Chemistry Effects in Corrosion Fatigue

In principle, there could be as many different types of corrosion-fatigue behavior as there are metal/environment combinations, since each will interact chemically and electrochemically in different ways. Pessimism in the face of such potential complexity would be justified if we could not, from our knowledge of the corrosion properties of the material in its environment, make worthwhile generalizations. The object of this paper is to identify those common threads running through the experimental observations that enable us to deduce which are the important chemical and electrochemical interactions with the environment influencing the fatigue strength, cyclic endurance, or fatigue crack propagation kinetics of a given material or class of materials. Interpretation of the effects of chemical and electrochemical variables is seen to be dependent on both our basic knowledge of surface corrosion and crevice corrosion phenomena and our perception of the relative importance of the crack initiation and propagation phases of corrosion-fatigue failure in particular materials and test specimen geometries.