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Abstract

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.