W. J. Porter, K. Li, University of Dayton Research Institute, Dayton, OH; S. K. Jha, Universal Technology Corporation, Dayton, OH; M. J. Caton, J. M. Larsen, Air Force Research Laboratory, Wright-Patterson AFB, OH
An effort to understand the variability in fatigue behavior based upon location-to-location differences in the microstructure within two IN-100 pancake forgings is described. The microstructures used in this study come from two forgings, one heat treated to a subsolvus condition and the other to a supersolvus condition. In this investigation, fatigue specimens were extracted from inner-, mid-, and outer-radial positions of each forging. Multiple specimens from each location were tested under similar fatigue conditions (temperature, stress and frequency) to assess differences in performance. Detailed fractography was performed on all specimens to identify the type and location of fatigue initiation sites. Additionally, a location-based comparison of the distribution of microstructural features including grain size and gamma prime size was undertaken to illuminate their role in fatigue behavior. Finally, a comparison of the findings for each forging is made and their similarities and differences are discussed.
Summary: The influence of microstructure on variable fatigue behavior in the nickel-base superalloy IN100 is investigated. The fatigue specimens in the study represent two heat treatments and three radial positions from disk-shaped forgings.
