A model for life predictions of nickel-base superalloys in high-temperature low cycle fatigueExtensive characterization of low-cycle fatigue damage mechanisms was performed on polycrystalline Rene 80 and IN100 tested in the temperature range from 871 to 1000 C. Low-cycle fatigue life was found to be dominated by propagation of microcracks to a critical size governed by the maximum tensile stress. A model was developed which incorporates a threshold stress for crack extension, a stress-based crack growth expression, and a failure criterion. The mathematical equivalence between this mechanistically based model and the strain-life low-cycle fatigue law was demonstrated using cyclic stress-strain relationships. The model was shown to correlate the high-temperature low-cycle fatigue data of the different nickel-base superalloys considered in this study.
Romanoski, Glenn R. (Massachusetts Inst. of Tech. Cambridge, MA, United States)
Pelloux, Regis M. (MIT Cambridge, MA, United States)
Antolovich, Stephen D. (Georgia Institute of Technology Atlanta, United States)