Investigation of mechanical properties of Ti alloys developed for bone-tissue engineering applications

In this study, as an alternative to conventional orthopedic implant materials, Ti-Nb-Zr (TNZ) alloys exhibiting superior mechanical performance with nominal compositions of Ti-34Nb-25Zr, Ti-30Nb-32Zr, Ti-28Nb-35.4Zr and Ti-24.8Nb-40.7Zr (wt.%) have been developed. Microstructure, mechanical property (tensile strength, yield strength, compressive yield strength, Young's modulus, elastic energy, toughness, elastic admissible strain and micro-hardness), and cytocompatibility of TNZ alloys were investigated in comparasion to each other. TNZ alloy specimens presenting superior plastic deformation ability during room-temperature compression test did not undergo fracture, and no crack formations occurred. The tensile strength, yield strength, Young's modulus, elongation at rupture, elastic energy and toughness of TNZ alloys were calculated between the values of 704–839 MPa, 682-810 MPa, 62-65 GPa, 9.9-14.8%, 5.02-6.74 MJ/m3 and 60.44-112.85 MJ/m3, respectively. The tensile strength, yield strength, Young's modulus and elongation at rupture value of Ti-34Nb-25Zr alloy, exhibiting the best mechanical performance with the elastic admissible strain value of 1.31%, were calculated as 839.0 ± 31.8 MPa, 810.0 ± 48.0 MPa, 62.0 ± 3.6 GPa and 14.8 ± 1.6 (%), respectively. By conducting cytocompatibilty test, it was confirmed that TNZ alloys have excellent cytocompatibility feature. By taking into consideration all these above mentioned properties, TNZ alloys are candidate for orthopedical implant applications.