On the diffusive phase transformation mechanism assisted by extended dislocations during creep of a single crystal CoNi-based superalloy

Makineni SK, Kumar A, Lenz M, Kontis P, Meiners T, Zenk C, Zaefferer S, Eggeler G, Neumeier S, Spiecker E, Raabe D, Gault B (2018)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2018

Journal

Acta Materialia Elsevier

Pages Range: 362-371

DOI: 10.1016/j.actamat.2018.05.074

Abstract

We propose here a deformation-induced diffusive phase transformation mechanism occurring during shearing of γ′ ordered phase in a γ/γ′ single crystalline CoNi-based superalloy. Shearing involved the creation and motion of a high density of planar imperfections. Through correlative electron microscopy and atom probe tomography, we captured a superlattice intrinsic stacking fault (SISF) and its associated moving leading partial dislocation (LPD). The structure and composition of these imperfections reveal characteristic chemical – structural contrast. The SISF locally exhibits a D019 ordered structure coherently embedded in the L12 γ′ and enriched in W and Co. Interestingly, the LPD is enriched with Cr and Co, while the adjoining planes ahead of the LPD are enriched with Al. Quantitative analysis of the three-dimensional compositional field in the vicinity of imperfections sheds light onto a new in-plane diffusion mechanism as the LPD moves on specific {111} planes upon application of stress at high temperature.

 

Authors with CRIS profile

Malte Lenz Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Christopher Zenk Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Steffen Neumeier Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Erdmann Spiecker Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)

Additional Organisation(s)

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

Related research project(s)

B03 (FP2): Einkristalline y'-gehärtete Co-Basis-Superlegierungen - Legierungsentwicklung, Gitterfehlpassung und mechanische Eigenschaften (SFB/TRR 103) SFB/TRR 103 Jan. 1, 2016 - Dec. 31, 2019

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:

Makineni, S.K., Kumar, A., Lenz, M., Kontis, P., Meiners, T., Zenk, C.,... Gault, B. (2018). On the diffusive phase transformation mechanism assisted by extended dislocations during creep of a single crystal CoNi-based superalloy. Acta Materialia, 362-371. https://dx.doi.org/10.1016/j.actamat.2018.05.074

MLA:

Makineni, Surendra Kumar, et al. "On the diffusive phase transformation mechanism assisted by extended dislocations during creep of a single crystal CoNi-based superalloy." Acta Materialia (2018): 362-371.

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