Fatigue Crack Paths 2003

Fractography

Fractographic analysis was carried out in order to describe the main mechanisms of the

fatigue crack growth in studied alloys. Fracture surfaces were first observed by a light

microscope and then using scanning electron microscopes. The fractographic findings

based on detailed observation of all fracture surfaces in the magnification range from

20 to 20,000 times are as follows:

i) Rugged fracture surfaces consist of facets different in the arrangement, size, and

micromorphology (Fig. 2).

Figure 3. Cleavage facets with a step on Figure 4. Quasicleavage facets on

fatigue fracture.

fatigue fracture.

Figure 5. Fatigue striations produced by mechanisms of cyclic brittle cleavage.