Discovery of a 〈2 1 0〉-fiber texture in medical-grade metastable beta titanium wire

The texture and phase evolution of metastable β-III Ti alloy wires, produced in a medical-grade wire-processing facility, are examined via synchrotron X-ray diffraction. The texture development in the β-phase was interpreted by a simple viscoplastic self-consistent (VPSC) modeling approach. Both the stress-induced martensite and stress-induced omega phase transformations are observed during the early stage of cold deformation. The 〈1 1 0〉β texture is gradually replaced by the 〈2 1 0〉β texture at cold work levels above 50% total area reduction or equivalently 0.70 axial true strain. Formation of the 〈2 1 0〉β-fiber from the combined activity of {1 1 2} and {3 3 2} twinning plus conventional slip is observed and may not directly depend upon the stress-induced phase per se. According to the VPSC model, similar texture should occur in other metastable β-Ti alloys subjected to similar wire processing. These data should help inform process-structure-function towards better wire design in titanium-based medical devices.