Bulging Ability and Microstructure Evolutions of Al/Mg/Al Laminate

Formability of Al/Mg or Al/Mg/Al laminates is essential to their further manufacture and application. However, there are few reports on their formability compared with the investigation on their microstructures and mechanical properties. In this paper, bulging deformation of Al/Mg/Al laminate was conducted at 170, 200, and 230 °C. The results show that both temperature and strain state affect the formability of laminate, and the peak dome height of 36.5 mm was obtained at 230 °C under equibiaxial tensile strain. Further texture analysis indicates that Mg layer exhibits basal texture with most grains elongated along the rolling direction, and continuous dynamic recrystallization occurs during the bulging process. Necking or fracture positions of bulging parts appear at outer rings, not at the apex with the highest deformation degree. For the same strain state and direction, the range of necking or cracking is extended and wall thickness along different directions is uniformized when temperature rises. Interfacial structure observation shows that cracking occurs in various positions in bulging, including in AlMg, at Al/AlMg, MgAl/AlMg, and MgAl/Mg interfaces, which is almost impervious to temperature.