Fundamental of High Entropy Alloy: computationally guided material design

We propose a comprehensive effort aimed at understanding the fundamentals of high entropy (HE) alloys, in particular, thermodynamics of alloy formation, stability, and deformation mechanism at high temperature. The effort can be further divided into two categories: 1) theoretical: develop a thermodynamic model for alloy formation and predict alloy stability using density functional theory (DFT) approach, and 2) experimental: synthesize known HE-alloys, systematically characterize microstructure and mechanical and physical properties, especially the mechanical properties at elevated temperature. These efforts are designed to answer some of the pressing questions, such as what is the correct value of mixing enthalpy and what is the origin of high strength at high temperature. Strategically, these efforts foster PNNL's capacity for HE-alloy development and establish PNNL as one of the key contributor in this young field.
HE-alloys promise exceptional mechanical properties such as great machinability, high strength and excellent corrosion resistance at elevated temperature. A refractory HE-alloy promises to replace the expensive super-alloys used in gas turbine and the expensive Inconel alloys used in applications like a coal gasification heat exchanger. A light-weight HE-alloy promises to replace titanium, aluminum and magnesium alloys for land based vehicles and airplanes. It is apparent that a successfully developed HE-alloy will have huge impact on the United States (U.S.) energy and transportation industries. The proposed research aimed at developing novel energy materials that promise higher energy conversion efficiency and lower environmental impact. This research directly addresses the scientific issues in energy conversion and energy conservation and is fully consistent with the Environmental Molecular Science Laboratory (EMSL) mission "(to) develop sustainable sources of clean energy and chemicals". Moreover, it is well aligned with the components of the science theme call in science of interfacial phenomena, which aims to support, "studies that enable the development of molecular level understanding and predictive models of critical interface properties related to energy production and storage" and "combined methods (including linking modeling with experiment), novel approaches, and/or in situ studies that help advance the fundamental understanding of chemical processes at complex interfaces associated with advanced materials for energy or materials/biological interfaces"?.