Extended dislocation boundaries in metals subjected to plane strain deformation

Formation of extended dislocation boundaries is a characteristic feature in metals deformed monotonically. The extended boundaries have preferred orientations both in the crystallographic coordinate system defined by the crystallographic lattice and in the sample system defined by the deformation sample axes. There is an argument in the literature about whether the preferred boundary orientations are dependent on the slip system determined by the grain orientation and deformation mode. In the present paper, this argument is investigated by detailed TEM examination of boundary orientations in grains of selected orientations that constitute a critical test for the argument. The results obtained confirm that the grain orientation plays a key role in determining the boundary plane orientation.