Effect of Tantalum Content on the Structure and Mechanical and Biochemical Properties of Ti–20Nb–xTa Alloys (x = 7.5, 10.0 at %) for Medical Implants

Abstract—The structure, phase composition, mechanical properties, and biocompatibility of medical Ti–20 at % Nb–7.5 at % Ta and Ti–20 at % Nb–10 at % Ta alloys are studied after warm rolling to a thickness of 1.5 mm and subsequent quenching from 600 and 800°C. The alloys consist mainly of the β phase; the alloy with 7.5 at % Ta also contains traces of the α'/α" phases. Quenching from 600°C reduces the tensile strength of alloys to 526–528 MPa, and quenching from 800°C reduces it to 499–506 MPa. The relative elongation of the rolled alloys is 9.7–9.8%. After quenching from 600 and 800°C, it increases to 13.3–13.5 and 15.5–19.4%, respectively. The tantalum content affects the manifestation of the hyperelasticity effect; for the quenched Ti–20Nb–7.5Ta alloy, the hyperelastic deformation is ~1.5%, and this effect for the Ti–20Nb–10Ta alloy is weakly expressed. Both alloys do not have a toxic effect on human neuroblastoma SH-SY5Y cells. The quenched Ti–20Nb–7.5Ta alloy is the most promising composition for the use in implants.