Crystal growth in deformed metals by an impingement and spheroidisation process

Abstract

In a detailed scanning electron microscope study of the recrystallisation of an IF steel it was observed that the new grains went through an equiaxed stage which became elongated along the rolling direction and then became equiaxed again when recrystallisation was complete. A theory of how the final crystal structure arises from the deformed matrix is proposed in which grain impingement during growth, when it involves orientation pinning, is followed by crystal aggregate spheroidisation to give the final polycrystalline structure. This means that a proportion of grains in a recrystallised aggregate have arisen from several separate nucleation events. The model, which is general, has implications for texture formation and can apply to both primary and secondary recrystallisation. It can also explain why the grain growth exponent is usually measured to be between 2 and 3. © 2003 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.