Enhanced energy dissipation of graphene/Cu nanolaminates under extreme strain rate ballistic perforation

Dynamic deformations at extreme strain rates (>106/s) are frequently encountered by metallic structural materials. According to continuum theory, increasing the modulus and thus speed of sound in metallic materials could lead to enhanced impact resistance, while such goals are difficult to achieve via conventional alloying methods. On the other hand, recent researches have revealed that carbon materials such as graphene have far larger in-plane speed of sound than metals and therefore are intrinsically impact resistant. In this work, graphene/copper (Gr/Cu) nanolaminates were fabricated by incorporating graphene into copper matrix, and its ballistic performance at extreme strain rates (∼3 × 107 /s) was quantified via laser-induced projectile impact tests (LIPITs). The specific energy dissipation of Gr/Cu nanolaminates is found to be 54 % higher than Cu. Post-mortem analysis revealed that graphene nanoinclusions could cause additional coordinative deformation in regions surrounding the perforation zone in Gr/Cu, leading to enhanced ballistic performance of Gr/Cu nanolaminates.