An Analysis of Grain Size and Yield Stress Effects on Stress at Fatigue Limit and Threshold Stress Intensity Factor

Abstract

Fatigue limits of smooth specimens and threshold stress instensity factors of specimens with large cracks depend on the microstructure of the material. A simple model in which it is assumed that the plastic zone size near the crack tip is of the order of the grain size at the threshold region has been presented in this analysis which explains the dependence of stress at the fatigue limit and the threshold stress intensity factor on yield stress and grain size.