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

A comprehensive study of the annealing behaviour of two variants of co mmercial purity aluminium alloys has been carried out. The primary obj ectives of this work have been to improve the understanding of the rec overy processes in itself as well as to study the effect of recovery o n the annealing behaviour of heavily deformed aluminium. The experimen tal part has focused, firstly on describing the as deformed structure with emphasis on sub-boundary misorientations and long range lattice c urvature, secondly on following subgrain growth and characterization o f 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 whic h requires lateral drift of ledges as an important element in the boun dary migration mechanism. A subgrain growth model based on thermally a ctivated migration of ledges has been developed and applied to the exp erimental results.