Study of Effect of Hold Time on Low Cycle Fatigue Properties of Alloy 617M

Alloy 617 is a candidate material for components operating at elevated temperatures in Advanced Ultra-Supercritical (AUSC) power plants. Low Cycle Fatigue (LCF) and Creep-Fatigue Interaction (CFI) are crucial considerations for high-temperature applications. Strain-controlled fatigue tests were performed on M16 specimens at temperature 650 °C and a strain amplitude of ±0.25%, with hold times of 1 minute and 10 minutes with strain rate of 3x10 -3 s -1 . Cyclic stress response (CSR) was recorded for all tests. The introduction of hold time resulted in decreased cyclic life and lowered CSR. Optical and Scanning electron microscope were utilized for microstructure investigation. Fractography revealed transgranular failure under LCF conditions, while a mixed mode of transgranular and intergranular failure was observed in CFI.