Matrix Channel Width Evolution of Single Crystal Superalloy Under Creep and Thermal Mechanical Fatigue

Abstract

In this study, experiment and probabilistic modeling of matrix channel (MC) width evolution for single crystal (SC) superalloy is conducted under creep and thermal mechanical fatigue (TMF) conditions. Firstly, fractured and interrupted tests are carried out on SC superalloy, and an image processing program is developed to identify and measure the MC width. Test results show that the rafting rate is greater as the stress, temperature levels or phase difference is larger. Besides, the MC width obeys lognormal distribution, and the standard deviation of MC width follows linear relationship with mean value. In modeling part, a static model is established to predict the mean value evolution of MC width under creep condition. To be generalized to TMF condition, the model is modified to consider non-quasi-static effect. Further, probabilistic model is derived to predict the probability density distribution of MC width. The predictions are in good agreement with the experimental results.