Finding Optimal Thermo-Mechanical Processing for a TNTZ-O Beta-Titanium Alloy

A titanium-based alloy, with niobium, tantalum and zirconium as its main alloying elements, and a small amount of oxygen, was subjected to a thermo-mechanical processing program consisting of hot and cold rolling interspersed with different solution treatments applied above the β-transus temperature. The objective was to analyze the correlation between structure, processing methods and resulting mechanical properties in order to find an appropriate optimized processing path to obtain suitable mechanical characteristics for application in hard tissue implantology. By using microstructural analysis, such as X-ray diffraction and scanning electron microscopy, a series of microstructural features were analyzed. The enthalpy of mixing—ΔHmix—and the atom size difference parameter—δ—were determined, through which the β-solid solution stability was estimated. Tensile tests were performed, through which the main mechanical characteristics were determined: a yield strength (0.2%) and ultimate tensile strength of around 550 MPa and 650 MPa, respectively, with a low Young’s modulus of 56–58 GPa and an improved elongation to fracture value of 17–18%, associated with a good mechanical osteo-compatibility parameter.