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MM: Fachverband Metall- und Materialphysik

MM 37: Computational Materials Modelling V - Point defects

MM 37.3: Talk

Wednesday, April 2, 2014, 10:45–11:00, IFW D

Sublattice solubility of transition metals in L1₂ phases in Co-based superalloys — •Jörg Koßmann¹, Thomas Hammerschmidt¹, Sascha Maisel², Stefan Müller², and Ralf Drautz¹ — ¹ICAMS, Ruhr-University Bochum, Bochum, Germany — ²Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg, Germany

Superalloys are a class of advanced materials that are used e.g. to cast turbine blades for aircraft engines because of their good mechanical stability even at high temperatures. They owe their high-temperature toughness to hardening by precipitation of γ^′ particles (L1₂ structure) which coexist with the coherent γ phase (disordered fcc). Since Sato et al. first observed a L1₂ phase in the ternary Co-Al-W system, Co-based materials have been shown to be promising candidates for the next generation of superalloys. We investigate the solubility of the transitions metals (TM) W, Mo, Cr, Ti, and Ta in L1₂-Co₃(Al_x,TM_1−x) with density functional theory calculations. For the description of the sublattice disorder we use the cluster expansion and special quasi-random structures. This work is part of the collaborative research center SFB/TR 103.