Creep of Crystals

Poirier, Jean

doi:10.1017/cbo9780511564451

Cited by 929 publications

(334 citation statements)

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“…The yield points cannot be detected here because they lie at such low confining pressures that stage I cannot be clearly observed. Note that the shear moduli for NaC1 (26 GPa) and Cu3Au (45 GPa, calculated from the values for Cu and Au weighted by the appropriate stoichiometry) are quite similar, and that the pressure dependence of the shear modulus is higher for NaCI than for Cu3Au (2.1 versus 1.6) (Poirier, 1985). The shear moduli should thus become equal around 1.4 GPa.…”

Section: Figurementioning

confidence: 92%

Compression Behaviour of Elastically Anisotropic Polycrystals Using Energy-Dispersive X-ray Diffraction

Otto¹,

Vassiliou²,

Frommeyer³

1997

J Synchrotron Radiat

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The compression behaviour of a foil of Cu3Au in a pressure medium of NaC1 has been studied by energy-dispersive X-ray diffraction in a diamond-anvil cell. Evidence from stress analysis and peak broadening of the foil (the most extreme example of a non-ideal powder) throws light on the compression of powders under non-hydrostatic conditions. A complete pressure cycle, including re-pressurization after pressure release, shows that significant plastic deformation takes place which results in large deviations from a (hydrostatic) equation of state. The origin of the deformations is traced to shear stresses transmitted to the sample through the pressure medium.

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Section: Figurementioning

confidence: 92%

Compression Behaviour of Elastically Anisotropic Polycrystals Using Energy-Dispersive X-ray Diffraction

Otto¹,

Vassiliou²,

Frommeyer³

1997

J Synchrotron Radiat

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“…The first basis for this has been given by (Frost and Ashby, 1982), who have shown that choosing a proper normalization for stress and temperature (usually Page 4 of 31 A c c e p t e d M a n u s c r i p t 4 stress is normalized to the shear modulus and temperature to the melting temperature although Poirier (1985) emphasizes rightly that this choice is not unique), allows the construction of deformation-mechanism maps. A possible inference from these maps is that under the same normalized conditions, materials belonging to the same isomechanical group would exhibit the same dominant deformation mechanism.…”

Section: (R2) For Thismentioning

confidence: 99%

Numerical modelling of dislocations and deformation mechanisms in CaIrO3 and MgGeO3 post-perovskites—Comparison with MgSiO3 post-perovskite

Metsue

Carrez

Mainprice

et al. 2009

Physics of the Earth and Planetary Interiors

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Please cite this article as: Metsue, A., Carrez, P., Mainprice, D., Cordier, P., Numerical modelling of dislocations and deformation mechanisms in CaIrO 3 and MgGeO 3 postperovskites -Comparison with MgSiO 3 post-perovskite, Physics of the Earth and Planetary Interiors (2007), doi:10.1016/j.pepi.2008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A c c e p t e d M a n u s c r i p t 2 Abstract:In this study, we propose a theoretical approach to test the validity of the isomechanical analogues for post-perovskite structures. Intrinsic plastic properties are evaluated for three materials exhibiting a post-perovskite phase: MgSiO 3 , MgGeO 3 and CaIrO 3 .Dislocation properties of each structure are determined using the Peierls-Nabarro model based on first principles calculations of generalised stacking fault and the plastic properties are extended to crystal preferred orientations using a visco-plastic selfconsistent method. This study provides intrinsic parameters of plastic deformation such as dislocation structures and Peierls stresses that can be directly compared between the three materials. It appears that it is very difficult to draw any simple conclusions on polycrystalline deformation simply by comparing single crystal properties. In particular, contrasting single crystal properties of MgSiO 3 and CaIrO 3 lead to similar crystal preferred orientation of the polycrystal aggregates.

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“…Polygonization often can be identified by occurrence of more nearest-neighbor grains with small misorientations than would occur randomly in a sample. (Poirier ( 1985 ) distinguished between the formation of new grains by subdividing, which he called "creep polygonization", and the refinement of this structure by further deformation, which he called "rotation recrystallization". Here I use "polygonization" to refer to both.…”

Section: Journal Qf Glaciologymentioning

confidence: 99%

Flow-law hypotheses for ice-sheet modeling

1992

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ABSTRACT. Ice-flow modeling requires a flow law relating strain rates to stresses in situ, but a flow law cannot be measured directly in ice sheets. Microscopic processes such as dislocation glide and boundary diffusion control both the flow law for ice and the development of physical properties such as grain-size and c-axis fabric. These microscopic processes can be inferred from observations of the physical properties, and the flow law can then be estimated from the microscopic processes.A review of available literature shows that this approach can be imperfectly successful. Interior regions of large ice sheets probably have depth-varying flow-law "constants", with the stress exponent, n, for power-law creep less than 3 in upper regions and equal to 3 only in deep ice; n probably equals 3 through most of the thickness of ice shelves and ice streams.

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Creep of Crystals

Cited by 929 publications

References 0 publications

Compression Behaviour of Elastically Anisotropic Polycrystals Using Energy-Dispersive X-ray Diffraction

Compression Behaviour of Elastically Anisotropic Polycrystals Using Energy-Dispersive X-ray Diffraction

Numerical modelling of dislocations and deformation mechanisms in CaIrO3 and MgGeO3 post-perovskites—Comparison with MgSiO3 post-perovskite

Flow-law hypotheses for ice-sheet modeling

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