Damage and self-healing characteristics of monolayer graphene enhanced Cu under ballistic impact

Graphene has attracted great interest from both scientific and engineering fields in strengthening materials. However, there are still many unknown dynamic characteristics of graphene-reinforced nanomaterials under extreme conditions. Through in silico studies, this work carries out a systematic investigation on the damage process of monolayer graphene enhanced Cu under Cu ballistic impact. It is shown that graphene can effectively weaken the bullet penetration and promote the self-healing of impact crater and spallation damage. The damage in the Cu layers is dominated by plastic deformation and cratering, where both amorphization and recrystallization are observed after dislocation emission. It is important that the impact crater is finally restored to its original plane structure due to the presence of graphene. The graphene interface can prevent the mass flow forward and accelerate the energy delocalization. At the same time, the temporary spall at graphene/Cu interface occurs with the spatial deformation of graphene, and its self-healing process will also be completed as long as the graphene is not broken. For comparison, the rigid bullet is tested, which shows that the graphene can also improve the self-healing of the back Cu layers under certain impact conditions, although the whole sample is completely penetrated. All these findings shed lights on the development of impact resistant graphene composites.