Low Cycle Fatigue Life Evaluation for Cobalt-Based Superalloy FSX-414

Components of gas turbines need to be extremely resistant to elevated temperatures and stresses, corrosion, and erosive environments. The materials used under these environmental conditions are primarily cobalt-based superalloys. In this study, the low cycle fatigue of a cobalt-based superalloy, FSX-414, was examined. The total strain ranges of a gas turbine operating between 760°C and 870°C were considered the parameters representing actual gas turbine operation. In addition, fatigue tests were performed using a trapezoidal waveform to reflect the operation and stop conditions of a gas turbine with frequent shutdowns. The fatigue test results were compared with results obtained using the Manson-Coffin method and the energy method. The fractured surface was analyzed using a scanning electron microscope(SEM).