Preparation and characterization of novel as-cast Ti-Mo-Nb alloys for biomedical applications

Ti and its alloys are the most used metallic biomaterials devices due to their excellent combination of chemical and mechanical properties, biocompatibility, and non-toxicity to the human body. However, the current alloys available still have several issues, such as cytotoxicity of Al and V and high elastic modulus values, compared to human bone. beta-type alloys, compared to alpha-type and (alpha + beta)-type Ti alloys, have lower elastic modulus and higher mechanical strength. Then, new biomedical beta-type alloys are being developed with non-cytotoxic alloying elements, such as Mo and Nb. Therefore, Ti-5Mo-xNb system alloys were prepared by argon arc melting. Chemical composition was evaluated by EDS analysis, and the density measurements were performed by Archimedes' method. The structure and microstructure of the alloys were obtained by X-ray diffraction and optical and scanning electron microscopy. Microhardness values were analyzed, and MTT and crystal violet tests were performed to assess their cytotoxicity. As the Nb concentration increases, the presence of the beta-Ti phase also grows, with the Ti-5Mo-30Nb alloy presenting a single beta-Ti phase. In contrast, the microhardness of the alloys decreases with the addition of Nb, except the Ti-5Mo-10Nb alloy, which has its microhardness increased probably due to the omega phase precipitation. Biological in-vitro tests showed that the alloys are not cytotoxic.

Automated summary

Ti and its alloys are widely used metallic biomaterials due to their excellent properties. However, current alloys have limitations, and new beta-type alloys with non-cytotoxic elements are being developed. This study evaluated Ti-5Mo-xNb alloys and found that increasing Nb concentration led to the growth of the beta-Ti phase, while microhardness decreased except for Ti-5Mo-10Nb alloy. In vitro tests showed no cytotoxicity.