Abstract:

A model is proposed for the fatigue life estimation of the material with consideration of microstructure, stress concentration and cyclic load ratio. In the fatigue life estimation, the factors, such as grain size, stress concentration and cyclic load ratio are taken into account in the parameter representing the fatigue limit. In order to fill the model, it is sufficient to have results from monotonic tensile testing and characteristics of microstructure of the initial material. The model is tested using the fatigue testing results for specimens of Ti–6Al–4V titanium alloy condensate prepared by electron-beam physical vapor deposition method (EB PVD-method). The specimens had manufacturing defects, such as column defects of different diameters reaching the specimen surface. The model is also tested using the experimental fatigue data for the Ti–6Al–4V titanium alloy taken from the literature for various cyclic load ratios. Comparison between results of calculation and experiment showed a good agreement. The approach proposed can be used for the rapid assessment of fatigue resistance characteristics in new materials development, and also for the remaining life evaluation of structures with no costly and long-term fatigue and fatigue crack growth resistance tests

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