On the formation mechanisms of intragranular shear bands in olivine by stress-induced amorphization

Idrissi, Hosni; Béché, Armand; Gauquelin, Nicolas; Haq, Ihtasham ul; Bollinger, Caroline; Demouchy, Sylvie; Verbeeck, Johan; Pardoen, Thomas; Schryvers, D.

doi:10.1016/j.actamat.2022.118247

Cited by 9 publications

(3 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has recently been shown that olivine grain boundaries can amorphize and slide under high stress in olivine [1]. Stress-induced intragranular amorphization has also been reported by [2]. Approaching the glass transition temperature, the grain boundary amorphization and sliding mechanism can have a significant impact on the olivine rheology.…”

Section: Introductionmentioning

confidence: 87%

See 1 more Smart Citation

On-Chip Very Low Strain Rate Rheology of Amorphous Olivine Films

Coulombier,

Baral,

Orekhov

et al. 2023

Preprint

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 87%

“…Synthetic, polycrystalline pellets of olivine with a nominal composition of Fe 0.2 Mg 1.8 SiO 4 were ablated using a pulsed laser beam with a frequency of 10 Hz, a wavelength of 192 nm, and at a laser fluence of approximately 5 J/cm 2 . Details on the setup can be found in [7].…”

Section: Pulsed Laser Deposited A-olivinementioning

confidence: 99%

On-Chip Very Low Strain Rate Rheology of Amorphous Olivine Films

Coulombier,

Baral,

Orekhov

et al. 2023

Preprint

View full text Add to dashboard Cite

“…However, we recall that to date, disconnections were never observed as constituent defects of olivine grain boundaries, using transmission electron microscopy, for example, and that a framework explaining their potential mobility still does not exist (e.g., Cahn et al, 2006). On the other side, Volterra disclination identification by TEM was recently proposed by Idrissi et al (2022), and a mobility framework was already established (e.g., Acharya and Fressengeas, 2015;Taupin et al, 2013Taupin et al, , 2014Combe et al, 2016).…”

Section: Disclination Detection Densities and Displaymentioning

confidence: 97%

Dislocation and disclination densities in experimentally deformed polycrystalline olivine

Demouchy

Thieme²,

Barou³

et al. 2023

Eur. J. Mineral.

Self Cite

View full text Add to dashboard Cite

Abstract. We report a comprehensive data set characterizing and quantifying the geometrically necessary dislocation (GND) density in the crystallographic frame (ραc) and disclination density (ρθ) in fine-grained polycrystalline olivine deformed in uniaxial compression or torsion, at 1000 and 1200 ∘C, under a confining pressure of 300 MPa. Finite strains range from 0.11 up to 8.6 %, and stresses reach up to 1073 MPa. The data set is a selection of 19 electron backscatter diffraction maps acquired with conventional angular resolution (0.5∘) but at high spatial resolution (step size ranging between 0.05 and 0.1 µm). Thanks to analytical improvement for data acquisition and treatment, notably with the use of ATEX (Analysis Tools for Electron and X-ray diffraction) software, we report the spatial distribution of both GND and disclination densities. Areas with the highest GND densities define sub-grain boundaries. The type of GND densities involved also indicates that most olivine sub-grain boundaries have a mixed character. Moreover, the strategy for visualization also permits identifying minor GND that is not well organized as sub-grain boundaries yet. A low-temperature and high-stress sample displays a higher but less organized GND density than in a sample deformed at high temperature for a similar finite strain, grain size, and identical strain rate, confirming the action of dislocation creep in these samples, even for micrometric grains (2 µm). Furthermore, disclination dipoles along grain boundaries are identified in every undeformed and deformed electron backscatter diffraction (EBSD) map, mostly at the junction of a grain boundary with a sub-grain but also along sub-grain boundaries and at sub-grain boundary tips. Nevertheless, for the range of experimental parameters investigated, there is no notable correlation of the disclination density with stress, strain, or temperature. However, a broad positive correlation between average disclination density and average GND density per grain is found, confirming their similar role as defects producing intragranular misorientation. Furthermore, a broad negative correlation between the disclination density and the grain size or perimeter is found, providing a first rule of thumb on the distribution of disclinations. Field dislocation and disclination mechanics (FDDM) of the elastic fields due to experimentally measured dislocations and disclinations (e.g., strains/rotations and stresses) provides further evidence of the interplay between both types of defects. At last, our results also support that disclinations act as a plastic deformation mechanism, by allowing rotation of a very small crystal volume.

show abstract

Hole Polaron‐Mediated Suppression of Electron–Hole Recombination Triggers Efficient Photocatalytic Nitrogen Fixation

Li,

Chen,

Sun

et al. 2024

Advanced Materials

View full text Add to dashboard Cite

In the pursuit of successful photocatalytic transformations, challenges persist due to limitations in charge carrier utilization and transfer efficiency, which stemming from rapid recombination. Overcoming these limitations necessitates the exploration of novel mechanisms that enhance the effective separation of photogenerated electron–hole pairs. Herein, deviating from the conventional approach of enhancing carrier migration to separate photogenerated charges and extend their lifetime, the proposal is to directly prevent the recombination of photogenerated electrons and holes by forming hole polarons. Specifically, disordered pores are introduced on the surface of KTaO3 ultrathin sheets, and the clear‐cut evidences in electron paramagnetic resonance, photoluminescence, and ultrafast spectroscopy unambiguously confirm the enhanced carrier–phonon coupling, which results in the formation of hole polarons to impede the recombination of photogenerated electron–hole pairs. Taking the challenging nitrogen oxidation reaction as an example, it is found that the hole polarons in atomic‐disordered pore KTaO3 ultrathin nanosheets trigger outstanding photo‐oxidation performance of nitrogen (N2)to nitrate, with a nitrate‐producing rate of 2.1 mg g−1 h−1. This scenario is undoubtedly applicable to a wide variety of photocatalytic reactions due to the common challenge of charge carrier recombination in all photocatalytic processes, manifesting broad implications for promoting photocatalysis performance.

show abstract

On the formation mechanisms of intragranular shear bands in olivine by stress-induced amorphization

Cited by 9 publications

References 39 publications

On-Chip Very Low Strain Rate Rheology of Amorphous Olivine Films

On-Chip Very Low Strain Rate Rheology of Amorphous Olivine Films

Dislocation and disclination densities in experimentally deformed polycrystalline olivine

Hole Polaron‐Mediated Suppression of Electron–Hole Recombination Triggers Efficient Photocatalytic Nitrogen Fixation

Contact Info

Product

Resources

About