Tailoring the formability and planar anisotropy of Al-Mg-Si-Cu-Zn alloys via cross hot rolling and two-stage cold rolling

Abstract

Al-Mg-Si-(Cu) alloys have shown great potential in responding to the growing demand for automotive lightweight, but the limited formability and high planar anisotropy have always hindered their application. The present study designs a novel method for simultaneously improving the formability and planar anisotropy of Al-Mg-Si-Cu-Zn alloys by coupling cross hot rolling and two-stage cold rolling. The results have shown that the multi-scale distribution of secondary particles and strong Brass{011}<112> and S{123}<634> texture are induced by the designed cross hot rolling process, which weakens the recrystallization texture after solution treatment, especially Cube{001}<100> orientation. Meanwhile, the designed two-stage cold rolling process (intermediate cold rolling process with high reduction + final cold rolling process with low reduction) promotes the precipitation of unstable precipitates (Mg2Si and Q phase), and inhibits the formation of Copper{112}<111> orientation, which further weakens the recrystallization texture and results in the dispersion distribution of recrystallization texture. Accordingly, the formability and planar anisotropy of the Al-Mg-Si-Cu-Zn alloy are simultaneously improved without strength loss by coupling the designed cross hot rolling with two-stage cold rolling, and the influence mechanism of texture on r value has been analyzed by Visco-Plastic Self-Consistent (VPSC) model.