Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 25: Microstructure and Phase Transformations III
MM 25.3: Vortrag
Dienstag, 27. März 2012, 12:15–12:30, H 0106
Martensitic phase transition of iron — •Bertrand Dupé1,2, Bernard Amadon1, Christophe Denoual1, and Yves-Patrik Pellegrini1 — 1CEA, DAM, DIF, F-91297 Arpajon, France — 2Institue of Theoretical Physics and Astronomy, University of Kiel, 24098 Kiel Germany
Even if Iron is a long studied element, several of its properties remain puzzling. One of them is the mechanism of martensitic phase transition from the bcc to hcp Phases. Even in the simplest description, a shuffle and a shear are involved in this transition [1]. Several authors have described the kinetic of the transition, using Minimum Energy Path calculations with ab initio calculations[2-4] with different physical assumptions for the coupling between shuffle and shear [3,4].
In this study, we propose a new path for the transition based on ab initio calculations. We discuss the path with respects to the NEB method. Our ab initio calculations also suggest that this transition might not involve a cooperative motion of atoms in contradiction to the common rule for martensitic transitions. The key role of magnetic ordering during the transition will be also adressed suggesting a more complex Ferromagnetic to Antiferromagnetic behaviour as previously seen [3,5].
[1] Burgers, W. G. Physica, 1934, 1, 561 [2]Ekman et al Phys. Rev. B, 1998, 58, 5296 [3] Johnson, D. F. & Carter, E. A. Journ. Chem. Phys., 2008, 128, 104703 [4] Liu, J. B. & Johnson, D. D. Phys. Rev. B, 2009, 79, 134113 [5] Friák, M. & Šob, M. Phys. Rev. B, 2008, 77, 174117