The Influence of Aging Treatment on a Ti-Nb-Ta-Zr-O Alloy Processed by High-Pressure Torsion

In this study, a Ti-29Nb-13Ta-4.6Zr-0.07O (wt.%) (TNTZO) alloy was processed using an alternative method involving severe plastic deformation through high-pressure torsion (HPT), followed by aging heat treatment at 400°C for two different durations: 1.2 ks and 6 ks. The aim was to investigate the influence of HPT processing and aging on microstructural evolution, phase stability, and hardness of the TNTZO alloy. The samples were characterized by optical and scanning electron microscope, X-ray diffraction, Vickers microhardness, and differential scanning calorimetry. A complete stabilization of the β-phase was achieved through the combination of HPT processing and aging treatment, even when employing shorter aging times. Notably, the β-phase exhibits a lower elastic modulus, and an increase in its volume fraction may lead to a reduction in the alloy’s elastic modulus. Additionally, samples subjected to more intense HPT deformation displayed a heightened propensity for the precipitation of secondary phases during aging. A substantial enhancement in microhardness was observed in the samples that underwent HPT deformation followed by aging, with values reaching as high as 400 HV. These improved properties, due to the alternative processing route employed in this study, render this alloy more prone to be used in biomedical applications.