Elemental partitioning and mechanical properties of Ti- and Ta-containing Co-Al-W-base superalloys studied by atom probe tomography and nanoindentation

Povstugar I, Choi PP, Neumeier S, Bauer A, Zenk C, Göken M, Raabe D (2014)

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2014

Journal

Acta Materialia Elsevier

Publisher: Elsevier

Book Volume: 78

Pages Range: 78-85

DOI: 10.1016/j.actamat.2014.06.020

Abstract

Elemental partitioning and hardness in Ti- and Ta-containing Co-base superalloys, strengthened by γ′-Co(Al, W) precipitates, have been studied by local measurements. Using atom probe tomography, we detect strong partitioning of W (partitioning coefficients from 2.4 to 3.4) and only slight partitioning of Al (partitioning coefficients ≤1.1) to the γ′-Co(Al, W) phase. Al segregates to the γ/γ′ phase boundaries, whereas W is depleted at the γ side of the boundaries after aging at 900 °C and slow air cooling. This kind of Al segregation and W depletion is much less pronounced when water quenching is applied. As a result, these effects are considered to be absent at high temperatures and therefore should not influence the creep properties. Ti and Ta additions are found to strongly partition to the γ′ phase and greatly increase the γ′ volume fraction. Our results indicate that the alloying elements Al, W, Ti and Ta all occupy the B sublattice of the A B structure (L1 type) and affect the partitioning behavior of each other. Nanoindentation measurements show that Ta also increases the hardness of the γ′ phase, while the hardness of the γ channels remains nearly constant in all alloys. The change in hardness of the γ′ phase can be ascribed to the substitution of Al and W atoms by Ti and/or Ta. © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Authors with CRIS profile

Steffen Neumeier Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Alexander Bauer Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Christopher Zenk 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

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

How to cite

APA:

Povstugar, I., Choi, P.-P., Neumeier, S., Bauer, A., Zenk, C., Göken, M., & Raabe, D. (2014). Elemental partitioning and mechanical properties of Ti- and Ta-containing Co-Al-W-base superalloys studied by atom probe tomography and nanoindentation. Acta Materialia, 78, 78-85. https://dx.doi.org/10.1016/j.actamat.2014.06.020

MLA:

Povstugar, Ivan, et al. "Elemental partitioning and mechanical properties of Ti- and Ta-containing Co-Al-W-base superalloys studied by atom probe tomography and nanoindentation." Acta Materialia 78 (2014): 78-85.

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