Effects of tensile load hold time on the fatigue and corrosion-fatigue behavior of turbine blade materials

Fatigue-creep tests were carried out on bare and salt-coated of DZ125 superalloys samples at 850 °C. The fatigue lifetime of a corroded alloy was reduced by more than 80% as the hold time was increased to 120 s. However, the influence of hot corrosion on fatigue lifetime became weaker when the dwell time was further increased to 240 s. It was found that hot corrosion influences the lifetime of the alloy by controlling the crack initiation location. The cracks on salt-coated samples were initiated on the corrosion layer. These findings enable an accurate assessment of the hot-corrosion-induced fracture behavior of superalloys.