Synthesis and Characterization of a Ti-Zr-Based Alloy with Ultralow Young's Modulus and Excellent Biocompatibility

Recently, metastable beta-type Ti alloys have attracted attention as promising materials for medical implants due to low Young's modulus and superior biocompatibility. The former is dependent on texture developed during the thermomechanical process. Herein, new Ti-Zr-Nb-Sn-Mo alloys with ultralow Young's modulus and excellent biocompatibility are developed as promising materials for medical implants. The effect of Mo on the microstructure and mechanical properties of the Ti-18Zr-5Nb-3Sn system is investigated. X-ray diffraction (XRD) and scanning electron microscope (SEM) results reveal that Mo acts as a beta-phase stabilizer. Moreover, mechanical behavior and recrystallization texture show strong composition dependence; the 2.5Mo alloy shows the lowest Young's modulus of 40 GPa. This is due to the formation of a recrystallization texture with strong Goss component of . Corrosion behavior of the 2.5Mo alloy in the cell culture medium is similar to that of the commercially pure titanium (cp-Ti), suggesting excellent corrosion resistance in the biological environment. Both murine fibroblasts and osteoblastic cells show good growth on the 2.5Mo alloy as the same level of that on the cp-Ti. Implantation into rat subcutaneous tissue confirms no significant difference in the tissue reaction between the 2.5Mo alloy and the cp-Ti.