Evolution of microstructures in severely deformed AA 3104 aluminum alloy by multiple constrained compression

AA 3104 aluminum alloy was severely deformed by multiple constrained compression in a channel die set-up. The evolution of microstructures during deformation was investigated by transmission electron microscopy. The flow stress in multiple constrained compression initially increases markedly with strain and then increases gradually. Large scale shear bands and the evidence for strain localization are observed. The microstructure consists of dislocation cells and extended boundaries after two passes to a strain of 0.86, while a cell block structure with high-angle lamellar boundaries is formed after eight passes to a strain of 3.56.