Microstructure and tensile behavior of Cu–Al multi-layered composites prepared by plasma activated sintering

Multi-layered Cu/Al composites were fabricated with Cu and Al foils by using plasma activated sintering (PAS) process. Microstructure analysis revealed that the interfacial zone between the Cu and Al consisted of Al4Cu9, AlCu and Al2Cu individual layers, where the Al4Cu9 layer was dominant. In situ observation during the failure process of the Cu/Al multi-layered composite under tensile loading indicated that the failure was initiated by crack generation in the intermetallic layers. With increasing load, these cracks propagated into the Al layers along the Al grain boundaries, but got blunt at the intermetallic/Cu interface instead of penetrating into the Cu layers. Cracking of the intermetallic and Al layers in turn led to local plastic deformation of the copper layers. The localized deformation, which was confined to the small regions between the opposite cracks in the neighbouring intermetallic layers, was prolonged till the composite failure.