Through-thickness variations in recrystallization behavior in an Al-based ARB composite sheet

Abstract

A composite sheet of commercially pure aluminum and an Al-0.3 wt.% Sc alloy (in the supersaturated solid solution condition) was produced by accumulative roll bonding at 200°C. The material was then subjected to isothermal annealing at 300°C for 1-30 minutes and cold water quenched. The transverse section was investigated by electron back-scatter diffraction (EBSD) to investigate the variations in microstructure and texture within Al layers through the sheet thickness. A faster spheroidization of the highly elongated lamellar band deformation structures was observed in the surface aluminum layer as compared to the mid- and quarter-thickness layers. In the quarter thickness aluminum layer so-called continuous recrystallization occurred and, thus, the p-fiber rolling texture was retained. Further growth in this layer led to secondary recrystallization of cube orientations. In contrast, in the surface aluminum layers the recrystallization and grain growth texture were relatively random. Intermediate behavior was observed in the mid-thickness aluminum layer.