Effects of Deformation and Phase Transformation Microstructures on Springback Behavior and Biocompatibility in β-Type Ti-15Mo Alloy

This study examined the mechanical properties, springback behavior from three-point bending loading–unloading tests and biocompatibility from human osteoblast cell adhesion and proliferation experiments in Ti-15Mo alloy with different microstructures. The springback ratio increased after the appearance of deformation microstructures including {332} < 113 > twins and dislocations, due to the increased bending strength and unchanged Young’s modulus. By contrast, the change in springback ratio was dependent on the competing effect of the simultaneous increase in bending strength and Young’s modulus after phase transformation, namely, the isothermal ω-phase formation. Good cell adhesion and proliferation were observed on the alloy surface, and they were not significantly affected by the deformation twins, dislocations and isothermal ω-phase. The diversity of deformation and phase transformation microstructures made it possible to control the springback behavior effectively while keeping the biocompatibility of the alloy as an implant rod used for spinal fixation devices.