Corrosion Fatigue

Fatigue, in general, is the loss in strength of structural materials caused by cyclic loads [1]. A possible dangerous outcome is fatigue crackings i.e. the initiation and propagation of quasi-brittle cracks under the influence of loads cycled with an amplitude, ∆σ = σ_max − σ_min, where σ_max is lower than the static ultimate strength, R_m, of smooth samples, or else with an amplitude, ∆K = K_max − K_min, of the stress intensity factor, where K_max is lower than the fracture toughness, K_c, of notched samples. Fatigue cracking is a widespread source of failure of structural materials. In contrast to stress corrosion cracking, it is a variant of ‘subcritical’ crack growth which does not primarily require simultaneous racktip corrosion processes. As long as it is not enhanced by an environment, it is not corrosion fatigue and, therefore not a problem of corrosion science but of metal physics. Also, corresponding to the prime importance of the subject, the expert literature collected in monographs, in meeting volumes, and in journals is huge and far beyond the scope of the present text.