Aging response of the Ti-35Nb-7Zr-5Ta and Ti-35Nb-7Ta alloys

Titanium alloys are the best metallic biomaterials to be used for implant fabrication. However, the Ti-6Al-4V alloy must be replaced because of V and A] toxicity and, non-toxic beta-stabilizer elements should be used. This work reports the results found after aging treatments of the alloys Ti-35Nb-7Zr-5Ta and Ti-35Nb-7Ta. The alloys were arc melted, homogenized, hot rolled, solubilized and finally aged at several temperatures, from 200 to 700 degrees C for 4h. Afterwards, the alloys were aged at 300 and 400 degrees C for 90h. Characterization was mainly performed by X-ray diffraction, which did not indicate the precipitated phases during the 4 h aging, while it showed that during the 90 It aging the precipitated phases were alpha and omega. The 4 h aging showed that the highest hardness values were found when the alloys were aged at 400 degrees C. The values found were HV (336 +/- 9) for the alloy Ti-35Nb-7Zr-5Ta and HV (317 +/- 13) for the alloy Ti-35Nb-7Ta. It was observed that Zr suppresses omega precipitation but also hinders hardness improvement. (c) 2006 Elsevier B.V. All rights reserved.