Fatigue Mechanism in Titanium at Ultrasonic Frequency.
GEORGE WASHINGTON UNIV WASHINGTON D C INST FOR THE STUDY OF FATIGUE FRACTURE AND STRUCTURAL RELIABILITY
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The fatigue mechanism in titanium was studied metallographically for small strain amplitudes approximately 0.003 at the normal engineering test frequency of 1700 cpm and at the ultrasonic frequency of 16000 Hz. It is found that the ultrasonic frequencies develop localized strains at solitary slip bands on the order of the theoretical strength of the material approximately 0.1G. These solitary slip bands develop into micro-cracks which are the source of fatigue initiation at the ultrasonic frequency. The low frequency fatigue in contrast develops from apparently slipless transgranular shear microcracks. Author
- Metallurgy and Metallography