Regensburg 2022 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 18: Poster Session 2

MM 18.14: Poster

Dienstag, 6. September 2022, 17:30–20:00, P2

Partitioning of transition metals to the γ and γ ′ phase of Co-based superalloys — •Isabel Pietka¹, Andreas Förner², Manuel Köbrich², Steffen Neumeier², Ralf Drautz¹, and Thomas Hammerschmidt¹ — ¹Ruhr-Universität Bochum, Interdisciplinary Centre for Advanced Materials Simulation (ICAMS) — ²Friedrich-Alexander-Universität Erlangen-Nürnberg, Department of Materials Science & Engineering

Single-crystal Co-base superalloys are a promising class of materials in high-pressure high-temperature applications such as blades of gas turbines or jet engines. The superior mechanical properties at high temperatures are a consequence of the underlying γ/γ ′ microstructure. The improvement of the mechanical properties of these alloys is therefore closely tied to an understanding of the influence of alloying elements on the microstructure. In this work, we describe the γ/γ ′ partitioning of different alloying elements, i.e. their preference for the γ matrix or the γ ′ particles of the microstructure. In particular, we determine the energy difference of nearly all 3d, 4d, 5d transition metals (TMs) in Co₃(Al/W) by density functional theory calculations. In very good agreement with results from wavelength-dispersive X-ray spectroscopy and atom probe tomography, we find a preference of early TMs for the γ ′ phase while mid to late TMs show no clear preference. We demonstrate that the findings can be rationalized in terms of band-filling and atomic size differences by moment analysis from bond order potential theory.