Berlin 2018 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 22: Microstructure and Phase Transformations
MM 22.2: Vortrag
Dienstag, 13. März 2018, 10:30–10:45, TC 010
Stabilization of body-centred cubic iron under Earth’s core conditions — •Sergei I. Simak — Linköping University (LiU), 58183 Linköping, Sweden
The Earth’s solid core is mostly composed of iron. However, the stable phase of iron under inner-core conditions remains uncertain. The two leading candidates are hexagonal close-packed (hcp) and body-centred cubic (bcc) crystal structures, but the dynamic and thermodynamic stability of bcc iron under inner-core conditions has recently been challenged. We demonstrate the stability of the bcc phase of iron under conditions consistent with the centre of the core using ab initio molecular dynamics simulations. We find that the bcc phase is stabilized at high temperatures by a novel diffusion mechanism that arises due to the dynamical instability of the phase at lower temperatures1.
1 A. B. Belonoshko, T. Lukinov, J. Fu, J. Zhao, S. Davis, and S. I. Simak, "Stabilization of body-centred cubic iron under inner-core conditions", Nature Geoscience 10, 312 (2017).