The Nature of Intermetallic Compounds and its Effect on Mechanical Properties of Cu/Al/Cu Clad Metals

Abstract

The mechanical properties and microstructure of layered Cu/Al/Cu composites was investigated after annealing at various temperatures. The nature of intermetallic compounds in roll-bonded Cu/Al/Cu clad metals after heat treatment was investigated using SEM, XRD and EBSD.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. The reaction layer was observed grow rapidly at the Cu/Al interface after annealing at and above 400oC, which deteriorated the ductility of clad metals. Intermetallic reaction layers of Cu/Al/Cu clad materials annealed at 500oC for 3, 5, 10hours was found to consist of three layers, CuAl2, CuAl and Cu9Al4. EBSD analyses revealed that intermetallic layers are polycrystalline. The drastic decrease of stress and elongation in Cu/Al/Cu clad composite annealed at 500oC can be linked to the interfacial cracks between Al and Cu layer.