Title :

Prediction of Mechanical Twinning in Magnesium Silicate Post-Perovskite

Author(s) :

Carrez, Philippe [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Goryaeva, Alexandra M. [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Cordier, Patrick [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]

Journal title :

Scientific reports

Volume number :

7

Pages :

2475

Publication date :

2017-12-15

HAL domain(s) :

Planète et Univers [physics]/Sciences de la Terre
Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]

English abstract : [en]

The plastic properties of MgSiO3 post-perovskite are considered to be one of the key issues necessary for understanding the seismic anisotropy at the bottom of the mantle in the so-called D” layer. Although plastic slip ...
Show more >The plastic properties of MgSiO3 post-perovskite are considered to be one of the key issues necessary for understanding the seismic anisotropy at the bottom of the mantle in the so-called D” layer. Although plastic slip in MgSiO3 post-perovskite has attracted considerable attention, the twinning mechanism has not been addressed, despite some experimental evidence from low-pressure analogues. On the basis of a numerical mechanical model, we present a twin nucleation model for post-perovskite involving the emission of 1/6 <110> partial dislocations. Relying on first-principles calculations with no adjustable parameters, we show that {110} twin wall formation resulting from the interaction of multiple twin dislocations occurs at a twinning stress comparable in magnitude to the most readily occurring slip system in post-perovskite. Because dislocation activities and twinning are competitive strain-producing mechanisms, twinning should be considered in future models of crystallographic preferred orientations in post-perovskite to better interpret seismic anisotropy in the lowermost lower mantle.Show less >

Language :

Anglais

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
ENSCL
CNRS
INRA

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Plasticité

Submission date :

2019-05-16T17:21:33Z
2024-05-14T07:07:18Z