Effect of hot corrosion on cycle deformation and fracture behavior of Ti-6Al-4V alloy under salt coating

The effect of NaCl deposition on the deformation and fracture behavior during the cycle loading of dwell fatigue of Ti-6Al-4V alloy at 500 °C was investigated. Experimental results show that the hot corrosion reduces the dwell fatigue life of the alloy by up to 79 % compared with the bare (without salt) sample, and the degree of hot corrosion damage increase with the decrease of dwell stress. Comprehensive microstructural analysis suggests that the reduction of dwell fatigue life of the salt-coated sample is related to the crack initiation from surface corrosion pits/spalling pits and rapid crack propagation. Moreover, hot corrosion and creep damage are considered to exist competitive relationship during the failure process.