The Dislocation-Structure and Crystallite-Size in Forsterite (Olivine) Deformed at 1400 °C by 11 GPa

Nyilas, K.; Couvy, H.; Cordier, Patrick; Ungár, Tamás

doi:10.1524/zksu.2006.suppl_23.135

Cited by 7 publications

(5 citation statements)

References 12 publications

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“…We calculated the theoretical contrast factors on the basis of the crystallography of dislocations [ Borbély et al , 2003], extended to the orthorhombic system [ Cordier et al , 2004; Nyilas et al , 2006], using the elastic constants of MgGeO 3 post‐perovskite at 80 GPa [ Usui et al , 2010]. Numerical values of the theoretical contrast factors for all dislocation types we studied are listed in Table 2.…”

Section: Dislocations Analysismentioning

confidence: 99%

High resolution three‐dimensional X‐ray diffraction study of dislocations in grains of MgGeO₃ post‐perovskite at 90 GPa

Nisr¹,

Ribárik²,

Ungár³

et al. 2012

J. Geophys. Res.

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[1] MgGeO 3 post-perovskite (pPv) is a lower pressure analogue of MgSiO 3 -pPv, which is believed to be the main constituent of the Earth's D″ layer. Understanding the physical properties of this phase is critical to explain seismological observations as seismic anisotropy is likely linked to lattice preferred orientation in post-perovskite, which is governed by the motion of defects such as dislocations. Here, we apply in-situ three-dimensional X-ray diffraction to a polycrystalline sample of MgGeO 3 -pPv at 90 GPa. We demonstrate how the method can be used to follow individual grains within the material, including their individual orientations, positions, and strain tensors. We then use X-ray line profile analysis to characterize dislocations in the grains. The most probable slip systems are

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Section: Dislocations Analysismentioning

confidence: 99%

High resolution three‐dimensional X‐ray diffraction study of dislocations in grains of MgGeO₃ post‐perovskite at 90 GPa

Nisr¹,

Ribárik²,

Ungár³

et al. 2012

J. Geophys. Res.

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“…Although, so far, these scaling laws have only been tested on metals, it is still interesting to note that they were found to be quite robust being independent of material properties such as stacking fault energy, solute content, etc., and process parameters such as temperature, strain, strain rate, strain paths, etc., suggesting a rather universal behavior. Intragranular misorientations can be detected in the reciprocal space through X‐ray peak broadening which can be analyzed to provide average measurements of strain, including dislocation densities (Nyilas et al, ) and even information on Burgers vectors and slip systems (Cordier et al, ; Nisr et al, ). In the real space, scanning electron microscope (SEM)‐based Electron Backscattered Electron Diffraction (EBSD) provides a very efficient and largely automated technique to sample long‐range and short‐range information on misorientations within deformed samples.…”

Section: Introductionmentioning

confidence: 99%

Characterization by Scanning Precession Electron Diffraction of an Aggregate of Bridgmanite and Ferropericlase Deformed at HP‐HT

Nzogang

Bouquerel

Mussi

et al. 2018

Geochem Geophys Geosyst

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Scanning precession electron diffraction is an emerging promising technique for mapping phases and crystal orientations with short acquisition times (10–20 ms/pixel) in a transmission electron microscope similarly to the Electron Backscattered Diffraction (EBSD) or Transmission Kikuchi Diffraction (TKD) techniques in a scanning electron microscope. In this study, we apply this technique to the characterization of deformation microstructures in an aggregate of bridgmanite and ferropericlase deformed at 27 GPa and 2,130 K. Such a sample is challenging for microstructural characterization for two reasons: (i) the bridgmanite is very unstable under electron irradiation, (ii) under high stress conditions, the dislocation density is so large that standard characterization by diffraction contrast are limited, or impossible. Here we show that detailed analysis of intracrystalline misorientations sheds some light on the deformation mechanisms of both phases. In bridgmanite, deformation is accommodated by localized, amorphous, shear deformation lamellae whereas ferropericlase undergoes large strains leading to grain elongation in response to intense dislocation activity with no evidence for recrystallization. Plastic strain in ferropericlase can be semiquantitatively assessed by following kernel average misorientation distributions.

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“…The theoretical values of parameter q for pure edge and screw dislocations are determined by the elastic constants and the dislocation slip systems activated in the crystal [104]. For orthorhombic crystals the average contrast factors can be expressed as [90,105]:…”

Section: X-ray Line Profile Analysismentioning

confidence: 99%

Defect structure in plastically deformed high-entropy alloys

Heczel¹

2018

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The Dislocation-Structure and Crystallite-Size in Forsterite (Olivine) Deformed at 1400 °C by 11 GPa

Cited by 7 publications

References 12 publications

High resolution three‐dimensional X‐ray diffraction study of dislocations in grains of MgGeO₃ post‐perovskite at 90 GPa

High resolution three‐dimensional X‐ray diffraction study of dislocations in grains of MgGeO₃ post‐perovskite at 90 GPa

Characterization by Scanning Precession Electron Diffraction of an Aggregate of Bridgmanite and Ferropericlase Deformed at HP‐HT

Defect structure in plastically deformed high-entropy alloys

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The Dislocation-Structure and Crystallite-Size in Forsterite (Olivine) Deformed at 1400 °C by 11 GPa

Cited by 7 publications

References 12 publications

High resolution three‐dimensional X‐ray diffraction study of dislocations in grains of MgGeO3 post‐perovskite at 90 GPa

High resolution three‐dimensional X‐ray diffraction study of dislocations in grains of MgGeO3 post‐perovskite at 90 GPa

Characterization by Scanning Precession Electron Diffraction of an Aggregate of Bridgmanite and Ferropericlase Deformed at HP‐HT

Defect structure in plastically deformed high-entropy alloys

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High resolution three‐dimensional X‐ray diffraction study of dislocations in grains of MgGeO₃ post‐perovskite at 90 GPa

High resolution three‐dimensional X‐ray diffraction study of dislocations in grains of MgGeO₃ post‐perovskite at 90 GPa