Effect of heat treatment on the microstructure and mechanical properties of copper/SS304L composite sheets

Different annealing treatments at 400-900 °C for 1 h were applied on copper/SS304L composite sheets, and the evolutions of microstructure and mechanical properties were investigated in this study. It is found that the diffusion distance of the elements at the interface is slightly increased with the increasing temperature. In addition, the grain coarsening in copper, the phase transformation from BCC to FCC in SS304L, and the decreased dislocation density after annealing soften the composite sheets, leading to decreased hardness and strength, as well as significantly improved ductility, especially when the temperature exceeds 500 °C.