Deformation behavior and crack propagation on interface of Al/Cu laminated composites in uniaxial tensile test

The microstructural characterization and uniaxial tensile tests of Al/Cu laminated composites were taken to investigate the interface effect and fracture process of the composites. The electron microscopic graphs before and after tensile test were used to evaluate the fracture behavior. Experimental results show that the fracture surfaces of laminated composites mainly present brittle failure characteristics, accompanied with several dimples on the matrixes and a few tearing on the interface. Cracks generally initiate from the interfacial interlayer and variously propagate depending on the interfacial bonding. It is found that Cu/Al interface with enhanced bonding strength generally hinders the propagation of interlayer cracks, while the interface with weak bonding delaminates by the cracks propagation through the interfacial defects. The additional shear stress on the interface between Cu and Al layers due to their different tensile ductilities aggravates the interfacial propagation of cracks. The local plastic deformation of individual matrix layer then occurs after cracks coalesce and failure in the interface. Therefore, the strong bonding interface and matching properties between individual matrix layers are required to improve the fracture performance of Al/Cu laminated composites.