Details

Autor(en) / Beteiligte

• Mendis, B.G.
• Tryon, B.
• Pollock, T.M.
• Hemker, K.J.

Titel

Microstructural observations of as-prepared and thermal cycled NiCoCrAlY bond coats

Ist Teil von

• Surface & coatings technology, 2006-12, Vol.201 (7), p.3918-3925

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2006

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Microstructures of as-prepared and 1100 °C/100 h isothermally annealed NiCoCrAlY bond coat specimens as well as a bond coat obtained from an end of life turbine blade were characterized with TEM. In all specimens the γ grains were observed to consist of fine γ′ precipitates, which form during cooling and are unstable at the higher operating temperatures. The β grains present in the as-prepared specimens were observed to transform to L1 0 martensite in the 1100 °C/100 h isothermally annealed specimen. As a result of substrate-bond coat interdiffusion the M s temperature increases during thermal cycling due to an increase in Ni and decrease in the Cr concentrations of the β-phase. The turbine blade bond coat was also found to contain Cr and Co-rich σ-phase precipitates.