Cross-slip at very low stresses in highly perfect Cu crystals

Cu crystals with special orientation submitted to a weak uniaxial tension exhibit, in X-ray topographs, zig-zag dislocations running alternately in the two glide planes containing their Burgers vector. Unloading experiments show that the junctions between two successive straight segments are anchoring points. On the hypothesis that cross-slip is initiated by dissociated jogs, a model for the formation of zig-zag dislocations is proposed.