Unifying interatomic potential, g(r), elasticity, viscosity, and fragility of metallic glasses: analytical model, simulations, and experiments
| Autor: | Alessio Zaccone, Konrad Samwer, A.E. Lagogianni, Zach Evenson, Johannes Krausser |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Statistics and Probability
Materials science Thermodynamics FOS: Physical sciences Interatomic potential 02 engineering and technology Condensed Matter - Soft Condensed Matter Atomic packing factor Radial distribution function 01 natural sciences Shear modulus Fragility 0103 physical sciences 010306 general physics Scaling glasses (structural) plasticity viscoelasticity Condensed Matter - Materials Science Anharmonicity Materials Science (cond-mat.mtrl-sci) Statistical and Nonlinear Physics Disordered Systems and Neural Networks (cond-mat.dis-nn) Condensed Matter - Disordered Systems and Neural Networks 021001 nanoscience & nanotechnology Soft Condensed Matter (cond-mat.soft) Statistics Probability and Uncertainty 0210 nano-technology Glass transition |
| Popis: | An analytical framework is proposed to describe the elasticity, viscosity and fragility of metallic glasses in relation to their atomic-level structure and the effective interatomic interaction. The bottom-up approach starts with forming an effective Ashcroft-Born-Mayer interatomic potential based on Boltzmann inversion of the radial distribution function g(r) and on fitting the short-range part of $g(r)$ by means of a simple power-law approximation. The power exponent $\lambda$ represents a global repulsion steepness parameter. A scaling relation between atomic connectivity and packing fraction $Z \sim \phi^{1+\lambda}$ is derived. This relation is then implemented in a lattice-dynamical model for the high-frequency shear modulus where the attractive anharmonic part of the effective interaction is taken into account through the thermal expansion coefficient which maps the $\phi$-dependence into a $T$-dependence. The shear modulus as a function of temperature calculated in this way is then used within the cooperative shear model of the glass transition to yield the viscosity of the supercooled melt as a double-exponential function of $T$ across the entire Angell plot. The model, which has only one adjustable parameter (the characteristic atomic volume for high-frequency cage deformation) is tested against new experimental data of ZrCu alloys and provides an excellent one-parameter description of the viscosity down to the glass transition temperature. Comment: Special Issue on Structure in Glassy and Jammed Systems |
| Databáze: | OpenAIRE |
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