Stress-induced martensitic transformation of metastable β-titanium alloy

The constituent phases and associated deformed microstructure of the quenched Ti–xNb–(0.5–1.5) at.% Si alloy consisting of non-cytotoxicity elements, where x = 24–30 at.%, were investigated to provide pseudoelasticity for biomedical and sensor applications. Optical microscopy revealed that stress-induced martensitic transformation takes place during the deformation in the present alloys. It is confirmed from the X-ray diffraction results of the deformed specimens that the crystal structure of the stress-induced martensite phase is the orthorhombic so-called α″ structure. Within the alloys having β(bcc) phase studied Nb-poor region appeared to exhibit a dominant behavior for stress-induced martensitic transformation than Nb-rich region. This result suggests that metastable β phase is superior to stable β phase for the occurrence of stress-induced martensitic transformation in the present alloy system.