Microstructural and mechanical properties of β-type Ti-Mo-Nb biomedical alloys with low elastic modulus

The microstructural and mechanical properties of beta-type Ti74-xMoxNb26 (x = 0, 2, 4, 6, and 8 at.%) biomedical alloys with low elastic modulus were investigated. The experimental results show that the Ti74Nb26 alloy is composed of the beta and alpha '' phases; however, the Ti74-xMoxNb26 (x = 2, 4, 6, and 8 at.%) alloys are composed of only a single beta phase. Based on the stress-strain curve, the Ti66Mo8Nb26 alloy with the large yield strength and elastic energy can consider as biomedical and functional materials. The Mo addition not only stabilizes the beta phase of the alloys, but also increases the strength, and retains the ductility of the Ti74Nb26 alloy. Based on nanoindentation technique, the reduced elastic modulus (E-r) of Ti66Mo8Nb26 alloy with the high hardness (H) is 54.5 GPa, which is 1.5-5.5 times of that of human bone (10-30 GPa), and is the smaller than that of commercial Ti-6Al-4V biomedical alloy (120 GPa). The wear resistance (H/E-r) and anti-wear capability (H-3/E-r(2)) ratios of Ti66Mo8Nb26 alloy are 0.0591 and 0.0112 GPa, respectively, indicating that the good wear resistance and anti-wear capability, or long service life as biomedical materials, compared with those of CP-Ti alloy. In addition, the elastic recovery values of the Ti-Mo-Nb alloys are larger than that of CP-Ti alloy (20.4%), which indicates that the Ti-Mo-Nb alloys exhibit the higher impact resistance. (C) 2019 Elsevier B.V. All rights reserved.