Lattice rotation in polycrystalline aggregates and single crystals with one slip system: a numerical and experimental approach

In this study, lattice rotations in polycrystals and single crystals with one slip system have been analysed for pure shear and simple shear by re-visiting previously published data and by conducting new numerical models that are compared with results from experiments on polycrystalline ice. The numerical models are based on the finite-difference method and on the assumption that dislocation glide on one slip system is the dominant crystalline deformation mechanism and is controlled by the critical resolved shear stress law. Such a deformation scheme corresponds to the operation of glide on (0001) in polycrystalline ice used in the physical deformation experiments. The results show that lattice rotation is primarily controlled by the bulk deformation kinematics in both the polycrystalline aggregates and the single crystals. In the single crystals the lattice rotation is entirely consistent with the vorticity of the bulk deformation kinematics, whereas in the polycrystalline aggregates extensive grain interactions significantly modify the local lattice rotations and may even lead to the lattice planes of individual grains rotating in an opposite sense to that of the bulk deformation. These results can reasonably explain the development of crystallographic preferred orientations widely reported in the literature.