Life assessment of a low-alloy martensitic steel under isothermal low-cycle fatigue-creep and thermo-mechanical fatigue-creep loading conditions

Strain-controlled Low-Cycle Fatigue tests (LCF) and Thermo-Mechanical Fatigue tests (TMF) were performed on a low-alloy martensitic steel in the temperature range between 300 degrees C and 600 degrees C, with and without a strain dwell. TMF tests were performed for three different phase angles between thermal strain and mechanical strain: as in-phase, as out-of-phase and as counter clockwise-diamond. The results show that the phase angle that is employed has a significant influence on the dominant damage mechanism and on the observed lifetime. Finally, a modified damage model is proposed in order to take into account the effect of the phase angle.

Automated summary

The phase angle in TMF tests has a significant influence on the dominant damage mechanism and observed lifetime. A modified damage model has been proposed to account for the effect of the phase angle.