Effect of hydrogen charging on microstructural evolution and corrosion behavior of Ti-4Al-2V-1Mo-1Fe alloy

The effect of hydrogen charging on microstructural evolution and corrosion behavior of a Ti-4Al-2V-1Mo-1Fe alloy in a 3.5 wt.％NaCl solution was investigated. The results showed that the hydrogen charging induced the formation and growth ofγ-TiH andδ-TiH2 phases, leading to the initiation and propagation of hydrogen-induced cracks. It was also found that hydrogen charging can change the passivity of this alloy and increase its pitting corrosion susceptibility. The main reason for these was attributed to the formation of hydrides inαphase in the Ti-4Al-2V-1Mo-1Fe alloy, leading to the preferential dissolution of theαphase and thus the deterioration in the protective ability of passive film.