Effects of strain path on the microstructure, tensile properties, and formability of Al/Mg roll-bonded sheets

Abstract

In this research, the experimental investigation of the change of the strain path on the microstructure, mechanical properties and the forming limit diagram of Al/Mg two-layer sheet made by roll bonding method has been performed. This research tries to make a two-layer Al/Mg sheet with a reduction ratio of 55% by using four single-pass and two-pass (the first pass with a reduction ratio of 40% and the second pass by changing the strain path in the form of direct rolling, reverse rolling and cross rolling) methods. The results show that the microstructure in cross rolling is more uniform than in other cases. No delamination is observed in fabricating the bilayer sheets with two passes. The best mechanical properties in terms of ultimate tensile strength and elongation are related to cross-rolled samples. Also, the cross rolling process causes a significant reduction in normal anisotropy. The comparison of formability for different conditions indicates the improvement of the forming limit diagram in cross rolling so that the amount of FLD0 for cross-rolled samples has increased by 15.6%, 13.8%, and 5.7%, respectively, compared to single-pass, two-pass direct rolling, and two-pass reverse rolling samples.