A STUDY ON GH169 CRACK PROPAGATION UNDER CREEP-FATIGUE INTERACTION

As a new technique of crack detection at high temperatures, Reversing DC Electric Potential Method is used to study the crack propagation behaviours of aeroengine turbine disk material GH169 under creep-fatigue interaction at 650 C and at different hold-times. The fracture surfaces has examined with a scanning electron microscope. The experimental results indicate that the life prediction model by hyperbolic sine function is superior to the life prediction model by Paris formulation in correlativity with experimental data and predictability at the crack initiation propagation. Moreover, the former model is more convenient in application. It has been found that the crack propagation ratio obtained in the case of gradually increasing loading is smaller than that resulted from one-time loading.