Frequency dependence of estimated fatigue limit by lock-in infrared thermography for commercially pure Ti

Abstract

Fatigue limit was estimated by the lock-in infrared thermography for commercially pure titanium (CP-Ti JIS Gr. 2) at room temperature. Fatigue tests were performed at low frequencies of 1 Hz and 4 Hz at stress ratio (R) of-1, and 7 Hz at R=0.05. CP-Ti showed valuable dissipated energy at the low frequencies and frequency dependency of fatigue limit was negligible. In addition, a positive correlation is observed between dissipated energy and strain energy. It meant that the increase of dissipated energy results from the increase of plastic deformation.