Thermal-mechanical fatigue behavior and lifetime prediction of P92 steel with different phase angles

The influence of phase angle varying from 0° (in-phase, IP), 90° (clockwise diamond, CD) and 180° (out-of-phase, OP) on thermal-mechanical fatigue behavior and lifetime of P92 steel has been investigated in present paper. Thermal-mechanical fatigue (TMF) tests were conducted under mechanical strain control whose amplitudes were 0.4%, 0.6% and 0.8% with thermal cycles between 550 °C and 650 °C. For comparison, isothermal fatigue (IF) tests also have been achieved at maximum circular temperature of 650 °C under the three mechanical strain amplitudes. Both thermal-mechanical and isothermal fatigue tests were finished with the equal mechanical strain ratio of Rε = −1 and cycle period of 120 s. Results show that the sequence of failure lifetime is NfOP