Effect of Zn addition on the microstructure, texture evolution and mechanical properties of Al-Mg-Si-Cu alloys

Effect of Zn addition on the microstructure, texture evolution and mechanical properties of Al-Mg-Si-Cu alloys was investigated by mechanical properties, microstructure and texture characterization in the present study. The results show that Zn addition has a significant influence on the evolution of microstructure and texture, and final mechanical properties. Yield strength, ultimate tensile strength and elongation increase and average Lankford coefficient r value decreases with increasing Zn content. Although the microstructure evolution in both the Zn-free and high Zn-added alloy sheets during thermomechanical processing is basically similar to each other, both the different precipitate distribution in the annealing or rolling state, and recrystallization microstructure in the solution state still can be found. Additionally, Zn addition basically does not change texture component but decrease the intensity before solution treatment. However, Zn addition has a notable effect on the recrystallization texture evolution during solution treatment. The Zn-free alloy sheet is comprised of CubeND, P and Goss orientations, while the alloy sheet with high Zn content has stronger texture consisting of CubeND, Cube, {012}<100>, {113}<392> and {023}<032> orientations. Finally, effect of texture on r value was analyzed by Visco-plastic self-consistent (VPSC) model.