Fatigue behavior of GH4169 alloy up to very high cycles

The present paper deals with experimental studies on the long life fatigue behavior of GH4169 alloy. Using the ultrasonic fatigue testing technique, specimens of hourglass shape were fatigue tested in air at room temperature under fully reversed cyclic loading conditions (R=-1). The very high cycle fatigue property of GH4169 alloy was studied and the initiation mechanisms of fatigue cracks were investigated and analyzed with scanning electron microscopy (SEM) and energy dispersive atomic X-ray (EDX). Preliminary results indicate that the S-N curve displays a bilinear decreasing tendency within 10(9) cycles and fatigue failure initiates from inclusions/defects on the specimen surface.