Crystallographic aspects of nucleation and growth during primary recrystallization in stable single crystals of Al and Al-1%Mn alloy

Abstract

The early stages of recrystallization have been characterized in stable, single crystals of Al and an Al-1%wt. Mn alloy to rigorously quantify the orientation relations between nuclei and simple deformation structures. Goss{110}<001> and brass{110}<112> oriented samples were deformed in a channel-die to develop a homogeneous structure composed of two sets of symmetrical microbands and then lightly annealed. SEM/EBSD analyses demonstrate a strong relation between as-deformed orientations and the limited number of recrystallized grain orientations. The misorientation angles across the recrystallization front are mostly grouped in the ranges of 25-55° around axes located near, but not at, the normals of all four {111} planes. In some cases the orientation of the growing grain transforms through the formation of a first generation twin with the twinning plane normal lying near the rotation axis. The intensity of new grain nucleation in near-surface areas is significantly greater than those observed in central parts of the sample. Many new grains grow from the surface into the sample centre mostly along the {111} planes. However, irrespective of the section new grains possess the same type of orientation relationship with respect to the deformed state.