Effect of orientation deviation on random vibration fatigue behavior of nickel based single crystal superalloy

Vibration fatigue refers to the failure of a structure that is repeatedly subjected to loads causing resonance. The vibration fatigue performance of DD6 single crystal superalloy, an anisotropic material, is significantly affected by its various crystal orientations. This study investigates the impact of different vibration signal intensities and orientation deviation angles on the vibration fatigue behavior of DD6 single crystal superalloy. The fracture surface of the specimen that failed due to vibration fatigue was examined using scanning electron microscopy. The findings reveal that the primary failure mode for vibration fatigue of DD6 single crystal superalloy is the dislocation motion on the {111} plane with the greatest resolved shear stress in the octahedral slip system. Moreover, various methods, including time domain and frequency domain methods, were employed to predict the random vibration fatigue life of DD6 single crystal superalloy with different orientation deviation angles. Finally, a New Model was established to consider the vibration signal intensity and crystal orientation deviation angle, which improved the sensitivity of the frequency domain method to the crystal orientation deviation angle under different vibration signal intensities. Compared to other methods, the New Model is more suitable for predicting the random vibration fatigue life of DD6 single crystal superalloy with different orientation deviation angles.