Critical comparison of dislocation boundary alignment studied by TEM and EBSD: technical issues and theoretical consequences

The plane of extended deformation induced boundaries (geometrically necessary boundaries) determined by transmission electron microscopy (TEM) has previously been found to be grain orientation dependent so that some grains have boundaries aligned with slip planes while others do not. However, in both types of grains the boundaries are aligned with macroscopic planes. A recently published analysis by electron backscattered diffraction (EBSD) found no evidence for alignment of boundaries with slip planes or any other simple crystallographic plane, i.e. only macroscopic alignment. This discrepancy is discussed based on a critical comparison of the TEM and EBSD based techniques and TEM observations of boundary planes in grains of selected orientations in cold-rolled aluminium. The latter clearly show that the EBSD finding is incorrect. The present analysis thereby confirms that grain orientation-dependent boundary planes is a general phenomenon.