Enhancing the high-temperature strength of a Co-base superalloy by optimizing the γ/γ' microstructure
Hausmann D, Solís C, Freund L, Volz N, Heinemann A, Göken M, Gilles R, Neumeier S (2020)
Publication Type: Journal article
Publication year: 2020
Journal
Book Volume: 10
Article Number: 321
Journal Issue: 3
DOI: 10.3390/met10030321
Abstract
Compositionally complex polycrystalline γ/γ' CoNi-base superalloys, such as CoWAlloy2 (Co41-Ni32-Cr12-Al9-W5-Ti0.3-Ta0.2-Si0.4-Hf0.1-C-B-Zr) are interesting candidates for new high-temperature materials. To maximize their high-temperature strength, the γ/γ' microstructure has to be optimized by adjusting the multi-step heat treatments. Various microstructures after different heat treatments were analyzed by scanning and transmission electron microscopy and especially in-situ small-angle neutron scattering during heat treatment experiments. The corresponding mechanical properties were determined by compression tests and hardness measurements. From this, an optimum γ' precipitate size was determined that is adjusted mainly in the first precipitation heat treatment step. This is discussed on the basis of the theory of shearing of γ' precipitates by weak and strong pair-couplings of dislocations. A second age hardening step leads to a further increase in the γ' volume fraction above 70% and the formation of tertiary γ' precipitates in the γ channels, resulting in an increased hardness and yield strength. A comparison between two different three-step heat treatments revealed an increase in strength of 75 MPa for the optimized heat treatment.
Authors with CRIS profile
Daniel Hausmann
Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)
Lisa Freund
Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)
Nicklas Volz
Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)
Mathias Göken
Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)
Steffen Neumeier
Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)
Additional Organisation(s)
Related research project(s)
Involved external institutions
Germany (DE)How to cite
APA:
Hausmann, D., Solís, C., Freund, L., Volz, N., Heinemann, A., Göken, M.,... Neumeier, S. (2020). Enhancing the high-temperature strength of a Co-base superalloy by optimizing the γ/γ' microstructure. Metals, 10(3). https://dx.doi.org/10.3390/met10030321
MLA:
Hausmann, Daniel, et al. "Enhancing the high-temperature strength of a Co-base superalloy by optimizing the γ/γ' microstructure." Metals 10.3 (2020).
BibTeX: Download