SUBGRAIN GROWTH IN HEAVILY DEFORMED ALUMINUM-EXPERIMENTAL INVESTIGATION AND MODELING TREATMENT

A comprehensive study of the annealing behaviour of two variants of commercial purity aluminium alloys has been carried out. The primary objectives of this work have been to improve the understanding of the recovery processes in itself as well as to study the effect of recovery on the annealing behaviour of heavily deformed aluminium. The experimental part has focused, firstly on describing the as deformed structure with emphasis on sub-boundary misorientations and long range lattice curvature, secondly on following subgrain growth and characterization of the softening reaction. The modelling part treats subgrain growth as a reaction controlled by sub-boundary migration. The significance of sub-boundary flexibility in this context is emphasized, an aspect which requires lateral drift of ledges as an important element in the boundary migration mechanism. A subgrain growth model based on thermally activated migration of ledges has been developed and applied to the experimental results.