Titre :

Characterization of recovery onset by subgrain and grain boundary migration in experimentally deformed polycrystalline olivine

Auteur(s) :

NZOGANG, Billy Clitton [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Thieme, Manuel [Auteur]
Géosciences Montpellier
Mussi, Alexandre [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Demouchy, Sylvie [Auteur]
Géosciences Montpellier
Cordier, Patrick [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]

Titre de la revue :

European Journal of Mineralogy

Nom court de la revue :

Eur. J. Mineral.

Numéro :

32

Pagination :

13-26

Éditeur :

Copernicus GmbH

Date de publication :

2020-01-15

Statut de l’article :

Publié

ISSN :

1617-4011

Discipline(s) HAL :

Planète et Univers [physics]/Sciences de la Terre/Minéralogie

Résumé en anglais : [en]

Abstract. To apprehend plate tectonics and the dynamics of the lithosphere–asthenosphere boundary, composed principally of olivine, we need to understand the mechanisms that control plastic deformation of olivine in the ...
Lire la suite >Abstract. To apprehend plate tectonics and the dynamics of the lithosphere–asthenosphere boundary, composed principally of olivine, we need to understand the mechanisms that control plastic deformation of olivine in the relevant temperature domain. After more than 50 years of laboratory studies and investigations on natural rocks, the interplay of several key parameters (e.g. temperature, pressure, vacancy concentration, dislocation densities, grain size, strain rate) controlling polycrystalline olivine plasticity remains difficult to assess. Here, we study four olivine polycrystals, which have been deformed in axial compression under a confining pressure of 300 MPa, at 1273 or 1473 K. Despite significant differences in mechanical properties (stress–strain curves), previous characterization by scanning (SEM) and transmission electron microscopy (TEM) did not reveal significant differences in dislocation microstructures which could explain these contrasted behaviours. We have undertaken automatic crystallographic orientation mapping (ACOM) analyses in TEM to increase the spatial resolution of characterization compared to previously obtained electron backscatter diffraction maps to further decipher the microstructures at nanoscale. With this novel technique applied to olivine, a noticeable difference in the onset of microstructural recovery has been identified between specimens deformed at 1273 and 1473 K. The microstructures of the olivine polycrystals deformed at 1473 K exhibit numerous curved grain and subgrain boundaries, advocating for recovery by boundary migration. In contrast, the microstructures of the olivine polycrystals deformed at 1273 K have significantly fewer subgrain boundaries and show more straight boundaries (i.e. closer to an equilibrium microstructure) than in the specimen deformed at 1473 K. Characterization by ACOM-TEM has permitted the identification of the onset of recovery, which is led by boundary migration even for very low macroscopic finite strains.Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Non spécifiée

Références liée(s) :

http://hdl.handle.net/20.500.12210/18215

Projet Européen :

MULTISCALE MODELLING OF THE RHEOLOGY OF MANTLE MINERALS

Établissement(s) :

Université de Lille
CNRS
INRA
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Équipe(s) de recherche :

Plasticité

Date de dépôt :

2020-01-15T16:47:24Z
2020-01-20T13:21:06Z
2020-12-15T11:37:50Z