Fatigue Mechanism in Titanium at Ultrasonic Frequency

Abstract

The fatigue mechanism in titanium is studied metallographically for small strain amplitudes (∼0.003) at a frequency of 1700 cpm and at the ultrasonic frequency of 16 000 cps. The ultrasonic frequencies develop high localized strains at solitary slip bands and these bands become the microcracks initiating fatigue. The low-frequency fatigue in contrast develops from apparently slipless transgranular shear cracks.