Study on the Rolling Forming Process of Mg/Al Composite Foils with Low Edge Cracking

Edge cracking is prone to occur during the rolling of Mg/Al composite foils. Herein, a hybrid hot-cold rolling process was adopted to fabricate 30 μm thick Mg/Al composite foils with low edge cracking. AZ31B magnesium alloy and 5052 aluminum alloy sheets, both with an initial thickness of 0.5 mm, were chosen as research materials. Numerical simulations of composite pass were conducted at 300-450 °C with reduction ratios of 25-40%, and the optimal parameters were identified as 400 °C and a 35% reduction ratio. Based on this, multi-pass rolling experiments were performed: composite pass was heated at 400 °C for 10 min with 35% reduction ratio, hot rolling passes at 300 °C for 1-3 min, and subsequent cold rolling with 15% reduction ratio. After 21 rolling passes, 30 μm thick Mg/Al composite foils with low edge cracking were successfully prepared. Interface and metallographic characterizations demonstrated that the diffusion layer thickness varied slightly during hot rolling and increased moderately during cold rolling. For the magnesium alloy, hot rolling improved microstructural uniformity and reduced shear bands, while cold rolling caused decreased uniformity and the gradual emergence of shear bands. The research results provide a reference for the preparation of high-quality Mg/Al composite foils.