Crystal-Symmetry Effect on Configurational Entropy and High-Entropy Crystal Structures Stability

Project: Research

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In general, the entropy of a material can be decomposed into configurational, vibrational, electronic, and magnetic entropies. The entropies differ for body-centered-cubic (BCC), face centered-cubic (FCC), hexagonal-close-packed (HCP), and other crystal structures. Among them, the configurational entropy calculations borrowed from the ideal gas mixing remain the same for all crystal structures. For many years, this difference was neglected in the theorems of traditional physical metallurgy with the dilute solid-solution assumption, but it should no longer be ignored for high-entropy alloys (HEAs), which are composed of at least five elements in equiatomic or non-equiatomic percentages. However, precise definition for crystal configurational entropy is unknown. Distinguishing configurational entropy differences not only provides a possible explanation for current critical issues of superior strength-toughness combinations in cryogenic HEAs and FCC-to-HCP phase transition in highly-pressurized HEAs, but also challenges the traditional computations of entropy across metallurgy, crystallography, statistical mechanics, and all other related research fields.


Project number7005068
Effective start/end date1/09/18 → …