Fig. 1 Optical micrographs of a R, b RA, c ST, d STA, e STD and f STDA samples of Ti-15Mo alloy and comparison materials of g Ti-15Mo-1Fe and h Ti-6Al-4 V alloys. The α-phase in (a) and (b) and the {332} < 113 > twins in (e) and (f) are indicated in the black arrows. The observed plane is the transverse plane, and the horizontal direction is parallel to RD

Fig. 2 a XRD diffraction profiles and b corresponding lattice parameters of the β-phase for different samples of Ti-15Mo alloy and comparison material of Ti-15Mo-1Fe alloy. The transverse plane is analyzed

Fig. 3 a TEM selected area electron diffraction pattern (SAED) and b dark-field (DF) image for STA sample. Bright and dark areas in (b) are isothermal ω-phase and β-matrix, respectively. The zone axis is parallel to [110]β direction

Fig. 4 EBSD analyses and TEM observations for STD sample: a EBSD inverse pole figure (IPF) map, b {332} < 113 > twin boundaries (red lines) combined with image quality (IQ) map, c KAM map, d TEM bright-field (BF) image and e SAED pattern. The transverse plane is analyzed, and the horizontal direction is parallel to RD. The zone axis is parallel to [01 $\stackrel{\mathrm{-}}{1}$]matrix and [01 $\stackrel{\mathrm{-}}{1}$]twin

Fig. 5 Mechanical properties for different samples of Ti-15Mo alloy and comparison materials of Ti-15Mo-1Fe and Ti-6Al-4 V alloys: a Vickers hardness and b Young's modulus. The transverse plane is analyzed

Fig. 6 a Three-point bending loading - unloading curves with a given deflection of 3 mm for different samples of Ti-15Mo alloy and comparison materials of Ti-15Mo-1Fe and Ti-6Al-4 V alloys, and b schematic of given deflection d and residual deflection (D′) in the loading-unloading curve

Fig. 7 Bending properties for different samples of Ti-15Mo alloy and comparison materials of Ti-15Mo-1Fe and Ti-6Al-4 V alloys: a bending yield strength (σpb0.2) and bending strength at a given deflection of 3 mm (σ3mm), and b springback ratio

Fig. 8 Fluorescence images of hFOB 1.19 cells on the surface of a R, b RA, c ST, d STA, e STD and f STDA samples of Ti-15Mo alloy and comparison materials of g Ti-15Mo-1Fe and h Ti-6Al-4 V alloys after 24 h of incubation. The filopodia is indicated in the white arrow

Fig. 9 SEM images of hFOB 1.19 cells on the surface of a R, b RA, c ST, d STA, e STD and f STDA samples of Ti-15Mo alloy and comparison materials of g Ti-15Mo-1Fe and h Ti-6Al-4 V alloys after 24 h of incubation

Fig. 10 a Cell proliferation on different samples of Ti-15Mo alloy and comparison materials of Ti-15Mo-1Fe and Ti-6Al-4 V alloys after 3 days of incubation, and b distribution of P-value between any two different samples

Fig. 11 a Schematic of the effect of strength and modulus on springback ratio, and b relationship among springback ratio, bending strength and Young's modulus for different samples of Ti-15Mo alloy and comparison materials of Ti-15Mo-1Fe and Ti-6Al-4 V alloys

Fig. 12 Correlations of Young's modulus difference (ΔE) with a lattice parameter of the β-phase difference (Δaβ), and b Vickers hardness difference (ΔHv), between two different samples of Ti-15Mo alloy caused by deformation (blue circle) and phase transformation (red circle) microstructures