Configurational Entropy Effects on Glass Transition in Metallic Glasses.
J Phys Chem Lett
; 13(33): 7889-7897, 2022 Aug 25.
Article
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| ID: mdl-35979998
ABSTRACT
Configurational entropy (Sconf) is known to be a key thermodynamic factor governing a glass transition process. However, this significance remains speculative because Sconf is not directly measurable. In this work, we demonstrate the role of Sconf theoretically and experimentally by a comparative study of a Zr-Ti-Cu-Ni-Be high-entropy metallic glass (HE-MG) with one of its conventional MG counterparts. It is revealed that the higher Sconf leads to a glass that is energetically more stable and structurally more ordered. This is manifested by ab initio molecular dynamics simulations, showing that â¼60% fewer atoms are agitated above Tg, and experimental results of smaller heat capacity jump, inconspicuous stiffness loss, insignificant structural change during glass transition, and a more depressed boson peak in the HE-MG than its counterpart. We accordingly propose a model to explain that a higher Sconf promotes a faster degeneracy-dependent kinetics for exploration of the potential energy landscape upon glass transition.
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MEDLINE
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2022
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Article