Development of microstructure throughout roll gap during rolling of aluminium alloys

Abstract

The mechanism of formation of substructure in the roll gap has been studied by using a specially designed roll-spring apparatus followed by rapid quenching; the metal subsequently being subjected to optical and transmission electron microscopy investigation. Experiments were conducted for single-pass and multipass deformations in order to establish the effect of a prior substructure. It is shown that an equilibrium substructure forms well before exit from the roll gap and that the accepted mechanism by which the subgrain size is altered may be in error. The authors also investigate the effect of process parameters on subgrain size and the relationships between subgrain size and room-temperature and high-temperature material properties. The experimental work was conducted using commercial purity Al and an Al–Mg alloy.