Fatigue Striations

The microscopic features on a fatigue fracture surface that identify each individual propagation cycle of a fatigue crack. They are not always present and can only be seen under a scanning electron microscope. When visible, fatigue striations can be used to estimate the number of fatigue cycles a component has undergone. In contrast, beach marks are macroscopic fatigue features marking an interruption of some sort in the fatigue cracking progress. Both beach marks and striations can be used to identify fatigue fractures.