Variant Selection During the Primary Recrystallization of Cold Rolled Ferrite

摘要

The rotation axes associated with the recrystallization of both lightly and heavily rolled materials are reviewed. In the case of sheets with weak textures that have been lightly deformed, the "transformation" of the texture can be described in terms of <110> axis rotations. Such rotations are evidence for the occurrence of selective growth by the mechanism of plane matching. As all six crystallographicaly equivalent <110> axes participate in this process, there is no variant selection in this case. under these conditions, strain induced boundary migration (SIBM) or "low stored energy nucleation" can be considered to take place. By contrast, when sharply textured materials are heavily deformed, with the result that either random or high stored energy nucleation occurs, only those <110> axes in the vicinity of the maximum shear stress poles are involved in the transformation. The choice of rotation axis is ascribed to the presence of the deformation substructure, sheets of which lie approximately parallel to the maximum shear stress planes. Such sleective growth involving variant selection is responsible for conversion of the RD into the ND fibre during annealing. Further work is needed to establish the importance of variant selection in moderately strained sheets.