Abstract
Since the surface morphology of materials can be observed with atomic-scale resolution, scanning atomic force microscopy (AFM) is a powerful technique to study mechanisms of fatigue and fracture of solid materials. In the present study, slip-band formation and fatigue crack-initiation processes in α-brass were observed by means of AFM. The depth of the intrusion drastically increased with its outgrowth to a crack. For crack-initiation from slip-band, the intrusion depth took a critical value. That is, slip distance exceeds a critical value, slip-band changes for a crack. The critical depth was almost identical between cyclic shear stress and cyclic normal stress.
