Optimization of intermediate annealing process for accumulative roll bonding copper-graphite composites

Copper-graphite composites prepared by traditional processes are prone to some defects, such as pores and cracks. Copper-graphite composites were prepared using accumulative roll bonding technology and an intermediate annealing process at different times. Their properties were characterized by XRD, SEM, EDS and other methods to determine the best intermediate annealing process. The results show that the fluidity of the material is improved with the increase in the number of intermediate annealing during the rolling process, which is beneficial for filling the pores between graphite particles and the copper matrix. During the annealing process, the recrystallization of the copper matrix occurs, which reduces the deformation resistance and the hardness, increases the relative density and the electrical conductivity, and improves the friction and wear performance. When the number of intermediate annealing decreases gradually, the wear amount of the composites increases gradually. Among them, the copper-graphite composite prepared by one-step annealing has the best comprehensive performance, with its relative density, electrical conductivity and friction coefficient reaching 97.9%, 94.5%IACS and 0.215, respectively.