High temperature low cycle fatigue behavior of titanium aluminide Ti–24Al–15Nb–1Mo alloy

The low cycle fatigue behavior of a Ti–24Al–15Nb–1Mo alloy with primary α2 phase, platelet O phase and transformed β triplex microstructure has been studied. The results show the as studied alloy exhibits weak cyclic hardening during strain controlled low cycle fatigue test at 650 °C. The low cycle fatigue behavior of Ti–24Al–15Nb–1Mo alloy obeys the Manson–Coffin behavior. The fatigue life is governed by elastic strain deformation under the present test condition. The fatigue cracks initiate from the primary α2 phase, or the interface of the primary α2 and transformed β matrix. The platelet O phase is the barrier to crack propagation by deflecting the microcrack under cyclic loading. The initiation and linkage of microcracks are the important features in governing fatigue crack growth.