When face-centered cubic single crystals with high-symmetry crystal orientations were deformed to moderate strains by rolling, tension or channel die compression, long dislocation boundaries inclined to the extension axis formed. Similarly, long dislocation boundaries were often found in grains embedded in polycrystals deformed in the same manner. These extended planar boundaries were characteristically ±30-40° from the extension direction and contained the transverse specimen axis. The present objective was to demonstrate that extended planar boundaries formed during plane strain deformation were parallel to equivalent slip planes, a pair of hypothetical slip systems used for analyses of the strain and crystal rotation components in place of the larger number of physical slip systems. The coincidence of extended planar boundaries and equivalent slip plane inclinations was shown to account for persistent observations of extended planar boundaries in the angle range ±30-40° from the rolling direction, in rolled single crystals of various initial orientations. The tendency of extended planar boundaries towards tilt or twist boundary character could also be rationalized on the basis of the equivalent slip system concept and consideration of the dislocation types available to be incorporated into extended planar boundaries.

Extended Planar Boundary Inclinations in FCC Single Crystals and Polycrystals Subjected to Plane Strain Deformation. J.A.Wert, X.Huang: Philosophical Magazine, 2003, 83[8], 969-83