High strain rate tensile performance and microstructural evolution of Al/Cu laminated composite under dynamic loading

The tensile tests at high strain rates ranging from 10 s−1 to 500 s−1 were conducted for the Al/Cu laminated composite produced by asymmetrical roll bonding and annealing. The microstructural evolution after tensile test was observed by SEM, EDX and TEM to analyze the strain rate effect on the laminated composite. It is found that the ultimate tensile strength increases obviously with the rise of strain rate, but the elongation reduces drastically. The deformation-induced twins form in the Cu matrix during the dynamic loading, and the strain-rate strengthening effect promotes the compatible deformation between matrix layers and interfacial interlayer. Thus, a good bonding interface is maintained in the composite after fracture at the strain rate above 100 s−1. Some deformation bands form in the matrix layers due to the significant dislocation multiplications and tangles in grain boundaries along the tensile direction in the high strain rate deformation.