Effect of heat treatment on bonding mechanism and mechanical properties of high strength Cu/Al/Cu clad composite

The present study is aimed at fabricating Cu/Al/Cu tri-layered clad composite with one pass heavy reduction roll bonding and subsequent heat treatment. High strength clad composite was designed via introducing 7075 alloy. The interface bonding mechanism was discussed under different conditions. The mechanical properties of the Cu/Al/Cu clad composites were also studied. The results showed that thick interfacial intermetallic layer could be formed after certain heat treatments (annealing at 500 degrees C or T6 treatment). The peeling behavior was affected by the intermetallic layer. The interfacial bonding behavior was related with the state of Cu/Al/Cu clad composite. Peel strength could reach 78.1 or 62.2 N/cm after annealing at 500 degrees C or T6 treatment, respectively. Lamellar delamination traces were remained on the peel surface after peel process. The thickness of interfacial compounds was in proportional with the altitude of delamination remaining. During the peel process, peel gap sheared through the interfacial layer and transformed between two matrix layers periodically. The mechanical properties of present clad composite could reach a best comprehensive value after T6 treatment with strength of 458 MPa and elongation of 15.2%. The strength level increased clearly as compared with pure aluminum and copper "sandwich" clad composite. (C) 2019 Elsevier B.V. All rights reserved.