Title :

Deformation of Polycrystalline MgO Up to 8.3 GPa and 1270 K: Microstructures, Dominant Slip-Systems, and Transition to Grain Boundary Sliding

Author(s) :

Ledoux, Estelle [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Lin, Feng [Auteur]
University of Utah
Miyagi, Lowell [Auteur]
University of Utah
Addad, Ahmed [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Fadel, Alexandre [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Jacob, Damien [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
béclin, franck [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Merkel, Sébastien [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]

Journal title :

Frontiers in Earth Science

Abbreviated title :

Front. Earth Sci.

Volume number :

10

Pages :

849777

Publisher :

Frontiers Media SA

Publication date :

2022-05-09

ISSN :

2296-6463

English keyword(s) :

MgO
deformation
electron microscopy
slip systems
grain boundary sliding
lattice preferred orientation
lower mantle
anisotropy

HAL domain(s) :

Chimie/Matériaux
Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Physique [physics]/Physique [physics]/Géophysique [physics.geo-ph]
Physique [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Sciences de la Terre

English abstract : [en]

Ferropericlase is the second most abundant mineral in the Earth’s lower mantle and its mechanical properties have a strong influence on the rheology of this region. Here, we deform polycrystalline MgO, the magnesium ...
Show more >Ferropericlase is the second most abundant mineral in the Earth’s lower mantle and its mechanical properties have a strong influence on the rheology of this region. Here, we deform polycrystalline MgO, the magnesium end-member of ferropericlase, at conditions ranging from 1.6 to 8.3 GPa and 875–1,270 K. We analyse the flow laws and microstructures of the recovered samples using electron microscopy and compare our observations with predictions from the literature. We identify a first mechanism for samples deformed at 1,270 K, attributed to a regime controlled by grain boundary sliding accommodated by diffusion, and characterized by a small grain size, an absence of texture, and no intracrystalline deformation. At 1,070 K and below, the deformation regime is controlled by dislocations. The samples show a more homogeneous grain size distribution, significant texture, and intracrystalline strains. In this regime, deformation is controlled by the ⟨110⟩{110} slip system and a combined ⟨110⟩{110} and ⟨110⟩{100} slip, depending on pressure and temperature. Based on these results, we propose an updated deformation map for polycrystalline MgO at mantle conditions. The implications for ferropericlase and seismic observations in the Earth’s lower mantle are discussed.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

ANR Project :

Transformations de phase, microstructures, et leur signatures sismiques dans le manteau terrestre

Administrative institution(s) :

Université de Lille
CNRS
INRAE
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Matériaux Terrestres et Planétaires
Métallurgie Physique et Génie des Matériaux

Submission date :

2022-05-09T07:50:53Z
2022-05-10T15:17:27Z