Modelling the Transition from Discontinuous to Continuous Dynamic Recrystallization with Decreasing Purity in Aluminium

Abstract

Commercial purity and low alloyed aluminium undergo continuous dynamic recrystallization during hot deformation. By contrast, discontinuous dynamic recrystallization has been recently reported in ultra high purity aluminium (>99.999%). Continuous dynamic recrystallization is expected to occur when the time needed to transform a subgrain boundary into a large angle grain boundary is significantly smaller than the time necessary for a mobile grain boundary to sweep a distance equal to the microstructure size. In order to better understand the transition between the two types of recrystallization, the influence of material purity on the controlling parameters (misorientation rate, grain boundary fraction, boundary migration rate, microstructure size) is investigated by using a model previously developed to describe continuous dynamic recrystallization.