Nanomechanical properties of surface-modified titanium alloys for biomedical applications

The mechanical properties of the oxide layers developed at elevated temperature on three vanadium-free titanium alloys of interest for biomedical applications were investigated by means of the nanoindentation technique. The as-received alloys (Ti–13Nb–13Zr, Ti–15Zr–4Nb and Ti–7Nb–6Al) and their oxide scales formed by reaction with air at 750 °C for several oxidation times were analysed comparatively. In particular, the hardness and the Young’s modulus exhibit larger values for the thermally oxidized alloys than for the untreated specimens. However, the Ti–7Nb–6Al alloy shows a different tendency to that of the TiNbZr alloys, which seems to be related to a different oxide layer growth as a function of the oxidation time.This work was partially supported by the Spanish “Programa de Tecnología de los Materiales de la Comunidad Autónoma de Madrid” under Projects 07N-0050-1999 and 07N-0066-2002, and by the Spanish MEC under Projects MAT-2006-13348, MAT2007-66719-C03-03, MAT2007-62732 and “Nanoselect” of the Spanish Consolider-Ingenio 2007 program.Peer reviewe