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arXiv · 2007.12546

Atomic-scale expressions for viscosity and fragile-strong behavior in metal alloys based on the Zwanzig-Mountain formula

Giovanni Chevallard·Konrad Samwer·Alessio Zaccone
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Abstract

We combine the shoving model of $T$-dependent viscosity of supercooled liquids with the Zwanzig-Mountain formula for the high-frequency shear modulus, using the $g(r)$ of MD simulations of metal alloys as the input. This scheme leads to a semi-analytical expression for the viscosity as a function of temperature, which provides a three-parameter model fitting of experimental data of viscosity for the same alloy for which $g(r)$ was calculated. The model provides direct access to the influence of atomic-scale physical quantities such as the interatomic potential $\phi(r)$, on the viscosity and fragile-strong behavior. In particular, it is established that a steeper interatomic repulsion leads to fragile liquids, or, conversely, that "soft atoms make strong liquids".

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cond-mat.softcond-mat.dis-nncond-mat.mtrl-scicond-mat.stat-mechphysics.chem-ph

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Giovanni Chevallard, Konrad Samwer, Alessio Zaccone. 2020-07-24. Atomic-scale expressions for viscosity and fragile-strong behavior in metal alloys based on the Zwanzig-Mountain formula. https://doi.org/10.1103/physrevresearch.2.033134

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