Grain size effect on the mechanical properties of C7701/Ti/C7701 ultra-thin composite foils by influencing element diffusion

With the increasing application of titanium and copper alloy materials and various sandwich composites in various precision machining fields, it has become increasingly important to study the complex changes in the internal microstructure of sandwich composites and their influencing factors during the microforming process. In this study, titanium and C7701 foils were heat-treated at different temperatures to obtain raw materials with different grain sizes and microstructures. The heat-treated foils were rolled into a sandwich structure in a C7701 / Ti / C7701 arrangement and the composite foil was annealed at the same temperature. Metallographic and SEM tests on the composite foils showed that the titanium and C7701 rolled laminates were well bonded at 400℃ and 500℃ before rolling, and there was a certain gradient of elemental diffusion in the bonded layer, and the XRD test showed that a variety of intermetallic compounds were produced in the bonded layer. By analyzing the element diffusion and intermetallic compound generation at the interface of composite foils and conducting microtensile mechanical property tests on composite foils, it is found that the grain size before rolling the composite has an important influence on the interfacial bonding and element diffusion of composite foils, which in turn affects the mechanical properties of composite foils.