Physical and Mechanical Properties of Ti-Zr-Nb Alloys for Medical Use

The work described in this article is aimed at investigating the properties of a group of Ti-Zr-Nb alloys. In modern orthopedics and traumatology, the use of materials for bone implants with a minimum modulus of elasticity is becoming increasingly important. This is due to a number of advantages that allow for better integration of the implants with the bone tissue, including the reduction in the detrimental effect of the load-shielding effect, a better load distribution, and stress distribution, which allows for increasing the life of the implant. It is known that the lowest modulus of elasticity in titanium alloys at normal temperature is achieved by the phase composition consisting of metastable β-phase. It is possible to achieve the desired structure by a combination of alloy composition selection and heat treatment. Quenching of titanium alloys allows for the high-temperature β-phase to be fixed. This paper provides justification of the choice of compositions of the studied alloys by calculation methods. The structure of alloys after melting in a vacuum electric arc furnace in an argon environment was studied. The ingots obtained had a dendritic structure. Homogenizing annealing in a vacuum furnace at 1000 °C for 4 h was used to equalize the composition. The structure of the alloyed sheets after hot rolling and hot rolling and quenching was investigated. The microstructure of the plates in both variants had uniform grains of polyhedral shape. X-ray phase analysis of the plates showed that the content of metastable β-phase was 100% before and after quenching. Microhardness testing of the plates showed no significant effect of quenching. The result of the mechanical properties study showed an increase in the plasticity of the material after quenching, with the tensile plots of the samples after quenching reflecting the area where the reverse phase transition of β’<-> α’’ occurs. Mechanical studies by cyclic loading showed the presence of a superelasticity effect. The Young’s modulus study gave a result of 51 GPa for one of the compositions studied. The combination of properties of the materials under investigation has the potential for promising use as a basis for bone implants.