Dislocation structures in cyclically deformed co-planar [¯255] and [¯233] double-slip oriented single crystals were studied by using transmission electron microscopy and were related to the macroscopic mechanical behavior. The experimental results indicated that the crystallographic orientation had almost no effect upon the cyclic stress-strain behavior and dislocation structures of [¯255] or [¯233] co-planar double-slip oriented single crystals. The cyclic dislocation structures of co-planar double-slip crystals consisted mainly of dislocation cells whose scale decreased with increasing applied strain amplitude. Under certain applied strain amplitudes, the observed dislocation cells exhibited different features: including dislocation wall-like and persistent slip band ladder-like features. These favoured the accommodation of much more plastic strain during cyclic deformation. The occurrence of a quasi-plateau in the cyclic stress-strain curve of co-planar double-slip oriented Cu single crystals, where the stresses exhibited a slow increase with plastic strain amplitude, was suggested to result from the joint effects of a change in scale of the cell structure and the formation of a persistent slip band ladder-like cell structure.

Dislocation Structure in Cyclically Deformed Coplanar Double-Slip Oriented Copper Single Crystals. X.W.Li, Z.G.Wang, Y.W.Zhang, S.X.Li, Y.Umakoshi: Physica Status Solidi A, 2002, 191[1], 97-105