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An aluminium single crystal with [110] initially parallel to the tensile axis and (1 • 11) initially parallel to the front face of the crystal was elongated by 30%. Macroscopic deformation bands were visible on the broad face of the crystal after deformation. To explore the deformation-band characteristics, crystal orientations were measured using the electron-backscatter-di¬raction (EBSD) technique over large areas on the front face and on a cross-section of the specimen. The measured lattice orientations demonstrate that crystal-rotation axes are not restricted to the plane normal to the tensile direction, as considered by standard analyses. An extra constraint imposed by the rectangular specimen geometry is proposed to generate lattice rotation around the tensile axis. An analysis is developed that transforms each local crystal-orientation measurement into a set of local shear amplitudes for the four critically stressed slip systems. Based on the EBSD observations and shear-amplitude analysis, three types of deformation bands are identi ed in the deformed crystal. On a microscopic scale, classic kink bands not exhibiting secondary slip traces and secondary slip bands are present, although these correspond to relatively minor shearamplitude inhomogeneities. On a macroscopic scale, bands previously denoted special bands of secondary slip (SBSS) are shown to be coarse kink bands exhibiting secondary slip. SBSS are shown to have an internal structure consisting of smaller lamellar domains in which slip on (111) and ( • 1 • 11) predominates alternately.

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