Microstructure, mechanical properties, and preliminary biocompatibility evaluation of binary Ti-Zr alloys for dental application

The microstructure, mechanical properties, and in vitro biocompatibility of vacuum-sintered Ti-xZr binary alloys (x = 5, 15, 25, 35, 45 wt%) were investigated. The results indicated that alpha and alpha ' phase existed in Ti-xZr alloys. The hardness of the Ti-Zr alloys increased as the contents increased and ranged from 473 HV (Ti-5Zr) to 525 HV (Ti-45Zr). Increasing Zr content could lead to an increase in compressive and bending strength. Additionally, the Ti-45Zr alloy exhibited the maximum bending strength of 867.1 MPa and the maximum compressive strength of 1599.8 MPa which were much larger than that of CP-Ti. Moreover, all Ti-Zr alloys showed a lower elastic modulus (ranging from 53.5 to 59.3 GPa) compared with CP-Ti (103 GPa). The in vitro cytotoxicity tests were carried out for biocompatibility evaluation. The alloys presented no cytotoxic effects and the surface of the alloys exhibited great growth conditions for MG-63 cells. The Ti-45Zr alloy exhibited better mechanical properties and biocompatibility. In conclusion, Ti-45Zr alloy is of great potential for dental applications.