Exceptional enhancement of mechanical properties in high-entropy alloys via thermodynamically guided local chemical ordering
GWALANI, Bharat
Physical and Computational Sciences Directorate
Department of Materials Science and Engineering
Physical and Computational Sciences Directorate
Department of Materials Science and Engineering
LIN, Wei-Chih
Department of Materials Science and Engineering
Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
Department of Materials Science and Engineering
Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
YEH, An-Chou
Department of Materials Science and Engineering
High Entropy Materials Center
PhD. Program in Prospective Functional Materials Industry,
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Department of Materials Science and Engineering
High Entropy Materials Center
PhD. Program in Prospective Functional Materials Industry,
Langue
en
Article de revue
Ce document a été publié dans
Proceedings of the National Academy of Sciences of the United States of America. 2023, vol. 120, n° 23, p. e2211787120
National Academy of Sciences
Résumé en anglais
Understanding the local chemical ordering propensity in random solid solutions, and tailoring its strength, can guide the design and discovery of complex, paradigm-shifting multicomponent alloys. First, we present a simple ...Lire la suite >
Understanding the local chemical ordering propensity in random solid solutions, and tailoring its strength, can guide the design and discovery of complex, paradigm-shifting multicomponent alloys. First, we present a simple thermodynamic framework, based solely on binary enthalpies of mixing, to select optimal alloying elements to control the nature and extent of chemical ordering in high-entropy alloys (HEAs). Next, we couple high-resolution electron microscopy, atom probe tomography, hybrid Monte-Carlo, special quasirandom structures, and density functional theory calculations to demonstrate how controlled additions of Al and Ti and subsequent annealing drive chemical ordering in nearly random equiatomic face-centered cubic CoFeNi solid solution. We establish that short-range ordered domains, the precursors of long-range ordered precipitates, inform mechanical properties. Specifically, a progressively increasing local order boosts the tensile yield strengths of the parent CoFeNi alloy by a factor of four while also substantially improving ductility, which breaks the so-called strength–ductility paradox. Finally, we validate the generality of our approach by predicting and demonstrating that controlled additions of Al, which has large negative enthalpies of mixing with the constituent elements of another nearly random body-centered cubic refractory NbTaTi HEA, also introduces chemical ordering and enhances mechanical properties.< Réduire
Mots clés en anglais
High entropy alloys
Thermodynamics
Chenical ordering
Origine
Importé de halUnités de recherche