Fine-grained copper films on a flexible substrate were cyclically deformed under constant strain range control. It was found that cyclic dislocation plasticity through individual dislocation glide was still dominant at the sub-micrometer scale, while the ability of irreversible slip of dislocations gradually decreases and the damage was changed from extrusion-induced localization to cracking along grain boundary. Statistical evaluation of the mean spacing between slip bands and/or lines leads to a critical scale (∼28nm) below which dislocation-controlled cyclic strain localization would be shut down.

On the Length Scale of Cyclic Strain Localization in Fine-Grained Copper Films . B.Zhang, K.H.Sun, Y.Liu, G.P.Zhang: Philosophical Magazine Letters, 2010, 90[1], 69-76