ICAMS / Interdisciplinary Centre for Advanced Materials Simulation
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Sublattice solubility of transition metals in L12 phases in Co-based superalloys

Date: 02.04.2014
Place: DPG Spring Meeting 2014, Dresden, Germany

Jörg Koßmann
Thomas Hammerschmidt
Sascha Maisel, Department of product-oriented materials development, Technische Universität Hamburg-Harburg, Hamburg, Germany
Stefan Müller, Hamburg University of Technology, TUHH, Hamburg, Germany
Ralf Drautz

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(Alx,TM1-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.

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