Cyclic-loading-induced Accumulation of the Geometrically Necessary Dislocations Near the Grain Boundaries of the Ni-Based Superalloy

Abstract

In this study, a nickel-based polycrystalline superalloy is subjected to cyclic loading. The fatigue-induced microstructure is characterized by novel polychromatic X-ray microdiffraction (PXM) together with in-situ neutron diffraction and TEM. In-situ neutron strain measurements reveal two distinct stages of the fatigue damage. Three-dimensional (3D) spatially-resolved PXM micro-Laue measurements demonstrate the development of local texture and formation of geometrically necessary dislocations near the grain boundaries, which is accompanied by lattice rotations and grain subdivisions. The PXM results are in agreement with the in-situ neutron diffraction and TEM results.