Manufacturing of Biomedical Ti-Based Alloys with High Oxygen Content and Various Amount of Beta-Stabilizing Elements

摘要

High strength and low elastic modulus are key properties of biomedical Ti-based alloys. Body centred cubic beta phase shows lowest elastic modulus, especially if the stability of the beta phase is low due to the ‘proximity’ to martensitic β to α’’ transformation. It was previously shown that Ti-35Nb-6Ta-7Zr alloy contains biotolerant elements only and exhibits low modulus. By enriching this alloy by 0.7 wt. % of oxygen the strength is significantly enhanced, but elastic modulus increases as well. This fact can be attributed to apparent beta stabilizing effect of oxygen with respect to martensitic β to α’’ transformation. In the present study, six different alloys with reduced niobium and/or tantalum content were prepared by vacuum arc melting. Their microstructure in beta solution treated condition was studied by scanning electron microscopy including energy dispersive spectroscopy and mechanical properties were evaluated by microhardness measurements.