Low cycle fatigue of a polycrystalline Ni-based superalloy: Deformation substructure analysis

The deformation behavior of the polycrystalline superalloy R104 has been characterized via scanning transmission electron microscopy (STEM). Specimens tested under low cycle fatigue (LCF) conditions were examined based on testing temperature, total strain range, and/or cycle number. Extensive electron microscopy characterization has revealed non-planar deformation to be a dominant mode in polycrystalline R104, resulting from ample cross-slipping processes between {1 1 1} and {1 0 0} planes. Somewhat unexpectedly, this mechanism appears at both low and high temperatures, although the macroscopic material response is quite different.