Mechanical Performance and Fracture of 3-Ply Cu/Al/Cu Clad Metals

Abstract

The mechanical performance and fracture of roll-bonded Cu/Al/Cu clad metal were investigated after heat treatment in the temperature range 200~500OC. In the roll-bonded 3-ply Cu/Al/Cu clad metal, no visible interfacial reaction compound and defects were observed at the interfaces, ensuring the well-bonded Cu/Al interface until the final moment of fracture in tension. The reaction layer was observed at the Cu/Al interface after annealing at and above 400OC, which deteriorated the ductility of clad metals. The thickness of the reaction layer increased with increasing heat treatment temperature. The periodic cracks were formed perpendicular to the tensile direction due to the strain mismatch between metal layers and the reaction compound layer in the clad heat treated at high temperatures at 500oC. The slip localization and delamination induced premature crack formation in Cu and Al layer, resulting in the decreased clad metal fracture strain, especially after heat treating at 500oC.