Reviews on Very High Cycle Fatigue Behaviors of Structural Metals

The paper presents an overview of the present state of study on the fatigue behaviors at very high number of cycles ( $N_f$ > $10^7$ ). A classification of materials with typical S-N curves and influencing factors such as notches, residual stresses, temperatures, corrosion environments and stress ratios are given. The microstructural inhomogeneities of materials and micro-cracks played an important roles in very high cycle fatigue behaviors. The failure mechanisms for the fatigue design of materials and components are mentioned.