The effect of temperature on TMF(HCF) crack initiation endurance

•For Tmax in the range 400–480 °C, superimposed HCF loading cycles with strain amplitudes up to a threshold value of ∼±0.03% appear to have no significant influence on out-of-phase TMF crack initiation endurances for vermicular GJV-450 cast irons.•In the same Tmax range, superimposed HCF loading cycles with higher strain amplitudes become increasingly influential, with increasing temperature, over an increasing Δε range of effectiveness.•The extent of influence of superimposed HCF loading on OP-TMF crack initiation endurance is related to an increase in the effect of oxidation on crack development with increasing temperature.