抄録
It has been confirmed that sintered Ti-mass%(%)Cr alloy with martensitic structure exhibits superplasticity, at around 1023 K. Mechanical properties of the sintered material can be improved with rising density by superplastic deformation. In this study, superplastic deformation behaviors of Ti-4%Cr-Al ternally alloys were investigated for the purpose of fabricating a sintered Ti alloy with higher strength. Ti4%Cr-6%Al alloy with martensitic structure exhibited superplasticity (about 350% elongation) on condition that the phase ratio a to β is about 1:1. However, the superplastic elongation could not be obtained in the Ti-4%Cr-(2, 4)%Al alloys. It is important for an exhibition of superplasticity in Ti-4%Cr-Al alloys to do alloy design that the phase ratio a to β is about 1:1 at temperature which equiaxization of acicular α grains finishes, and Ti-4%Cr-6%Al is suitable for the compotion. Mechanical properties of densificated Ti-4%Cr-6%Al alloy are in not at all inferior to those of Ti-6Al-4V alloy produced by ingot metallurgy.
