Experimental Investigation of Crack Initiation in Face-Centered Cubic Materials in the High and Very High Cycle Fatigue Regime

The investigation focuses on the fatigue mechanisms and crack initiation of nickel, aluminum, and copper in the Very High Cycle Fatigue regime, utilizing a custom-built resonant fatigue setup. The study reveals that the resonant frequency of samples changes with increasing cycle numbers, indicating fatigue damage. Notable mechanisms observed include slip band formation, cyclic hardening, and the formation of vacancies and oxidation, which are identified as early indicators of fatigue.