Isothermal and thermomechanical fatigue behaviour of Ti–6Al–4V titanium alloy

In this study, the overall view of in-house development of thermomechanical fatigue (TMF) test capability has been presented. Using this test facility, mechanical strain controlled in-phase (IP) and out-of-phase (OP) TMF behaviour of Ti–6Al–4V alloy has been investigated in the temperature range 100–400 °C with ramp heating and cooling rate of 2 °C/s. Isothermal low cycle fatigue (IF) tests have also been conducted at 100 °C and 400 °C for comparison with TMF data. The combined effect of development of tensile mean stresses and metallurgical degradation due to oxidation led to detrimental OP-TMF fatigue life as compared to IP-TMF and IF loading.

► The IP and OP-TMF behaviour of Ti–6Al–4V alloy (100–400 ̊C) has been studied.
► The designed hollow specimens showed negligible thermal gradients.
► The alloy showed detrimental OP-TMF life as compared to IP-TMF and IF life.