Hot corrosion damage mechanism of Ti6Al4V alloy in marine environment

Abstract

This study investigated the corrosion behaviors of Ti6Al4V alloy during the hot salt and hot salt - water vapor tests. Ti6Al4V suffered from slight oxygen erosion at the initial stage, while chlorine greatly accelerated the oxide growth. The initial and accelerated oxidation reactions resulted in a continuous mass gain of Ti6Al4V during the hot salt test. Ti6Al4V experienced severe corrosion degradation during the hot salt - water vapor test. The reaction between oxides, chloride salt and water induced the formation of hydrochloric acid (HCl), while chlorine reacted with water to form HCl. The HCl subsequently reacted with the alloy to form gaseous chlorides, that volatilized to the outside and consequently led to a significant mass loss of Ti6Al4V. These results confirmed that the oxidation - hot salt - water vapor synergism effect showed a strong damage on the hot end components of titanium alloy during the marine service.