Porosity-related high-cycle fatigue strength of nickel-base single crystals: Fatigue experiments and electron back-scattered diffraction analysis

The fatigue limit of nickel-base single crystal (NBSX) is experimentally studied at an elevated temperature of 980 degrees C. The crack initiation position is revealed as the casting pores in the single crystal under scanning electron microscope (SEM), and distinct fish-eye region is observed on the long cycle fatigue fracture surface. The failure mechanism is explored around the fish-eye by adopting the focused ion beam (FIB) and electron backscatter diffraction (EBSD) technique. The crystalline motion and the fatigue crack initiation mechanism around the initiation pore are revealed by conducting microscopic analyses.

Automated summary

The fatigue limit of nickel-base single crystal (NBSX) at 980 degrees C was experimentally studied. The crack initiation position was found to be casting pores in the single crystal under scanning electron microscope (SEM), and a distinct fish-eye region was observed on the long cycle fatigue fracture surface. The failure mechanism was explored using focused ion beam (FIB) and electron backscatter diffraction (EBSD) techniques.