The cyclic deformation behavior of a [¯59 13]-[¯579] bicrystal, with a grain boundary which was approximately perpendicular to the stress axis, was investigated under constant plastic-strain control in air at room temperature. In particular, the bicrystal contained 2 single-slip oriented component crystals. The results showed that the cyclic stress-strain curve of the bicrystal exhibited 2 plateau regions in the axial plastic-strain ranges of 1.8 x 10-4 to 1.35 x 10-3 and 2.05 x 10-3 to 2.56 x 10-3, respectively. The corresponding plateau axial saturation stresses were about 62 to 64MPa and 70 to 71MPa. During cyclic deformation, only the primary slip system B4 (111)[¯101] within the 2 component crystals was activated (including the vicinity of the grain boundary) at all strain amplitudes. The plastic strains carried by the [¯59 13] and [¯579] grains were clearly different, due to the difference in their orientation. The surface dislocation patterns of the bicrystal were observed by means of the electron channelling contrast technique of scanning electron microscopy. The dislocation patterns in the 2 grains also exhibited an apparent difference.

Cyclic Deformation Behaviour of a Copper Bicrystal with Single-Slip Oriented Component Crystals and a Perpendicular Grain Boundary: Cyclic Stress-Strain Response and Saturation Dislocation Observation. Z.F.Zhang, Z.G.Wang: Philosophical Magazine A, 1999, 79[3], 741-52