Revisiting the fragile-to-strong crossover in metallic glass-forming liquids: application to Cu${}_x$Zr${}_x$Al${}_{100-2x}$

Abstract

The fragile-to-strong crossover seems to be a general feature of metallic glass-forming liquids. Here, we study the behavior of shear viscosity, diffusion coefficient and vibrational density of states for Cu${}_{\text{x}}$Zr${}_{\text{x}}$Al${}_{\text{100-2x}}$ alloy through molecular dynamics simulations. The results reveal that the fragile-to-strong temperature (T${}_{\text{fs}}$) and the glass transition temperature (T${}_{\text{g}}$) increase as the aluminum content becomes larger. The inverse of the diffusion coefficient as a function of temperature exhibits a dynamical crossover in the vicinity of T${}_{\text{g}}$, at a much lower temperature than that predicted by nearly all previous studies. At the temperature in which the dynamical crossover occurs determined by the inverse of the diffusion coefficient, we found an excess of vibrational states at low frequencies, resembling a pronounced peak in the reduced vibrational density of states characteristic of a strong liquid. Finally, the behavior of the shear viscosity as a function of reduced temperature (T${}_{\text{g}}$/T) also shows that, besides the fragile-to-strong crossover nearby T${}_{\text{g}}$, another dynamical crossover is present near the onset of the supercooled regime.

arXiv comment8 pages, 7 figures

References in corpus (8)

• Fragile-to-strong transition and polyamorphism in the energy landscape of liquid silica
• The first principles calculation of transport coefficients
• Free energy and configurational entropy of liquid silica: fragile-to-strong crossover and polyamorphism
• Variation of the glass transition temperature with rigidity and chemical composition
• Understanding the problem of glass transition on the basis of elastic waves in a liquid
• Slow Dynamics in Glasses
• Dynamical, structural and chemical heterogeneities in a binary metallic glass-forming liquid
• Revisiting Dynamics Near a Liquid-Liquid Phase Transition in Si and Ga: The Fragile-to-Strong Transition

Cited by in corpus (2)

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