Abstract

The misorientations existing between subgrains are of critical importance in understanding the nucleation and growth of recrystallised grains. In this paper it is demonstrated that, because of spherical aberration and focus error in the objective of a conventional 100 kV electron microscope, the accuracy of beam direction determination is a function of the size of the area selected, when this area is small. Various factors are discussed, and it is shown that for beam direction determination to within 2° accuracy over the whole unit triangle using a modern 100 kV microscope, that the minimum area must be greater than 1.5 μm diameter. The implications of this on previous conventional SAD deformation texture studies, where the subgrain size is typically ∼ 2,500 Å, are discussed.