BLOCK-MODELS AND (011)[100]RECRYSTALLIZED ORIENTATION IN COLD-ROLLED SINGLE-CRYSTALS OF ALPHA-IRON - A CRITICAL-REVIEW

The block theory for recrystallization nucleation proposed by B. F. De cker and D. Harker (D-H) has been critically reviewed in the light of recent experimental evidence and slip system geometry. Unpublished as well as available data of pole figures of e.g. (011) [100]-oriented si ngle crystals of Fe-3%Si have been used for discussion. The experiment al results on which the D-H theory was based are found to be incorrect , For example, Goss recrystallized texture is developed in crystals ro lled at reductions higher than 60%, while in case of D-H reduction was 40%. Operative slip systems on rolling have been estimated using Tayl or factor, and lattice rotation has been analyzed. On this basis, exis ting block models have been discussed and classified into ''hard'' and ''soft'' block models in view of the relation between local deformati on within blocks and total deformation by rolling. The Goss recrystall ized orientation was formed from cold rolled {111}< 211 > orientation by a reverse lattice rotation; ie. the rotation direction is opposite to the direction caused by rolling deformation. This fact has been use d to discuss the validity of the models. Preference of the hard model has been emphasized. The D-H model belongs to the soft model, but with this it is not possible to give reasonable explanations.