Size dependence of fatigue damage in sub-micrometer single crystal gold

In fatigue, micrometer and sub-micrometer metal components do not have sufficient space to form persistent slip band (PSB) structures, which bring about the extrusions/intrusions with the size of a few micrometers in bulk metal. The characteristic feature of fatigue behavior at this scale is investigated using resonance vibration fatigue experiments on single crystal gold cantilevers of various sizes. Fatigue damage of extrusion/intrusion is formed on the cantilever surface in all specimens. The width of the extrusion/intrusion decreases with the size of cantilever, from hundreds to tens nanometers, which is much smaller than that in bulk components. And the slip traces formation is spatially periodic. The resolved shear stress to form an extrusion/intrusion is strongly dependent on the specimen size and is much higher than that in the bulk.