Research Progress on Superplastic Titanium Alloys

Researches on superplasticity of α,α+β,β titanium alloys and titanium matrix composites were summarized in this paper.The influence of grain size and microelement hydrogen on the superplasticity of titanium alloys was also presented.The results indicated that the superplastic property would be improved greatly in titanium alloys with fine grain size,and the superplastic forming temperature decrease more than 100℃,and the strain rate increase 1 to 2 orders of magnitude.Grain sliding controlled by grain boundary diffusion is the main mechanism for low temperature superplastic behavior.The elongation of the titanium alloys with microelement hydrogen was equal to that of the matrix alloys,and their superplastic temperature will also decrease.Applications of some superplastic titanium alloys were also given.At last,the three key research directions were pointed out,which are the study on the superpalsticity of the advanced materials,the superplasticity with low temperature and high strain rate and the superplastic deformation mechanism of the (un-ideal) superplastic materials.