Improving interfacial strength of cold-rolled T2 copper/304 stainless steel thin laminates by ultra-fast electric pulse treatment

• Ultra-fast electric pulse treatment enhanced Cu/SS strips’ bonding strength and ductility while preserving tensile strength. • Unlike the uniformly heating heat treatment, electric pulse treatment combines localized thermal and athermal effects. • Electric pulse treatment produces an asymmetric structure with deformed SS grains and partially recrystallized Cu. Achieving a synergistic improvement in interfacial bonding and matrix strength in cold-rolled Cu/stainless steel (Cu/SS) thin strips remains challenging. Conventional heat treatment (HT) is limited by prolonged processing cycles and inevitable deterioration of the matrix strength. Although methods such as electric pulse treatment (EPT) offer higher efficiency, existing methods are mainly developed for thick plates, and their mechanisms for controlling microstructure and properties in thin composite strips are still not fully established. This study developed a fixture with vertically misaligned electrodes to deliver ultrafast, interface-focused EPT to mechanically bonded strips. Metallurgical bonding formed within seconds via rapid diffusion, while suppressing recrystallization in Cu and grain growth in SS. An asymmetric microstructure resulted: the SS side showed deformed matrix grains and interfacial nanocrystals, while the Cu side contained equiaxed fine matrix grains and ultrafine interfacial grains. After EPT at 18.3 A/mm 2 for 5 s, the peel strength reached 9.10 N/mm, corresponding to 23.3 and 15.2 times those of the as-rolled and HT states, respectively. The tensile strength remained 86.6% of the as-rolled value. This work provides an efficient strategy for producing Cu/SS thin strips with both high interfacial bonding strength and superior overall strength.