Fatigue and Fracture Behaviors of Nickel-Based Forging GH4169 Superalloy and Optimization of Model Parameters

AbstractThe aim of this paper was to identify the high-temperature low-cycle fatigue (HTLCF) performances and optimize model parameters of nickel-based GH4169 superalloy. Microanalysis revealed that fatigue lives of specimens obtained from different regions of inhomogeneous radical forging disc were determined by their microstructures, such as the uniformity ratio of grain size and the distribution of δ phase along the grain boundary. Typical fatigue characteristics of all specimens were investigated after HTLCF tests through the analysis on fracture morphologies and secondary cracks. Then, an evolution and optimization process of model parameters in ɛ-N curves was proposed