IN-VITRO BIOCOMPATIBILITY, MECHANICAL-PROPERTIES, AND CORROSION-RESISTANCE OF TI-ZR-NB-TA-PD AND TI-SN-NB-TA-PD ALLOYS

There is much discussion about the toxic effect of vanadium and aluminum contained in Ti-6Al-4V alloy for prosthetic implants. The goal of the present investigation was to develop new titanium alloys with sufficient mechanical properties using more biocompatible alloying elements: zirconium, tin, niobium, tantalum, and palladium. The relative growth rates of L929 and MC3T3-E1 cells were significantly higher when cultured with the extraction of Ti-10Zr-8Nb-2Ta-0.2Pd or Ti-15Zr-4Nb-2Ta-0.2Pd alloys than when cultured with the extraction of Ti-6Al-4V ELI alloy. The tensile strength, elongation, and reduction of area for Ti-15Sn-4Nb-2Ta-0.2Pd alloy were 989 MPa, 14.4%, and 49.3%, respectively, surpassing Ti-6Al-4V ELI alloy (ASTM F138-84); those for Ti-15Zr-4Nb-2Ta-0.2Pd alloy were 725 MPa, 23.6% and 54.9%, respectively. More than 15% addition of tin as well as zirconium deteriorated the tensile properties. Titanium release into a 5% hydrochloric acid solution from the new titanium alloys was 20-50 mu g/cm(2) per day, though that from Ti-6Al-4V ELI alloy was 1300 mu g/cm(2) per day. The optimum alloy compositions are Ti-15Zr-4Nb-2Ta-0.2Pd and Ti-15Sn-4Nb-2Ta-O0.2Pd, judging from cytocompatibility, corrosion resistance, and mechanical properties. The former is characterized by its high level cytocompatibility and corrosion resistance, while the latter is characterized by mechanical properties. (C) 1995 John Wiley and Sons, Inc.