Effect of hydrogen on the superplasticity of Ti600 alloy

Abstract The influence of hydrogen on microstructure evolution and superplastic behavior of a new near α high-temperature titanium alloy-Ti600 alloy were studied. The results show that hydrogen increases the amount of β phase and δ hydride with fcc structure exists in the specimens when the hydrogen content is over 0.3 wt.%. After hydrogenation, the deformation temperature of Ti600 alloy can be decreased about 80 °C and the strain rate can be increased by at least one order. Addition of proper hydrogen can reduce the flow stress of Ti600 alloy significantly. The flow stress of Ti600–0.5H alloy decreases about 78% of that unhydrogenated Ti600 alloy at 840 °C and 5 × 10 −4  s −1 . Moreover, introducing hydrogen into Ti600 alloy decreases the dislocation density, promotes the dislocation motion and facilitates the β phase flow.