Effect of continuous dynamic-recrystallisation on high-property multilayer Cu foils joint by friction-stir-welding

In this experiment, friction-stir-welding was proposed to research the flexible connection of multilayer Cu foils. It studies the correlation between hardness, conductivity, and continuous dynamic-recrystallisation. New grains of continuous dynamic-recrystallisation have a correlation between the dislocation density and the grain size, such that a lower dislocation density corresponds to a higher grain size and vice versa. It is shown that after friction-stir-welding of multilayer Cu foils, the hardness increases and the conductivity decreases due to the combined effect of fine grain strengthening and dislocation strengthening for new grains of continuous dynamic-recrystallisation of the weld zone. However, the hardness gradually decreases and conductivity gradually increases within the weld zone with continuous dynamic-recrystallisation degree.