Creep-fatigue interaction behaviors and life predictions for three superalloys

The low-cycle fatigue tests with tensile hold times ranging from 0 to 60 min were conducted for 3 superalloys, HAYNES 188, HAYNES 230 and HASTELLOY X, at 816 degrees C and 927 degrees C under a total strain range control mode to investigate their creep-fatigue interaction behaviors. It was found that under creep-fatigue loading condition, the strain fatigue lives of the three superalloys are dependent on the type of the alloy, duration of strain hold, and test temperature. The different strain fatigue life behaviors exhibited by the three superalloys are related to the difference in the damages from creep and oxidation. In addition, the frequency-modified tensile hysteresis energy modeling was used to correlate the present strain fatigue life data. The result showed that this modeling could give a satisfactory prediction on the creep-fatigue lives of the three superalloys.