GRAIN BOUNDARY PLANE DISTRIBUTIONS IN THE COLD-ROLLED AND ANNEALED FERRITIC STAINLESS STEEL

The grain boundary plane distribution in the cold rolled and annealed ferritic stainless steel has been analyzed statistically by a five parameter method based on the mis-orientations of adjacent grains and the orientations of grain boundary traces determined by electron backscatter diffraction (EBSD) attached to a field emission scanning electron microscope (FE-SEM). The results show that no preferred texture occurrs either in grain orientations or grain boundary mis-orientations characterized by axis angle pairs in the specimens which were cold rolled by 85% reduction in thickness and subsequently annealed at 780 degrees C. However, there are developed textures for the orientations of grain boundary planes. Anti also, the preferred planes vary with averaged grain size levels. At the level of 9 mu m, grain boundary planes favor the {100} orientation, with their density distribution 12% higher than a random distribution; Whereas at the level of 15 mu m, {111} planes are preferred and {100} and {112} planes are sub preferred, with the density distribution on {111} about 10% higher than a random distribution. Moreover, the anisotropy of grain boundary plane distributions is larger at specific mis-orientations. The discussion points out the preferred grain boundary planes might possess lower energies and tend to being preserved due to their lower growth rates during annealing.