Regensburg 2010 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 12: Topical Session Designing Innovative Structural Materials and Steels III

MM 12.2: Talk

Monday, March 22, 2010, 15:00–15:15, H4

Importance of magnetic effects on structural properties in Al- and Si- substituted Laves phases Fe₂Nb and Fe₂W — •François Liot, Martin Friák, and Jörg Neugebauer — Department for Computational Materials Design, Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf, Germany

Laves phases are promising candidates for the design of new steels with superior mechanical strength. Here we study systematically thermodynamic, structural and magnetic properties in Al- and Si- substituted Laves phase compounds Fe₂Nb and Fe₂W using first-principles density functional methods. Spin polarized calculations predict that substituting Al atoms for Fe atoms in Fe₂Nb is energetically more favorable than substituting Al atoms for Nb atoms. Furthermore, they show that this leads to a significant increase of the lattice constant along the a axis. To investigate the effects of magnetism, non-magnetic calculations are carried out for the same Fe-Nb-Al compounds. Our results show that the inclusion of magnetism is crucial to accurately reproduce experimental data. Based on this insight, theoretical predictions for ternary alloys Fe-Nb-Si, Fe-W-Al and Fe-W-Si are presented.