Lattice orientation dependence of the stored energy during cold-rolling of polycrystalline steels

During cold deformation, about 10% of the energy spent is stored in the polycrystalline material in the form of the elastic energy associated to crystal defects. The latter can be measured experimentally by calorimetry, X-ray diffraction. In this work, we propose a direct calculation based on an elastic-plastic self-consistent model, The part of the stored energy related to second order (intergranular) stresses is estimated for a cold-rolled Ti-IF steel. The stored energy as well as the accumulated plastic strain are reported as a function of the final crystallographic orientation of the grains. Along the alpha -fiber, the stored energy increases from {001}< 110 > to {111}< 110 > while the plastic strain decreases. This dependence with the crystallographic orientation is in good agreement with experimental results. With respect to recrystallization, experiments show that {111}-grains nucleate first. This highlights the specific role of second order (intergranular) stresses for recrystallization. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.