Nano-projectiles impact on graphene/SiC laminates

Abstract

The ballistic performance of graphene/silicon carbide laminates under nano-projectile impact is studied using molecular dynamics method, where graphene acts as a barrier coating for its unique intra-layer honeycomb-like structure and interlayer coupling effects. We reveal that under nano-indentation two-layer graphene with AB-stacking on 4H-silicon carbide(0001) exhibits the highest hardness, ∼ 140.06 GPa, comparable to diamond. During impact, the specific total penetration energy of laminates increases with the number of graphene layers n, though the partial of graphene decreases as n ≤ 3, which results from the van der Waals coupling effect of graphene on silicon carbide substrate. The ballistic limit velocity of silicon carbide coated by five-layer graphene is 69.4% higher than that of bare silicon carbide, leading to an increase of specific total penetration energy, ∼ 43.3%. It is interesting that the ballistic performance of two-layer graphene/silicon carbide is enhanced by the formed sp3 bonds and residual bending deformation under secondary impact (after the first low-velocity impact treatment), with the ballistic limit velocity and specific total penetration energy increased by 6.5% and 14.3%, respectively. Graphene is a promising coating that can preserve the functional integrity of materials underneath against hypervelocity impact.