Characterization and modeling of the fatigue behavior of 304L stainless steel using the MultiStage Fatigue (MSF) Model

Experimental and microstructural analyses were used to calibrate a MultiStage Fatigue model that included the number of cycles for incubation, microstructurally small crack growth, and long crack growth of 304L stainless steel. Fully reversed cyclic loading tests at strains of 0.3%, 0.5%, and 1.0% were used to characterize the material performance of 304L stainless steel. To assess the microstructural characteristics of 304L stainless steel, the fatigued fracture surfaces were examined with scanning electron microscopy for particles and crack initiation sites, while phases, grain sizes, and grain orientations were investigated using electron backscatter diffraction. Results from both the experimental data and microstructural analysis were then incorporated into the MultiStage Fatigue model to quantify the incubation, small crack regimes, and the total fatigue life of 304L stainless steel. The Multistage Fatigue model captured the fatigue behavior of 304L stainless steel by predicting that fatigue life would be dominated by incubation below 0.5% strain amplitude and by crack growth above 0.5% strain amplitude.