Microstructure evolution of Al/Mg/Al laminates in deep drawing process

Abstract Magnesium based laminates have been successfully prepared by various methods. Their microstructure and mechanical properties have also been fully discussed. However, there are few reports on their formability which is essential to further manufacture and application of laminates. In this paper, hot-rolled Al/Mg/Al laminates were used to conduct deep drawing at various temperatures, and microstructure evolution of three typical regions including bottom, corner and wall taken from the drawn cylindrical part with the largest limit drawing ratio (LDR) was also investigated. No delamination is observed in deep drawing. The value of LDR grows with increasing forming temperature, reaching a peak value of 3.1 at 200 °C, which is higher than that of as-rolled Mg or Al sheet, although there exists brittle intermetallics at Mg/Al interface. The reason is that varying degrees of fracture in intermetallic layers helps to release stored energy and facilitate coordinated deformation. At corner region of cylindrical part drawn at 200 °C, fragment is observed in intermetallics. For cylindrical part drawn at 200 °C, Mg layer at bottom, corner and wall regions all exhibit basal texture, but c-axes of Mg grains gradually change orientation from tilting toward the RD to tilting toward the TD. The increasing extent of DRX greatly refine the Mg grains and weaken the basal texture. Continuous recrystallization changes the texture of Al layer. The corner region shows a random texture with the lowest intensity of 4.14, and the bottom and wall regions both exhibit cubic texture.