Effect of Rolling Process on Formability and Mechanical Properties of AA 1050/Mg AZ31B Bilayer Sheet

This paper presents an experimental investigation of the rolling process's impact on the formability and mechanical characteristics of the AA 1050/Mg AZ31B bilayer sheet manufactured by explosive welding. Different thicknesses of composite bilayer sheets can be achieved by the work hardening of the explosive-welded Al/Mg composite sheet. The most important point is the simultaneous rolling process's impact on the formability and mechanical characteristics of the bilayer sheet. In this research, Al/Mg bilayer sheet was first prepared by an explosive welding technique. Then, it was cooled down to room temperature in the furnace for 24 h after being annealed for 2 h at 250 °C. The rolling process was performed with reduction ratios of 10 and 20%. The strength, elongation, stress–strain diagram, and forming limit diagram, as well as the microstructural examinations, are compared in the three cases of unrolled bilayer sheets and rolled bilayer sheets with reduction ratios of 10 and 20%. The results show an increase in strength and a decrease in elongation after the rolling process of the bilayer sheets. Moreover, the strength also rises with an increase in the reduction ratio. Besides the strength enhancement, the sheet hardness is also improved due to the rolling process. The hardness improvement in the interface can be associated with forming of brittle intermetallic compounds. The rolling process also causes a drop in the forming limit diagram. Moreover, the formability is decreased by increasing the reduction ratio. The respective reduction of 25 and 49% are observed in FLD₀ values for the reduction ratios of 10 and 20% as compared to the unrolled bilayer sheet.