Static recrystallisation kinetics of commercial aluminium: influence of hot deformation mode

Abstract

The kinetics of static recrystallisation and the recrystallised grain size of a commercial aluminium alloy have been determined after both hot torsion and axisymmetric compression within the steady state regime. Annealing of the specimens, quenched after hot deformation in both modes at 325 and 360°C, was carried out at 410°C. The presence of dynamically formed grains developed during deformation, which can act as pre-existing nuclei, exerts an influence on the subsequent static recrystallisation behaviour of the alloy. The increase in number of these dynamically formed grains with strain explains the significant effect of strain in the steady state. However, some differences result from the different modes of deformation. Hot axisymmetric compression leads to an important decrease of both the time to reach a recrystallised fraction of 50% and the recrystallised grain size in comparison with hot torsion. The different deformation modes, through their effect on the spatial distribution of particles, seem to affect the proportion of dynamically formed grains which become effective nuclei and therefore the recrystallisation kinetics. In addition, particle drag effects can influence greatly the static recrystallisation kinetics.

MST/1810