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| Titel |
Dislocation core modelling in Mg2SiO4 wadsleyite based on the Peierls-Nabarro-Galerkin model |
| VerfasserIn |
Patrick Cordier, Arnaud Metsue, Philippe Carrez, Christophe Denoual, David Mainprice |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250036765
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| Zusammenfassung |
| Wadsleyite is a high-pressure polymorph that is likely to control the rheology of the upper part of the transition zone. Considering the pressures and temperatures of the stability field, deformation experiments are very challenging on this phase and only a few studies have addressed the issue of its deformation mechanisms. Numerical modeling represents today an attractive alternative to the study of plastic deformation. We propose to use a Peierls-Nabarro model combined with a finite-element method in which we introduce two-dimensional generalised stacking fault energies. Several potential slip planes are considered. Our results show that dislocations in wadsleyite can exhibit complex dislocation cores with linear or non-collinear dissociation and even three-dimensional dislocation cores. The calculation of the Peierls stresses gives information on the potential activity of slip systems governing the plasticity of wadsleyite. Our study confirms experimental observations that ½<111>{101} is the easiest slip system in this structure at high pressure and that [100](010) is the second easiest. Both these easily slip systems have dislocations that dissociate into collinear partial dislocations. In contrast [010] dislocations with very large Burgers vector (11.2 Å) are stabilized by complex dissociations involving four partial dislocations. |
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