The dependence of final microstructure, texture evolution and mechanical properties of Al–Mg–Si–Cu alloy sheets on the intermediate annealing

Abstract

Effect of intermediate annealing on the microstructure, texture and mechanical properties of Al–Mg–Si–Cu alloy sheet in the different conditions was investigated by means of tensile test, microstructure characterization and texture measurement in this study. The results show that, three different intermediate annealing treatments (no annealing, low temperature annealing, high temperature annealing) have a great influence on the evolution of microstructure and texture, and final mechanical properties. Compared with the high temperature annealing and no intermediate annealing, the low temperature annealing is most beneficial to improve mechanical properties, especially for improving the average Lankford coefficient r and reducing Δr values, and to form the uniform recrystallization structure and the finer recrystallization grains. Although the intermediate annealing temperature only affects the intensities of textures formed by annealing treatments, and the intensities of β fibers formed by the following cold rolling, yet, the texture components are quite different in the three alloy sheets in the T4P state, and only the CubeND orientation produced by PSN effect appears in the alloy sheet treated by the low temperature annealing. Additionally, the relationship between texture, r value and yield strength was analyzed by VPSC model and slip theory in this paper.