Abstract: The effects of various hydrogen contents on the flow stress(σ),strain rate sensitivity expo- nent(m)and the tensile elongation(δ)of Ti-6Al-4V alloy were studied.The microstructure of the alloy was also investigated.The results indicate that,a suitable amount of hydrogen in the alloy can reduce the flow stress in the temperature range 800—860℃. Consequently,the superplastic temperature can be decreased and the ductility improved.

Key words: Hydrogen, Ti-6Al-4V alloy, strain rate sensitivity exponent, high temperature ductility