Variability in Fatigue Life of Near-α Titanium Alloy IMI 834

Most aero-engine components and structures are subjected to life critical fatigue loads during service. Near-α titanium alloy IMI 834 is one candidate aero-engine material that is used as high-pressure compressor discs due to its superior fatigue strength and creep resistance. The effect of heat treatment on the microstructure and high-cycle fatigue behaviour of the material has been studied and reported here. The alloy was solution-heat-treated at 1060 °C and subsequently quenched in different media. A strong effect of quench media (cooling rate) on high-cycle fatigue life has been observed. Fractographic investigations were performed to correlate the fracture micro-mechanism with heat treatment. Further, a generalized stress-life model has been deduced from the fatigue data and integrated with finite element analysis to develop a fatigue model for the alloy.