Greatly improving corrosion resistance of Ti alloy by regulating basketweave microstructure and phase electronic structure

In this paper, the effects of basketweave structure and phase electronic structure regulation on the corrosion resistance of Ti-0.3Mo-0.8Ni alloy were investigated. With the increasement of the V quality fraction in the alloy, the lath length and orientation of α phases gradually become shorter and more. The microstructure transforms from lamellar structure to basketweave structure, which the content of the β phase and the ratio of β/α phase boundary are increased greatly. With the increasement of V quality fraction, the passivate film becomes denser, thicker and more stable, which is because the increasement of the ratio of α/β phase boundary makes the passivate film easier to form. In addition, the XPS results show that the proportion of TiO₂ and metal oxides in the passivate film increases. The corrosion resistance increases with the addition of V content. Especially, the V quality fraction ≥ 4 wt.%, the corrosion resistance is greatly increased. It is because the V changes the electronic structure of the β and α phase, which reduces the density of electronic states near the Fermi level. Secondly, the content of β phase is greatly increased because of the basketweave structure, which also improves the corrosion resistance.