Senior research engineer, Sverdrup Technology, Inc., NASA Lewis Research Center Group, Cleveland, OH
Senior scientific technologist, NASA Lewis Research Center, Cleveland, OH
Pages: 18 Published: Jan 1993
Post failure fractographic and metallographic studies were conducted on Haynes 188 specimens fatigued under bithermal and thermomechanical loading conditions between 316 and 760°C. Bithermal fatigue specimens examined included those tested under high strain rate in-phase and out-of-phase, tensile creep in-phase, and compressive creep out-of-phase loading conditions. Specimens tested under in-phase and out-of-phase thermomechanical fatigue were also examined. The nature of the failure mode (transgranular versus intergranular), the topography of the fracture surface, and the roles of oxidation and metallurgical changes were investigated for each type of bithermal and thermomechanical fatigue test.
damage mechanisms, bithermal fatigue, thermomechanical fatigue, fractography, metallography, oxidation, cobalt-base superalloy
Paper ID: STP24253S