Fatigue crack growth behavior of diffusion-bonded heterogeneous titanium alloy laminate

The fatigue crack propagation behavior of diffusion-bonded heterogeneous TA2/Ti55/TA2 laminate was investigated. Face centered cubic delta phase precipitates in TA2 during diffusion bonding process. The adjacent delta grains have a common {1 1 0} pole. The common orientation relationship between alpha and delta grains is {1120}HCP// {1 1 0}FCC. Strength improvement and secondary cracks due to delta phase play key roles to reduce fatigue crack growth rate in TA2. The fatigue crack growth rate decreases sharply in Ti55 interlayer owing to its high strength and abundant alpha/beta interfaces.

Automated summary

The fatigue crack propagation behavior of diffusion-bonded heterogeneous TA2/Ti55/TA2 laminate was studied. Delta phase precipitates were formed in TA2 during diffusion bonding process. Adjacent delta grains exhibited a common {1 1 0} pole. The common orientation relationship between alpha and delta grains is {1120}HCP// {1 1 0}FCC. The presence of delta phase and secondary cracks contributed to the reduction of fatigue crack growth rate in TA2. The high strength and abundant alpha/beta interfaces in the Ti55 interlayer led to a significant decrease in fatigue crack growth rate.