Cavitation erosion-corrosion behavior of Co-6Ti-11V-9Cr superalloy in 3.5% NaCl solution

The corrosion and cavitation erosion (CE) behavior of Co-6Ti-11V-9Cr alloy are investigated in both deionized water and 3.5 wt.% NaCl solution. Utilizing electrochemical methods and CE testing, the research aims to clarify the synergistic effects of CE and corrosion. The results demonstrate that after 8 h of CE exposure, Co-6Ti-11V-9Cr alloy experienced a cumulative mass loss of 1.84 mg in deionized water and 3.42 mg in NaCl solution, leading to mass loss rates of 0.23 and 0.43 mg/h, respectively. In NaCl solution, CE was responsible for 53.8% of the overall damage, with the remaining damage attributed to the combined influences of corrosion and CE. Under CE conditions, both the corrosion potential and corrosion current density of the alloy increased, which accelerated the corrosion process and exacerbated cavitation damage. The material sustained more severe damage in 3.5 wt.% NaCl solution over the same cavitation durations. Ultimately, CE damage mechanism of Co-6Ti-11V-9Cr superalloy was elucidated based on relevant experimental observations.