Microsegregation and precipitates of an as-cast Co-based superalloy-microstructural characterization and phase stability modelling

Kossmann J, Zenk C, Lopez-Galilea I, Neumeier S, Kostka A, Huth S, Theisen W, Göken M, Drautz R, Hammerschmidt T (2015)

Publication Language: English

Publication Type: Journal article

Publication year: 2015

Journal

Journal of Materials Science Springer Verlag (Germany)

Book Volume: 50

Pages Range: 6329-6338

Journal Issue: 19

DOI: 10.1007/s10853-015-9177-8

Abstract

The demand for increased efficiency of industrial gas turbines and aero engines drives the search for the next generation of materials. Promising candidates for such new materials are Co-based superalloys. We characterize the microsegregation and solidification of a multi-component Co-based superalloy and compare it to a ternary Co–Al–W compound and to two exemplary Ni-based superalloys by combining the experimental characterization of the as-cast microstructures with complementary modelling of phase stability. On the experimental side, we characterize the microstructure and precipitates by electron microscopy and energy-dispersive X-ray spectroscopy and determine the element distributions and microsegregation coefficients by electron probe microanalysis (EPMA). On the modelling side, we carry out solidification simulations and a structure map analysis in order to relate the local chemical composition with phase stability. We find that the microsegregation coefficients for the individual elements are very similar in the investigated Co-based and Ni-based superalloys. By interpreting the local chemical composition from EPMA with the structure map, we effectively unite the set of element distribution maps to compound maps with very good contrast of the dendritic microstructure. The resulting compound maps of the microstructure in terms of average band filling and atomic-size difference explain the formation of topologically close-packed phases in the interdendritic regions. We identify B2, C14, and D024 precipitates with chemical compositions that are in line with the structure map.

Authors with CRIS profile

Carolin Zenk Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Steffen Neumeier Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Mathias Göken Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)

Additional Organisation(s)

Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)

Related research project(s)

Single crystal y/y'-hardened Co-base superalloys - alloy development, heat treatment strategies and mechanical properties (B03) (SFB/TRR 103) SFB/TRR 103: Vom Atom zur Turbinenschaufel - wissenschaftliche Grundlagen für eine neue Generation einkristalliner Superlegierungen Jan. 1, 2012 - Dec. 31, 2015

Involved external institutions

Ruhr-Universität Bochum (RUB) DE Germany (DE) Max-Planck-Institut für Eisenforschung GmbH (MPIE) / Max Planck Institute for Iron Research DE Germany (DE)

How to cite

APA:

Kossmann, J., Zenk, C., Lopez-Galilea, I., Neumeier, S., Kostka, A., Huth, S.,... Hammerschmidt, T. (2015). Microsegregation and precipitates of an as-cast Co-based superalloy-microstructural characterization and phase stability modelling. Journal of Materials Science, 50(19), 6329-6338. https://dx.doi.org/10.1007/s10853-015-9177-8

MLA:

Kossmann, J., et al. "Microsegregation and precipitates of an as-cast Co-based superalloy-microstructural characterization and phase stability modelling." Journal of Materials Science 50.19 (2015): 6329-6338.

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