Influence of Microstructure and Frequency on Fatigue Crack Growth Rate of Ti_3Al-based Alloy

The effects of microstructure and frequency on fatigue crack growth rate of the Ti-25Al-10Nb-3V-1Mo alloy have been investigated at room temperature.It was found that the fatigue crack growth rate(da/dN) decreased with increasing frequency under the same microstructure.At the corresponding frequency condition,α2+β specimens solutionized at 1080℃ exhibited higher fatigue crack growth resistance than other α2+α and β specimens solutionized at 1110℃ and 1180℃,respectively.The fatigue crack growth resistance for the α2+β specimens solutionized at 1110℃ was the lowest.The volume fraction of primary α2phase was an important factor affecting the fatigue crack growth rate of the alloy.The mechanism of fatigue crack growth of α2+β microstructure is different from that of the β microstructure.