Multiscale modelling of MgO single crystal plasticity


 ...From the laboratory conditions to the Earth's mantle

Dr. Jonathan Amodeo

23. January 2013, 17.00
WW8, Raum 2.018, Dr.-Mack-Str. 77, Fürth

Surface geological events, like volcanos and earthquakes, are due to the internal dynamics of the Earth which tends to release its internal heat. Inside the Earth's mantle, solid rocks are plastically strained under extreme conditions of pressure, temperature and strainrate. In spite of recent experimental progress, it is still impossible to reach such conditions of deformation. That is why we propose an alternative approach, based on the multi-scale modeling of plasticity, from the laboratory conditions to the Earth's mantle. We have choosen to apply our model to magnesium oxide which is a phase present in the lower mantle. From core properties, we modeled a dislocation thermally activated mobility law based on the kink pair theory. Then, we have incorporated it inside a Dislocation Dynamics code to describe the collective behaviour of dislocations throughout numerical strain experiments. Here we show that MgO mechanical properties depends significantly on pressure and strainrate.