Effect of hydrogen on corrosion resistance and fatigue properties of near-β Ti-5Al-5Mo-5V-3Cr-1Zr alloy

Clarifying the performance changes and mechanisms under the action of hydrogen is crucial for the safe application of near-β Ti-5Al-5Mo-5V-3Cr-1Zr (Ti-55531) alloy. Effects of hydrogen on the microstructure, corrosion resistance and fatigue properties of near-β Ti-55531 alloy were investigated by controlling electrochemical hydrogen charging time. As the hydrogen content increased by 26.36-fold to 478.20 ppm, the fatigue life decreased by 61.87 % to 6672 cycles, and the passive current density increased by 2.93-fold to 1.06 × 10⁻⁵ A cm⁻² due to the passive film degradation and matrix alterations. Surface microstructure detachment accelerated crack initiation, and plastic damage further contributed to fatigue performance degradation.