Mechanical Fatigue Fracture

Fatigue fractures account for the highest proportion of fracture failures. To determine whether a component's fracture is due to fatigue, it is not difficult to judge based on the macroscopic morphology of the fracture surface and the stress conditions.

Combining this with microscopic analysis of the fracture surface allows further analysis of the effects of load characteristics and environmental factors, thereby determining the type of fatigue fracture.

High-Cycle Fatigue Fracture

Generally, high-cycle fatigue fractures occur when the surface of a component is relatively smooth, and the fracture surface has one or several fatigue origins.

For components subjected to relatively low cyclic loads, the majority of the fracture surface area is the fatigue propagation region.

The microscopic morphology of a high-cycle fatigue fracture surface shows fine fatigue striations, as shown in below figure.