Microstructural-Based Physics of Failure Models to Predict Fatigue Reliability

The fatigue life of materials is strongly influenced by their microstructure. The scatter in fatigue life is caused by the scatter in grain size, grain orientation, and stresses induced in each grain of the material due to external loading. A novel microstructural fatigue crack growth model that accounts for real-life variability in the material is presented in this study. Ti-6Al-4V, a common aerospace titanium alloy used in numerous turbine engines, has been studied to predict its fatigue life and scatter at load ratios of 0.1 and -1.0. The predictions have been compared with experimental data. Results indicate that the microstructural material models accurately predict the behavior of Ti-6Al-4V.