Water droplet erosion behaviour of Ti-6Al-4V and mechanisms of material damage at the early and advanced stages

In this study, the water droplet erosion (WDE) behaviour of Ti-6Al-4V and mechanisms of material damage were investigated. The WDE test was conducted in an advanced rig in accordance with the ASTM G73 standard. The influence of impact speed between 150 and 350 m/s on the WDE behaviour was explored and the cumulative mass losses versus the exposure time/number of impingements were plotted. It was observed that the higher the impact speed the faster the erosion initiation time and greater the maximum erosion rate (ERmax). ERmax was also found to be related to the impact speed with an exponent of 9.9 in a log-log scale. SEM images showed that the early stages of erosion damage were mainly limited to the formation of microcracks, asperities and isolated pits of irregular shapes. It was found that the most profound mode of material removal during the advanced stage of water droplet erosion was hydraulic penetration. Sub-surface, side wall cracking and material folding/upheaving were also features observed.