Critical Fracture Behavior of a Cu/Al Composite Laminate via the Observation of Scanning Electron Microscope

Abstract

In situ fracture study of a Cu/Al composite laminate was discussed via the observation of scanning electron microscope (SEM). The experimental test was carried out by a modified miniature tensile device. With the aid of the SEM's sample stage and a wedge block, the profile morphology of the specimen was observed. The substrate layer (1060 aluminum) and the plate layer (C11000 copper) of the specimen presented asynchronous fracture behaviors. Under a relative large strain, a mass of micro voids, cracks and connections of voids and cracks were observed in the substrate layer, accompanied with some separated copper oxide and aluminum oxide flakes. Micro cracks were also observed in the plate layer and the overall morphology of the plate layer was relatively smooth and flat. When the tensile strain increased to 0.26, the initial fracture position firstly occurred at the plate layer, and the fracture process gradually spread from the plate layer to the substrate layer. In addition, the fracture modes of the substrate layer and the plate layer mainly manifested as microvoid coalescence fracture and pure shear fracture, respectively.