Dresden 2017 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 34: Poster session II
MM 34.14: Poster
Dienstag, 21. März 2017, 18:30–20:30, P4
Impact of magnetism on the stability of Laves phases in Fe-Nb alloys — •Ali Zendegani1, Alvin N. Ladines2, Thomas Hammerschmidt2, Ralf Drautz2, Fritz Körmann1, Tilmann Hickel1, and Jörg Neugebauer1 — 1Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf, Germany — 2ICAMS, Ruhr-Universität Bochum, 44801 Bochum, Germany
Ferritic steels containing Fe-Nb Laves phases have a number of industrially relevant high-temperature applications, e.g., for automotive industry. The Laves phases play a decisive role for the high-temperature strength of these materials. To tailor their mechanical characteristics, e.g., via heat treatments, a precise knowledge of the Laves phase thermodynamic stability is essential.
We have investigated the phase stability of the three different Laves phases in Fe-Nb alloys, i.e. hexagonal C14 and C36, and cubic C15, combining density functional theory and thermodynamic concepts. The ground state energy as well as finite temperature entropy contributions of these structures are evaluated for various magnetic configurations, ranging from non-magnetic simulations over selected ferro/ferri-magnetic ones to fully paramagnetic calculations. We discuss the challenges and methodological advances developed for such computations.