Unifying interatomic potential, g(r), elasticity, viscosity, and fragility of metallic glasses: analytical model, simulations, and experiments
2016 | journal article. A publication with affiliation to the University of Göttingen.
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Unifying interatomic potential, g(r), elasticity, viscosity, and fragility of metallic glasses: analytical model, simulations, and experiments
Lagogianni, A. E.; Krausser, J.; Evenson, Z.; Samwer, K. H. & Zaccone, A. (2016)
Journal of Statistical Mechanics Theory and Experiment, 2016(8) art. 084001. DOI: https://doi.org/10.1088/1742-5468/2016/08/084001
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Details
- Authors
- Lagogianni, A. E.; Krausser, Johannes; Evenson, Z.; Samwer, Konrad H.; Zaccone, Alessio
- Abstract
- 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 similar to 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.
- Issue Date
- 2016
- Status
- published
- Publisher
- Iop Publishing Ltd
- Journal
- Journal of Statistical Mechanics Theory and Experiment
- Project
- info:eu-repo/grantAgreement/EC/FP7/607080/EU/Vitrified Metals Technologies and Applications in Devices and Chemistry/VitriMetTech
- Organization
- Fakultät für Physik
- eISSN
- 1742-5468
- ISSN
- 1742-5468
- Language
- English
- Sponsor
- EU through VitrimetTech ITN network [FP7-PEOPLE-2013-ITN-607080]