High-strength And Low Modulus Dental Implant Ti-based Alloy

Ti-based alloys are currently considered as the most attractive metallic materials for biomedical applications due to their excellent mechanical properties, corrosion resistance, and biocompatibility. In order to develop new biomedical Ti-based alloys with a low elastic modulus, high strength, excellent corrosion resistance and biocompatibility, porous Ti-based alloys were prepared by power metallurgy using biocompatibleβ-stable elements of Fe and Mo as additional alloy elements. The microstructure, phase composition and mechanical properties of the Ti-xFe alloys, porous Ti-xFe alloys and porous Ti-10Mo-xFe alloys were investigated by optical microscopy, XRD, SEM, EDS, compressive test, tensile test, macro hardness test and microhardness test.The experimental results show that with the increase of Fe addition, hardness of the Ti-xFe increases. Fe has a strengthening effect on Ti-based alloy. After sintering at 1100℃, the compressive strength the Ti-3Fe is 2078MPa, elastic modulus is 11.2GPa, Vickers-hardness is 396MPa, and tensile-strength is 380MPa. The addition of Mo has no obvious effect on the hardness compared with the Ti-xFe alloy, but the microhardness of the Mo rich region is as high as 994 MPa.When 7 wt% NH4HCO3 was added, the highest porosity of the Ti-xFe and Ti-lOMo-xFe alloys was about 23%, and the pores three dimensionally interconnected. The compressive strength of the Ti-xFe and Ti-lOMo-xFe varied in the range of 1141～1577 MPa and 1092-1672 MPa, respectively. Their elastic modulus varied in the range of 7.35～9.33 GPa and 7.89～9.35 GPa, respectively. The compressive strength and elastic modulus of the Ti-3Fe and Ti-10Mo-2Fe alloys are 1577 MPa and1672 MPa, and 8.2 GPa and 9.4 GPa, respectively. The compressive strength and elastic modulus both meet the need of biomedical applications.When Fe and Mo element were added, the corrosion resistance of materials slightly reduced compared with pure Ti. However, they got to a stable state in a short time. They have an excellent corrosion resistance compared with other materials. After dipping in Ringer's solution for 336 h, a layer of oxide protection film was formed on the surface of the Ti, Ti-3Fe and Ti-10Mo-3Fe materials.Cytotoxic test showed that the L929 cell RGR values of the Ti-3%wtFe without NH4HCO3 and Ti-3Fe, Ti-10Mo-3Fe and Ti-10Mo-5 with addition of NH4HCO3 were over % at day 1, day 4 and day 7. The cells grew in good condition on the seventh day. The results indicate that the porous Ti-based materials are not cytotoxic and are good in biocompatibility.