Effect of Solution Temperature on Corrosion Behavior of Ti-6Al-4Zr-3Nb-1.1Mo-1Sn-1V Alloy in Hydrochloric Acid Solution.

Ti-6Al-4Zr-3Nb-1.1Mo-1Sn-1V (Ti90) alloy is widely used in marine engineering and oil and gas extraction due to its excellent strength, impact toughness, and corrosion resistance. The corrosion behavior of Ti90 alloy after solution treatment at 750 °C, 900 °C, 940 °C, and 960 °C in 5 M hydrochloric acid (HCl) solution was investigated using open-circuit potential (OCP), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), static immersion tests, and surface characterization. The results of electrochemical tests indicate that the corrosion resistance of Ti90 alloy increases with rising solid solution temperature. The static immersion tests show that the variation trend of the annual corrosion rate at different solid solution temperatures in 5 M HCl solution is consistent with the electrochemical test results. The corrosion morphology of Ti90 alloy reveals that the α phase is more prone to decomposition than the β phase. The corrosion behavior of Ti90 alloy in 5 M HCl solution is mainly influenced by the volume fraction of the β phase and the size of the α phase.