Influence of the different salt deposits on the fatigue behavior of a directionally solidified nickel-based superalloy

• Effect of different salt deposits on the fatigue behavior of DZ125 was investigated.
• HTHC significantly influences the cyclic stress–strain response and fatigue life.
• A competition exists between surface and internal crack initiation.

The influence of hot corrosion on the fatigue behavior of a directionally solidified nickel-based superalloy DZ125 was investigated at 850 °C in air using bare and salt-coated specimens with different amount of salt deposit. Experimental results showed that the fatigue life of salt-coated specimen decreased compared with that of the bare specimen, and this decreasing trend accelerated with increased salt-deposit amount. The hot-corrosion-induced damage to fatigue life was found to be associated with decreased net area and early crack initiation from the surface corrosion layer. Fracture surfaces of the specimens were examined to reveal the characteristics of fatigue-crack initiation.