Polyamorphic transitions in silica glass

Sonneville, Camille; Deschamps, Thierry; Martinet, C.; Ligny, Dominique de; Mermet, A.; Champagnon, B.

doi:10.1016/j.jnoncrysol.2012.12.002

Cited by 36 publications

(13 citation statements)

References 16 publications

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“…Taken together, our results extend considerably earlier evidence for a fragile-to-strong (FS) transition in silica. Such a transition was observed in experiments [20][21][22] and simulations. 25,26,28 Saika-Voivod et al found a FS transition in the potential energy surface 26 and in the energy landscape.…”

Section: Discussionmentioning

confidence: 57%

Fragile-to-strong transition in liquid silica

2016

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We investigate anomalies in liquid silica with molecular dynamics simulations and present evidence for a fragile-to-strong transition at around 3100 K-3300 K. To this purpose, we studied the structure and dynamical properties of silica over a wide temperature range, finding four indicators of a fragile-to-strong transition. First, there is a density minimum at around 3000 K and a density maximum at 4700 K. The turning point is at 3400 K. Second, the local structure characterized by the tetrahedral order parameter changes dramatically around 3000 K from a higher-ordered, lower-density phase to a less ordered, higher-density phase. Third, the correlation time τ changes from an Arrhenius behavior below 3300 K to a Vogel-Fulcher-Tammann behavior at higher temperatures. Fourth, the Stokes-Einstein relation holds for temperatures below 3000 K, but is replaced by a fractional relation above this temperature. Furthermore, our data indicate that dynamics become again simple above 5000 K, with Arrhenius behavior and a classical Stokes-Einstein relation.

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Section: Discussionmentioning

confidence: 57%

Fragile-to-strong transition in liquid silica

2016

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“…Plastic deformation of glasses is associated with volume conservative shear flows and permanent densification of the network [4]. Densification is accommodated, at the expense of the free molar volume, by rearrangements of the glass network on the intermediate structural level (polyamorphic transition) [5]. The free molar volume which varies with the atomic packing density and the Poisson ratio has been identified as a key parameter for the possible maximum densification [6]: highly polymerized structures (open networks with low atomic packing densities and Poisson ratios) can be greatly densified; the overall achievable densification is significantly reduced for depolymerized glasses (higher atomic packing densities and Poisson ratios) [6].…”

Section: Introductionmentioning

confidence: 99%

Local densification of a single micron sized silica sphere by uniaxial compression

et al. 2015

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“…More details on the experimental setup may be found in [32]. A 532 nm YAG/ Nd3+ laser was used as the light source in normal incidence at a power of approximately 5 mW measured on the sample [33]. For each isotherm, spectra were recorded during compression and decompression: it was found that the Brillouin signal was completely reversible and reproducible.…”

Section: Experimental Approach Iii1 Brillouin Spectroscopymentioning

confidence: 99%

On the Influence of Phase Change in Highly Loaded Frictional Contacts

et al. 2020

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Highly loaded lubricated contacts may present a friction plateau on which the friction force becomes independent from the sliding velocity. Although this phenomenon has been known for a long-time, its physical origin remains poorly known. The present paper aims at giving further insight on the physical mechanisms triggering the friction plateau. The study specifically focuses on the influence of pressure on the physical state of the lubricant. An uncoupled experimental approach (rheology, tribology, spectrometry) has been conducted on a model lubricant. The lubricant behavior has been probed both at rest by Brillouin light scattering spectroscopy and dynamically under stationary conditions in a lubricated contact. The first experimental approach led to evidence a transition pressure associated with the lubricant glass transition, which has then been correlated to the lubricant macroscopic response in friction. We show that the onset of the plateau behavior occurs for Hertzian pressures close to the glass transition pressure, corresponding to a very small fraction of lubricant in a "nominal glassy state" within the contact.

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Polyamorphic transitions in silica glass

Cited by 36 publications

References 16 publications

Fragile-to-strong transition in liquid silica

Fragile-to-strong transition in liquid silica

Local densification of a single micron sized silica sphere by uniaxial compression

On the Influence of Phase Change in Highly Loaded Frictional Contacts

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