|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Computational Methods for Spatio-temporal Scale-bridging: from Atomistics to Mesoscale
||Peierls Potential and Kink Pair Mechanism in High Pressure MgSiO3 Perovskite
||Philippe Carrez, Antoine Kraych, Pierre Hirel, Patrick Cordier
|On-Site Speaker (Planned)
The study of plastic properties of minerals is of primary importance to model Earth’s mantle rheology, responsible for plate tectonics and related phenomena. Numerical simulations provide an alternative to deformation experiments to address the behaviour of materials under extreme (P,T) conditions. In this study, we focus on dislocation kink pairs mechanism in MgSiO3 perovskite (main constituent of the Earth’s mantle). We rely on a hierarchical multi scale model to study the effect of high pressure on the critical resolved shear stresses of MgSiO3. Atomistic calculations based on the nudge elastic band method evidence some peculiar features of the Peierls potential: Peierls potential is shown to be dynamically asymmetric and dependent on the applied stress. Kink pairs nucleation enthalpies are further calculated using an elastic interaction model parametrized on atomistic simulations. Results of this multi-scale model are finally compared to recent evaluations of the shear stresses in high pressure deformation experiments.
||Planned: A print-only volume