Corrosion fatigue definition

This behavior is characterized by a plateau region, which prevails above a definite threshold K. It is often referred to as stress-corrosion fatigue because SCC systems usually exhibit this behavior, and the most common theory assumes that the crack growth rate results from the addition of SCC, and pure fatigue crack advance. This is a type of... 

FYom the multitude of intricate corrosion processes in the presence of mechanical action (friction, erosion, vibration, cavitation, fretting and so on) it is justified to touch upon corrosion types joined under a single failure mode induced by mechanical stresses. These are the stresses that govern the corrosion wear rate of metals during friction. Such processes are usually called corrosion stress-induced cracking in the case that the mechanical action is effective only in one definite direction, or otherwise termed corrosion fatigue in the case that compressive and tensile stresses alternate within cycles. In spite of the differences between the appearance of these corrosion types, they have much in common, e.g. fundamental mechanisms, the causes, and they overlap to a certain degree [19]. 

In the more recent literature, the term strain-induced corrosion is commonly found, which is a generic term for nonclassical stress corrosion cracking, corrosion fatigue with low cycle frequency, and strain-induced corrosion cracking. For the purposes of a clear distinction between the different types of cracking, this term should be replaced by the definitions below. 

The depths of deepest pits on specimens, the times to first leaks in pipe lengths, times to initial stress-corrosion cracking failures, and the number of cycles to first corrosion-fatigue failures are, by definition, extreme values. The depth of the deepest pit on a specimen is the upper tail of the distribution of depths of all pits on that specimen. 

The maximum repeated stress that can be endured by a metal without failure under definite conditions of corrosion and fatigue, and for a specific number of stress cycles and a specified period of time. 

---