Conclusion
Fractography - Physical basics

Fractures are the result of superimposed stresses and brittle materials.

Corrosion plays a special role here: it can occur without any external force, but with internal stresses, always combined with a mechanical weakness in the metal; it can also occur without any mechanical stress, in which case it is due to a local or general electrochemical weakness in the metal.

In virtually all cases, the macrographic and micrographic surface finish is predominant.

The synthesis of these factors can be seen in the relief of the break, an image of actual past events (see article Fractography. Morphology of fractures ).