Atomic Force Microscopy Study of the Early Fatigue Damage
The possibilities of atomic force microscopy in studying surface features and early fatigue damage in materials are reviewed. Examples of a true relief arising on the surface of cyclically strained materials as recorded by atomic force microscopy are given. Characteristic features of the surface relief are well-defined persistent slip markings consisting of extrusions and intrusions. The shape of extrusions and intrusions can be obtained by observation of metal surface and replicas and in combination with high resolution scanning electron microscopy. The growth of extrusions during fatigue life is reported for austenitic and ferritic stainless steels. The experimental data are compared with models of the localized cyclic plastic straining and predictions of the fatigue crack nucleation models.
J. Polák et al., "Atomic Force Microscopy Study of the Early Fatigue Damage", Materials Science Forum, Vol. 482, pp. 45-50, 2005