Propagation of fatigue crack in amorphous Fe40Ni40B20 at high-frequency loading

This work studies the fatigue crack growth in Fe40Ni40B20 metallic glass using the stressing by longitudinal ultrasonic waves of frequency 20.2 kHz. A relation between the rate of fatigue crack propagation and stress intensity factor is derived. An extremely low threshold value of the stress intensity factor, below which a fatigue crack cannot propagate, was found. Fractographic analysis of the fatigue fracture surfaces by scanning electron microscopy confirmed that no so far known mechanism of fatigue failure was present. No slip bands were observed near fatigue fracture surfaces