Abstract:Near β-type TLM titanium alloy tubes with small diameter and thin wall were fabricated by a combination of cold rolling and intermidate anneal. The mechanical behaviors related to the phases and microstructures were studied using optical metallography (OM), X-ray diffraction (XRD), scanning electron microscope (SEM) and tensile tests. The results show that the cold-rolled microstrcutre composed of β phase and stress induced martensite (SIMα?) exhibits obvious non-linear elastic deformation behavior, while the annealed single β phase displays the “double-yielding” associated with stress-induced martensitic phase transformation. Present authors consider that the non-linear elasticity has certain dependence on both of SIMα? and complicated sub-structures induced by the cold deformation, but both of which make an unconspicuous contribution to the plasticity. Although the elongation decreases after the cold rolling, the cold rolled microstructure still shows the ductile fracture mode similar with that of annealed specimens, which indicates that wider plasticity range of present TLM alloy supplys a tremendous potential in its deep cold deformation.