Metals are polycrystals and consist of grains, which are subdivided on a finer scale upon plastic deformation due to formation of dislocation boundaries. The crystallographic alignment of planar dislocation boundaries in face centred cubic metals, like aluminium and copper, deformed to moderate strains at room temperature are analysed. A major result is that, by contrast to previous beliefs, the boundaries align with specific crystallographic planes, which depend on the crystallographic grain orientation. This grain orientation dependence originates from an underlying dependence of the active slip systems. Actual prediction of the dislocation boundary alignment has become possible through establishment of general relations between slip systems and dislocation boundary planes. The practical relevance of these relations has been exemplified by applying them as a basis for further prediction of the mechanical anisotropy of rolled sheets. The rotation of the crystallographic lattice in each grain during deformation also exhibits grain orientation dependence, originating from the slip systems. A combined analysis of dislocation boundaries and lattice rotations concludes that the two phenomena are coupled through their common dependence on the slip systems.
Materials characterization and modelling; Materials research; Risø-R-1686; Risø-R-1686(EN); Materialeforskning; Materialekarakterisering og materialemodellering