Microstructure investigation of Ti-26Nb alloy manufactured from elemental powders by electron beam melting

Alloys which are planned to be used for implants fabrication must possess excellent biocompatibility, high strength, and low Young's modulus. A low elastic modulus, close to that of the cortical bone could significantly reduce the stress-shielding phenomenon usually occurring after surgery. Beta-titanium alloys such as Ti-Nb are good candidates for this purpose. Nb is known as a biocompatible metal used for titanium β-phase stabilization. Previous investigations indicate that the increase of Nb content results in the increase of β phase amount but the decrease of β grain size. In this study, we were aiming at the investigation of the microstructural properties of a titanium alloy manufactured by electron beam melting from the elemental powders mixture of Ti and Nb with 26 at.% of Nb. The influence of operating parameters on the efficacy of dissolving Nb particles in Ti was studied. The results obtained by SEM analysis demonstrated that electron beam energy has a significant effect on the homogeneity of the manufactured specimens. To obtain homogeneous and porosity-free specimens high energy level is required. The microstructure of these specimens was characterized.