Research on Cu/stainless steel composite thin strips by two-pass cold roll-bonding with intermediate annealing

Abstract

Abstract Roll-bonding is feasible to fabricate T2 copper (Cu)/ Stainless steel (SS) composite thin trips, which have great potential in micromanufacturing, robotics, aerospace, and other applications. However, the effective bonding of Cu and SS could be hindered by limited diffusion of the elements and uncoordinated deformation of the metal matrices. In this study, Cu/SS composite strips with 0.24mm thickness were prepared by the two-pass cold rolling process with intermediate annealing at 400 ~ 1000℃. The influences of the intermediate annealing process on the tensile and peeling strength were investigated. Finite element simulation and microstructure evaluation were carried out to analyze the deformation behaviors and bonding mechanisms of the strips. The results indicate that the deformation coordination in the second-pass rolling and the bonding strength were improved by appropriate intermediate annealing processes. The difference in the deformation resistance between Cu and SS became the lowest by intermediate annealing at 1000℃, while the deformation of Cu and SS was severely uncoordinated by annealing at 600℃. The peel strength and elongation of the strips annealed at 1000℃ were 11.65 ± 0.7N/mm and 34.8 ± 1.3% after the second-pass rolling, which were 79.23% and 6.64 times higher than the strips manufactured without intermediate annealing, respectively. In this work, Cu/SS thin strips with high bond strength and ductility were successfully manufactured by appropriate intermediate annealing process, and the bonding mechanisms were systematically discussed.