Low cycle fatigue behavior of a plasma-sprayed coating material

Conference · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6910164

Gayda, J; Gabb, T P; Miner, Jr, R V

Single crystal nickel-base superalloys employed in turbine blade applications are often used with a plasma spray coating for oxidation and hot corrosion resistance. These coatings may also affect fatigue life of the superalloy substrate. As part of a large program to understand the fatigue behavior of coated single crystals, fully reversed, total strain controlled fatigue tests were run on a free standing NiCoCrAlY coating alloy, PWA 276, at 0.1 Hz. Fatigue tests were conducted at 650 C, where the NiCoCrAlY alloy has modest ductility, and at 1050 C, where it is extremely ductile, showing tensile elongation in excess of 100 percent. At the lower test temperature, deformation induced disordering softened the NiCoCrAlY alloy, while at the higher test temperature cyclic hardening was observed which was linked to gradual coarsening of the two phase microstructure. Fatigue life of the NiCoCrAlY alloy was significantly longer at the higher temperature. Further, the life of the NiCoCrAlY alloy exceeds that of coated, /001/-oriented PWA 1480 single crystals at 1050 C, but at 650 C the life of the coated crystal is greater than that of the NiCoCrAlY alloy on a total strain basis.

• Research Organization: National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
• OSTI ID: 6910164
• Report Number(s): N-86-31699; NASA-TM-87318; E-3050; NAS-1.15:87318; CONF-860340-12
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ALUMINIUM ALLOYS
CHROMIUM ALLOYS
COATINGS
COBALT ALLOYS
CRACK PROPAGATION
CRYSTAL STRUCTURE
CRYSTALS
FATIGUE
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
MONOCRYSTALS
NICKEL ALLOYS
NICKEL BASE ALLOYS
SPRAYED COATINGS
TEMPERATURE DEPENDENCE
TURBINE BLADES
YTTRIUM ALLOYS