A detailed investigation was made of the motion of grain boundaries during the cyclic deformation of bicrystals of very high purity material. Bicrystals which contained various types of grain boundary were studied in order to determine the effect of grain boundary type upon the behavior under cyclic loading. The evolution of the microstructure was measured by means of electron back-scattering diffraction and scanning electron microscopy. During cyclic deformation, a specific structure appeared within each grain. The nature of the deformation structure and, in particular, the difference in dislocation density on each side of the grain boundary was found to be responsible for the displacement of the boundaries. A model was proposed in order to explain grain-boundary motion and grain-boundary alignment during the cyclic deformation of Al bicrystals.

Grain Boundary Motion during High-Temperature Cyclic Deformation of High-Purity Aluminium Bicrystals. S.Weiss, G.Gottstein: Materials Science and Engineering A, 1998, 256[1-2], 8-17