Effect of the Cobalt Content and Chromium Alloying on the Structure of the Scale Formed on Structural β-NiAl + γ'-Ni3Al + γ-Ni Alloys (Ni–Al–Co System) at 1300°C
- Authors: Drozdov A.A.1,2, Povarova K.B.1, Bazyleva O.A.3, Morozov A.E.1, Antonova A.V.1, Arginbaeva E.G.3, Bulakhtina M.A.1, Ashmarin A.A.1
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Affiliations:
- Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences
- Bardin Central Research Institute of Ferrous Metallurgy
- All-Russia Institute of Aviation Materials
- Issue: Vol 2018, No 11 (2018)
- Pages: 1074-1080
- Section: Article
- URL: https://journals.rcsi.science/0036-0295/article/view/172722
- DOI: https://doi.org/10.1134/S0036029518110058
- ID: 172722
Cite item
Abstract
The structures of the scale and the subscale layers that form during the air oxidation of the β + γ' + γ alloys of the Ni–Al–Co system containing (at %) ~27 Al (alloys 1–3), 10 Co (base alloy 1), 16 Co (alloy 2), and 10 Co and 4.25 Cr (alloy 3) at 1300°C for 100 h are studied. The formation of scale (Al2O3) in all alloys leads to the aluminum depletion of the subscale layers and to the γ' → γ + γ' transition due to the interdiffusion of aluminum and oxygen. An increase in the cobalt content from 5 to 10 at % increases the heat resistance. The degradation of the heat resistance induced by an increase in the cobalt content to 16 at % is related to an increase in the volume fraction of the γ phase in an alloy as compared to the base alloy with 10 at %. The introduction of small amounts of chromium degrades the heat resistance because of the development of internal oxidation, i.e., the penetration of alumina into an alloy along interdendritic γ-phase precipitates. The heat resistance of the chromium-free β + γ' + γ alloy with 10 at % Co at 1300°C, which was estimated from the sample mass increment per unit surface area in 100 h, is higher than the heat resistance of the well-known γ' + γ VKNA and VIN alloys at 1100–1200°C.
Keywords
About the authors
A. A. Drozdov
Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences; Bardin Central Research Institute of Ferrous Metallurgy
Author for correspondence.
Email: aadrozdov76@mail.ru
Russian Federation, Moscow, 119334; Moscow, 105005
K. B. Povarova
Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences
Email: aadrozdov76@mail.ru
Russian Federation, Moscow, 119334
O. A. Bazyleva
All-Russia Institute of Aviation Materials
Email: aadrozdov76@mail.ru
Russian Federation, Moscow, 103767
A. E. Morozov
Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences
Email: aadrozdov76@mail.ru
Russian Federation, Moscow, 119334
A. V. Antonova
Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences
Email: aadrozdov76@mail.ru
Russian Federation, Moscow, 119334
E. G. Arginbaeva
All-Russia Institute of Aviation Materials
Email: aadrozdov76@mail.ru
Russian Federation, Moscow, 103767
M. A. Bulakhtina
Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences
Email: aadrozdov76@mail.ru
Russian Federation, Moscow, 119334
A. A. Ashmarin
Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences
Email: aadrozdov76@mail.ru
Russian Federation, Moscow, 119334