The conventional polycrystalline nickel based superalloys for gas turbine blade application are gradually replaced by the newer and more advanced directionally solidified (DS) superalloys due to their improved mechanical properties. In spite of this development, cheaper aluminide coatings are still widely used on the DS superalloys to protect them from high temperature oxidation and corrosion attack. This paper discusses the modes of service induced degradation such as oxidation, thermal fatigue (TF) and interdiffusion in a DS nickel based superalloy with a diffusion aluminide coating which is currently being used in the high pressure turbine (HPT) of an advanced aero engine. The presence of complex internal cooling passages in the blade along with poor TF properties of the aluminide coating give rise to the initiation of a large number of cracks in the coating. Ingress of oxidants through these cracks leads to the failure of the component.
Degradation of aluminide coated directionally solidified superalloy turbine blades in an aero gas turbine engine
Zerfall von gerichtet erstarrten, aluminid-beschichteten Turbinenschaufeln aus einer Superlegierung
1988
10 Seiten, 12 Bilder, 1 Tabelle, 7 Quellen
Aufsatz (Konferenz)
Englisch
HOCHDRUCK (MECHANIK) , DIFFUSION , RASTERELEKTRONENMIKROSKOPIE , ROENTGENANALYSE , OXIDATION , KORROSIONSPRODUKT , ALUMINID , SUPERLEGIERUNG , NICKELLEGIERUNG , GUSSLEGIERUNG , CHEMISCHE ZUSAMMENSETZUNG , GASTURBINE , TURBINENSCHAUFEL , GERICHTETE ERSTARRUNG , BESCHICHTUNG (UEBERZUG) , THERMISCHE ERMUEDUNG , WERKSTOFFGEFUEGE , GAMMA-PHASE , OBERFLAECHENRISS , OXID , GRENZSCHICHT-FEST-FEST , SIGMA-PHASE , INTERMETALLISCHE VERBINDUNG
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