Investigating fatigue life degradation of TC11 titanium alloy in hot salt corrosion environment

The fatigue life degradation of the TC11 titanium alloy in the hot salt corrosion environment, which is commonly used in aero-engine compressor components, was investigated. Hot salt corrosion fatigue tests were conducted within the temperature and load range of an aero-engine compressor component. The results show that the fatigue life of the TC11 titanium alloy in the hot salt corrosion environment significantly decreases by 1 to 2 orders of magnitude compared with the non-corrosion life at 450 ℃ and that the dispersion was relatively large. The corrosion life of hot salt at different temperatures shows a similar pattern, but with the increase of temperature, the corrosion is more intense, and the fatigue life decreases greatly. The failure mechanism analysis of corrosion fatigue fracture specimens was also conducted. The results show that unlike the traditional non-corrosive mechanical fatigue, which mostly has a single-source crack initiation, the hot salt corrosion fatigue has an obvious multi-source crack initiation under high stress. Finally, the hot salt corrosion fatigue life prediction model of the TC11 titanium alloy based on the damage mechanics method was established, taking into consideration the coupling relationship between mechanical damage and corrosion environment damage. All the prediction results are within the double dispersion band of the test life of the TC11 titanium alloy, indicating that the model can well predict its hot salt corrosion fatigue life.