Metastable beta type titanium alloys have been attracting attention in various industrial fields because of their special properties such as high specific strength, good formability, high corrosion resistance, and biocompatibility. However, plastic deformation characteristics of the titanium alloys have scarcely been clarified especially under biaxial loading conditions, despite of their importance on metal forming processes. In the present study, uniaxial and biaxial compression tests were performed on titanium-niobium (Ti-Nb) alloys with four different niobium contents, in order to investigate the influences of beta stabilizer content upon compressive deformations. The microstructure of Ti-Nb alloys was found to change from α, α' to p structure with increase of the niobium content. With this change of microstructure, the primary plastic deformation mechanisms were revealed to change from slip and stress-induced martensite to deformation twin and coarse slip with increase of the niobium content and thus the change influenced on the uniaxial and biaxial compressive plastic behaviors.
