Definition - What does Fatigue Striation mean?
Fatigue striations are marks that are found on a material when it has been subject to fatigue failure. There can be hundreds of fatigue striations on the surface of a material that failed due to fatigue.
Fatigue striations are microscopic and cannot be readily seen with the naked eye. Most fatigue striations can only be viewed under magnification greater than 100x.
Corrosionpedia explains Fatigue Striation
Fatigue striations occur as a result of fatigue failure. Each fatigue striation is usually indicative of a fatigue cycle that propagates a fatigue crack further into the base material. Since fatigue striations are created by fatigue cycles, they can be counted and used to determine how many crack propagation cycles occurred before final failure. It should be noted however that fatigue striations do not always directly correlate with the number of cycles a specimen underwent.
Fatigue striations and beach marks are often confused with one another because they are both related to fatigue failure. One major difference is that beach marks can be seen at the macroscopic level. Fatigue striations, on the other hand, are microscopic. One beach mark can contain a large number of fatigue striations.