Preparation and characterization of a titanium alloy with the addition of tantalum and zirconium for biomedical applications

Titanium alloys are widely used in the biomedical field due to its excellent corrosion resistance in bodily fluids, high mechanical strength/density ratio, low elastic modulus and good biocompatibility. The most promising alloys to be used in the biomedical field have solid solution elements that decrease the phase transformation temperature of titanium. Such elements are called beta-stabilizers and are obtained as a result of their introduction in the alloy, the decrease of the elastic modulus and an excellent corrosion resistance. Tantalum and zirconium elements, when added to the titanium, improve the corrosion resistance and diminish the elastic modulus, because tantalum is considered a beta-stabilizer element and the zirconium acts as a stabilizing element of this phase, in presence of another beta-stabilizer element. In this paper, Ti-25Ta-5Zr alloy was prepared by arc-melting, aiming biomedical applications. The chemical, structural, microstructural and mechanical characterizations were performed by means of chemical composition measurements, gas analysis, energy dispersive spectrometry (EDS), X-ray diffraction, optical and scanning electron microscopies, Vickers microhardness and elastic modulus. The obtained results showed a good stoichiometry and homogeneity of the samples. Structural and microstructural analyses corroborated each other and indicated that the alloy has the coexistence of two phases, alpha '' (with orthorhombic crystalline structure) and beta (with body-centered cubic structure). The microhardness increased with the addition of such elements and the elastic modulus has values below the commercially used alloys, satisfactory for application as orthopedic implant.