Dislocation properties of coesite from an<i>ab-initio</i>parametrized interatomic potential

Giacomazzi, Luigi; Carrez, Philippe; Scandolo, Sandro

doi:10.1103/physrevb.83.014110

Cited by 9 publications

(10 citation statements)

References 51 publications

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“…This can be informed by the difference of Poisson’s ratio, where the one of normal ice is slightly higher than that of methane hydrate ( Table S3 ). Furthermore, Peierls stresses of the slip plane 35 in methane hydrate should be much higher than those in normal ice, since the methane hydrate has much larger crystalline unit cell than normal ice. In fact, the methane hydrate deforms vertically approximately 10 6 times slower than normal ice 15 .…”

Section: Resultsmentioning

confidence: 99%

“…This result is the same as that of preceding experimental findings 11 12 , but it differs from recent compressive creep tests 14 15 , where the methane hydrate is more than 20–40 times stronger than normal ice. In this regard, dislocation motion on the easy glide systems should be investigated 35 38 . Finally, methane hydrate is a typical inclusion compound in the H-bond network, and an understanding of the strain-hardening behaviour in this compound may assist further studies of strain hardening in polymers, where the polymer network contributes to strain hardening but requires an explanation of additional mechanisms to understand fully the temperature effects 39 .…”

Section: Discussionmentioning

confidence: 99%

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Microscopic Origin of Strain Hardening in Methane Hydrate

Jia

Liang

Tsuji

et al. 2016

Sci Rep

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It has been reported for a long time that methane hydrate presents strain hardening, whereas the strength of normal ice weakens with increasing strain after an ultimate strength. However, the microscopic origin of these differences is not known. Here, we investigated the mechanical characteristics of methane hydrate and normal ice by compressive deformation test using molecular dynamics simulations. It is shown that methane hydrate exhibits strain hardening only if the hydrate is confined to a certain finite cross-sectional area that is normal to the compression direction. For normal ice, it does not present strain hardening under the same conditions. We show that hydrate guest methane molecules exhibit no long-distance diffusion when confined to a finite-size area. They appear to serve as non-deformable units that prevent hydrate structure failure, and thus are responsible for the strain-hardening phenomenon.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Microscopic Origin of Strain Hardening in Methane Hydrate

Jia

Liang

Tsuji

et al. 2016

Sci Rep

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“…(2001). However, recent simulation results of ab‐initio calculation on dislocations in coesite suggest that [001](010), [100](010) and [101](010) are similar slip systems in coesite in terms of lattice friction as a result of its pseudohexagonal symmetry (Giacomazzi et al. , 2011).…”

Section: Discussionmentioning

confidence: 99%

Petrofabric and strength of SiO₂ near the quartz‐coesite phase boundary

Zhang¹,

Shi²,

Xu³

et al. 2012

Journal Metamorphic Geology

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Quartz and coesite constitute an important portion of deep subducted continental upper crust. However, the rheology and petrofabric of quartz and coesite are not well constrained under high-pressure (HP) ⁄ ultrahigh-pressure (UHP) metamorphic conditions both in laboratory and in nature. We report here the first deformation microstructure and lattice preferred orientations of garnet, omphacite, interstitial coesite, quartz and rutile in UHP eclogites from the Yangkou Bay, Sulu UHP terrane, as well as fabric development of quartz and coesite in shear experiments at P-T conditions near the quartzcoesite phase boundary. Our results show: (i) garnet and coesite develop weak to random fabric while omphacite, quartz and rutile develop pronounced fabrics in deformed natural eclogites; (ii) quartz develops fabrics in responding to a dominant c-slip with increasing shear strain under HP ⁄ UHP conditions; (iii) coesite develops fabrics in responding to a dominant [100](010) slip with increasing shear strain under UHP conditions; and (iv) the relative strengths of major constituent minerals in continental deep subduction zones are quartz < omphacite < coesite. These results are consistent with the rheology determined in the laboratory for quartz, jadeite ⁄ omphacite and coesite. We propose that jadeite ⁄ omphacite dominates the rheology and seismic anisotropy of deeply subducted continental crust.

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“…Dislocation core modelling can be based either on fully atomistic simulations (based on either empirical potentials or electronic structure calculations) or on the Peierls-Nabarro (PN) model where the core structure emerges from the equilibrium in the core region between elastic and inelastic forces [33,34]. In this study, we use the PNG method [32,35] as implemented in the Cod 2 ex software which offers the possibility to take multiple glide planes into account and to calculate complex (possibly three-dimensional) dislocation cores [36][37][38][39]. As in the initial PN model or in recent generalizations [40][41][42][43], the dislocation core structure is determined from the minimization of elastic energy (through an approximation of a continuous field representation) and an interplanar potential derived from g-surfaces calculations.…”

Section: Dislocation Core Modellingmentioning

confidence: 99%

Modelling the effect of pressure on the critical shear stress of MgO single crystals

Amodeo

Carrez

Cordier

2012

Philosophical Magazine

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We use a hierarchical multi-scale model to study the effect of high pressure on the critical shear stresses of MgO. The two main slip systems, ½<110>{110} and ½<110>{100} are considered. Based on a generalized Peierls-Nabarro model, we show that the core structure of ½<110> screw dislocations is strongly sensitive to pressure. Mostly planar and spread in {110} at ambient pressure, the core of screw dislocations tends to spread in {100} with increasing pressure. Subsequently, one observes an inversion of the easiest slip systems between 30 and 60 GPa. At high pressure, the plasticity of MgO single crystals is expected to be controlled by ½<110>{100} slip systems, except at high temperature where both slip systems become active. Pressure is also found to increase the critical resolved shear stresses and to shift the athermal temperature toward higher temperatures. Under high pressure, MgO is thus characterized by a significant lattice friction on both slip systems.

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Dislocation properties of coesite from anab-initioparametrized interatomic potential

Cited by 9 publications

References 51 publications

Microscopic Origin of Strain Hardening in Methane Hydrate

Microscopic Origin of Strain Hardening in Methane Hydrate

Petrofabric and strength of SiO₂ near the quartz‐coesite phase boundary

Modelling the effect of pressure on the critical shear stress of MgO single crystals

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Dislocation properties of coesite from anab-initioparametrized interatomic potential

Cited by 9 publications

References 51 publications

Microscopic Origin of Strain Hardening in Methane Hydrate

Microscopic Origin of Strain Hardening in Methane Hydrate

Petrofabric and strength of SiO2 near the quartz‐coesite phase boundary

Modelling the effect of pressure on the critical shear stress of MgO single crystals

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Petrofabric and strength of SiO₂ near the quartz‐coesite phase boundary