Investigations on surface-integrity and mechanical properties of biocompatible grade Ti-6Al-7Nb alloy

In this work, the effect of High-Speed Milling (HSM) on Average Surface Roughness (Ra), Maximum Profile Height (Rz), Hardness (H), Young's Modulus (E) and microstructure have been investigated. HSM with the range of 125–226 m/min is employed to reveal its impact on the machinability of Ti-6Al-7Nb alloy for biomedical application. Effects of Cutting Speed(vc), Feed per Tooth (fz) and Cutting Depth (ap) on 'Ra', 'Rz', 'H' and 'E' were examined under diverse milling conditions. Inferences made from the experimental studies reveal that Ra of 0.3 µm can be obtained from the chosen machining variables: vc = 226 m/min, ap = 80 µm and fz = 0.03 µm/tooth. The corresponding 'H' and 'E' values were found to be 2.3 and 18.1 GPa respectively. Microstructural analysis indicates that grooves formation and chip redeposition are the governing factors for 'Ra'. The experimental results signify that the HSM with high 'vc' leads to the increase of 'H' and reduction of 'E' values thereby enhancing the biocompatibility of Ti-6Al-7Nb alloy.