Striations and Fatigue Cycles

The question of whether or not a single striation would correspond to a single fatigue cycle was first answered by Forsyth e Ryder [43] who used programmed constant amplitude fatigue cycles spaced by overload marking cycles. On the fracture surface it was possible to pick up these overload markers that were 

2 Morphological Aspects of Fatigue Crack Formation and Growth 

Albeit fatigue striations are due to a plastic flow that opens and blimts crack tip, an important role in their visibility, at least with the aid of the electron microscope, is played by corrosion or, at least, oxidation. It has long been recognized that 

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