%0 Journal Article
%A Terberger, Philipp
%A Sebold, Doris
%A Webler, Ralf
%A Ziener, Marco
%A Neumeier, Steffen
%A Klein, Leonhard
%A Virtanen, Sannakaisa
%A Göken, Mathias
%A Vassen, Robert
%T Isothermal aging of a γ′-strengthened Co–Al–W alloy coated with vacuum plasma-sprayed MCrAlY bond coats
%J Surface and coatings technology
%V 276
%@ 0257-8972
%C Amsterdam [u.a.]
%I Elsevier Science
%M FZJ-2015-05706
%P 360 - 367
%D 2015
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000360594600045
%R 10.1016/j.surfcoat.2015.06.048
%U https://juser.fz-juelich.de/record/255546