Fig. 1. (a) The molar Gibbs free energies of α and β phases and (b) the anisotropy function of f(θ) in the polar coordinate system.

Fig. 2. Morphology of α sideplates with branching at τ=7 × 104 under 1023 K (a-c), 1073 K (d-f) and 1123 K (g-i) respectively. (a, d, g) represent the morphology of α sideplates, (b, e, h) and (c, f, i) represent the distributions of Al and V respectively.

Fig. 3. Growth process of α branching from τ=1 × 104-7 × 104 under 1023 K. The pictures correspond to the position of the rectangular box in Fig. 2(a).

Fig. 4. SEM images of α colony in Ti-6Al-2Sn-4Zr-6Mo (a) and Ti-6Al-4V (b-d) alloys. The insets in (b) show the corresponding orientation map of α colony. (e) The schematics of the growth mechanism of α sideplates with branching in one α colony.