RheoMan: a five-year, ERC-funded (Advanced Grant), project to model the rheology of the Earth's mantle

Feb 7, 2014 Publication in Modelling and Simulation in Materials Science and Engineering Results

Modelling [100] and [010] screw dislocations in MgSiO3 perovskite based on the Peierls-Nabarro-Galerkin model

authored by K. Gouriet, P. Carrez & P. Cordier has been published in Modelling and Simulation in Materials Science and Engineering, 025020 (17pp) doi:10.1088/0965-0393/22/2/025020.

In this study, stacking-fault energy calculations are performed in MgSiO3 perovskite using a pairwise potential parametrization. They are compared to previous ab initio results validating the use of pairwise potential for modeling mechanical properties beyond the elastic behavior.

We present γ -surfaces corresponding to (1 0 0), (0 1 0), (0 0 1), (0 1 1) and (1 0 1) planes at 30, 60, 100 and 140 GPa. Check out the supplementary data available from stacks.iop.org/MSMSE/22/025020/mmediawhere most figures are presented.

GSF 100

GSF 010

GSF 001

GSF 011

GSF 101

 

In a second step, generalized stacking-fault energy calculations are introduced into a generalized Peierls–Nabarro model, called Peierls–Nabarro–Galerkin. We model the core structure of screw dislocations with [1 0 0] and [0 1 0] Burgers vector to determine the preferential glide plane for these dislocations. Indeed, the plane where the screw dislocations will spread the more is the one where slip is more likely to occur.

Peierls–Nabarro–Galerkin calculations demonstrate that [1 0 0] and [0 1 0] dislocations are, respectively, characterized by a planar core spreading in (0 1 0) and (1 0 0).

 

 dislocation 100                    dislocation 010

 

Our results emphasize the role of [1 0 0](0 1 0) and [0 1 0](1 0 0) slip systems in the deformation mechanism of MgSiO3 perovskite.