This title appears in the Scientific Report :
2015
Please use the identifier:
http://dx.doi.org/10.1016/j.surfcoat.2015.06.048 in citations.
Isothermal aging of a γ′-strengthened Co–Al–W alloy coated with vacuum plasma-sprayed MCrAlY bond coats
Isothermal aging of a γ′-strengthened Co–Al–W alloy coated with vacuum plasma-sprayed MCrAlY bond coats
Cobalt-based superalloys with a γ/γ′ microstructure were discovered in 2006 and are currently being investigated as an alternative to nickel-based superalloys for high-temperature, high-load applications in gas turbine blades. They promise a better castability combined with a similar creep strength....
Saved in:
Personal Name(s): | Terberger, Philipp (Corresponding author) |
---|---|
Sebold, Doris / Webler, Ralf / Ziener, Marco / Neumeier, Steffen / Klein, Leonhard / Virtanen, Sannakaisa / Göken, Mathias / Vassen, Robert | |
Contributing Institute: |
Werkstoffsynthese und Herstellungsverfahren; IEK-1 |
Published in: | Surface and coatings technology, 276 (2015) S. 360 - 367 |
Imprint: |
Amsterdam [u.a.]
Elsevier Science
2015
|
DOI: |
10.1016/j.surfcoat.2015.06.048 |
Document Type: |
Journal Article |
Research Program: |
Helmholtz Interdisciplinary Doctoral Training in Energy and Climate Research (HITEC) Methods and Concepts for Material Development |
Publikationsportal JuSER |
Cobalt-based superalloys with a γ/γ′ microstructure were discovered in 2006 and are currently being investigated as an alternative to nickel-based superalloys for high-temperature, high-load applications in gas turbine blades. They promise a better castability combined with a similar creep strength. Superalloy turbine blades are commonly coated with oxidation resistant bond coats. For this reason their compatibility needs to be studied. Co–9Al–9W specimens with a γ/γ′ microstructure were coated with either a nickel-based or cobalt-based MCrAlY bond coat using vacuum plasma spraying. After aging at 900 °C in air for up to 500 h no decomposition of the γ′ phase was found in the bulk superalloy. The interdiffusion zone shows several different W-rich topologically close-packed phases arising from the dissolution of the γ′ phase in this region. The W-rich phases are identified to be μ phase for both bond coats and R phase for the nickel-based bond coat only. Their total volume is higher for the nickel-based bond coat. Therefore the cobalt-based bond coat is better suited for the Co-based superalloy substrate. Room temperature hardness and Young's modulus were measured using nanoindentation in the initial state and after heat treatment. A significantly higher Young's modulus was found for the cobalt-based bond coat. |