Title :

On the glide of [100] dislocation and the origin of ‘pencil glide’ in Mg2SiO4 olivine

Author(s) :

Mahendran, Srinivasan [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Carrez, Philippe [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Cordier, Patrick [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]

Journal title :

Philosophical Magazine

Abbreviated title :

Philosophical Magazine

Volume number :

99

Pages :

2751-2769

Publisher :

Informa UK Limited

Publication date :

2019-07-09

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]

Olivine with chemical composition (Mg,Fe)2SiO4 is a silicate which is supposed to strongly constrain the flow of the Earth’s upper mantle under thermal convection. Its mechanical properties are thus of primary importance. ...
Show more >Olivine with chemical composition (Mg,Fe)2SiO4 is a silicate which is supposed to strongly constrain the flow of the Earth’s upper mantle under thermal convection. Its mechanical properties are thus of primary importance. Slip systems in olivine involve two types of dislocations with [100] and [001] Burgers vectors. In this study, we report atomistic modelling of screw dislocations with [100] Burgers vector and their intrinsic properties. We show that the [100] screw dislocation core exhibits several configurations corresponding to spreading in different planes and different relative stabilities. At low pressure, we identify a clear tendency for core spreading in (010). At higher pressure, relevant for the Earth’s mantle, we show that pressure promotes a change in core configuration with spreading into equivalent {021} planes. Based on the systematic investigation of the minimum energy path between the different configurations, we show that the variability of core structures allows complex glide paths which has been described at the macroscopic level as ‘pencil glide’. Our results suggest that the pencil glide is more efficient at high pressure.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Non spécifiée

European Project :

MULTISCALE MODELLING OF THE RHEOLOGY OF MANTLE MINERALS

Administrative institution(s) :

Université de Lille
CNRS
INRA
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Plasticité

Submission date :

2019-10-07T11:57:55Z
2019-10-10T07:52:49Z
2019-10-10T11:52:47Z