Dislocation cell formation during plastic deformation of copper single crystals

Tapered copper single crystals oriented for single slip are deformed plastically at room temperature and at 77 K. TEM investigations at resolved shear stress levels of 20, 30, and 40 MPa in the same crystal are used to follow the development of the dislocation structure with increasing deformation. Both, an open cell structure with walls preferentially aligned parallel to the primary edge orientation and planar dislocation networks are formed. Dislocation cell sizes and segment lengths are statistically evaluated. The results are discussed within the framework of a discontinuous process responsible for the decrease of the average dimensions of the microstructure with increasing applied stress.