High temperature in-situ SEM observation and crystal plasticity simulation on fretting fatigue of Ni-based single crystal superalloys

The fretting fatigue behavior of Ni-based single crystal (NBSX) superalloy specimens with different crystal orientations ([110] and [010]) was investigated by in-situ scanning electron microscopy at 400 degrees C. The slip lines on the surface of the specimens were captured during the test, and crack paths were recorded. These results show that the dominant deformation mode of fretting fatigue at 400 degrees C is the crystallographic slip. Fretting contact conditions were simulated by the crystal plasticity finite element (CPFE) method. It was found that the activated slip systems and planes in the numerical results are correlated to crystal orientations. The predicted slip lines corresponding to the dominant slip planes obtained by the simulations are in good agreement with the experimental observations. And the crack initiation sites in the experiment coincide with the equivalent plastic strain in the simulation.