Dresden 2017 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 16: Computational Materials Modelling - Novel Materials

MM 16.1: Vortrag

Montag, 20. März 2017, 15:45–16:00, IFW B

Ab initio derived phase stabilities for the design of novel Ce-based hard-magnetic materials — •Halil ibrahim Sözen, Fritz Körmann, Tilmann Hickel, and Jörg Neugebauer — Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany

Due to the developments in electrical transportation and renewable energies, hard magnetic materials composed of rare earths (RE) and transition metals (TM) have gained increasing importance in the last decades. Recently, there are attempts to develop alternative hard magnetic materials, RE-TM-X (X=Ti, W, Mo, Si, Al), that lift the dependence on a small number of RE elements. In order to support the efforts to find alternative materials concepts for hard magnetic applications, we performed ab initio calculations of finite temperature phase stabilities of Ce-based alloys. The Helmholtz free energy F(T,V) is calculated for all relevant competing phases using a sophisticated set of methods capturing vibrational, electronic, magnetic and configurational entropy contributions. The study includes unary Ce, binaries of Ce-Fe and Fe-Ti phases, and ternary Ce-Fe-Ti phases, for which the performance of our approach for rare-earth metals is tested. We observe that the presence of the CeFe2 phase retards any formation of promising Ce-Fe-Ti alloys. The study has therefore been extended to the impact of fourth alloying elements such as Cu and La, in order to provide strategies to solve this challenge.