Creep properties and deformation mechanisms of single-crystalline gamma '-strengthened superalloys in dependence of the Co/Ni ratio

Volz N, Zenk C, Karpstein N, Lenz M, Spiecker E, Göken M, Neumeier S (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Philosophical Magazine Taylor & Francis: STM, Behavioural Science and Public Health Titles / Taylor & Francis

DOI: 10.1080/14786435.2021.2017051

Abstract

Co-base superalloys are considered as promising high temperature materials besides the well-established Ni-base superalloys. However, Ni appears to be an indispensable alloying element also in Co-base superalloys. To address the influence of the base elements on the deformation behaviour, high-temperature compressive creep experiments were performed on a single crystal alloy series that was designed to exhibit a varying Co/Ni ratio and a constant Al, W and Cr content. Creep tests were performed at 900 degrees C and 250 MPa and the resulting microstructures and defect configurations were characterised via electron microscopy. The minimum creep rates differ by more than one order of magnitude with changing Co/Ni ratio. An intermediate CoNi-base alloy exhibits the overall highest creep strength. Several strengthening contributions like solid solution strengthening of the gamma phase, effective diffusion coefficients or stacking fault energies were quantified. Precipitate shearing mechanisms differ significantly when the base element content is varied. While the Ni-rich superalloys exhibit SISF and SESF shearing, the Co-rich alloys develop extended APBs when the gamma ' phase is cut. This is mainly attributed to a difference in planar fault energies, caused by a changing segregation behaviour. As a result, it is assumed that the shearing resistivity and the occurring deformation mechanisms in the gamma ' phase are crucial for the creep properties of the investigated alloy series.

Authors with CRIS profile

Carolin Zenk Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Nicolas Karpstein Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Malte Lenz Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Erdmann Spiecker Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Mathias Göken Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Steffen Neumeier Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)

Additional Organisation(s)

Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Interdisziplinäres Zentrum, Center for Nanoanalysis and Electron Microscopy (CENEM)

How to cite

APA:

Volz, N., Zenk, C., Karpstein, N., Lenz, M., Spiecker, E., Göken, M., & Neumeier, S. (2021). Creep properties and deformation mechanisms of single-crystalline gamma '-strengthened superalloys in dependence of the Co/Ni ratio. Philosophical Magazine. https://dx.doi.org/10.1080/14786435.2021.2017051

MLA:

Volz, N., et al. "Creep properties and deformation mechanisms of single-crystalline gamma '-strengthened superalloys in dependence of the Co/Ni ratio." Philosophical Magazine (2021).

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