要三元系统获得的扩散倍数，以及一组可靠的TCP相的吉布斯能函数，其从实验相图和密度泛函理论（DFT）预测两者建模，可以并入Ni的热力学数据库中。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.