Ballistic resistance of twisted bilayer graphene with interlayer sp3-bonding on SiC substrate

Abstract

Carbon occurs in various allotropes due to its bonding flexibility, including diamond-like structures formed by tuning the interlayer spacing of twisted bilayer graphene (TBG), which changes moiré pattern and the fraction of sp3-hybridized interlayer-bonded C atoms as well. Molecular dynamics simulation is employed to explore the ballistic performance of TBG with interlayer sp3-bonding on SiC. We find the specific penetration energy Ep* is kept high for diamond-like TBG with a high fraction of sp3 bonds at small twist angles, e.g., Ep* of SiC coated by diamond-like TBG structure (formed at the twist angle and interlayer spacing equaling 0.7° and 1.79 Å, respectively) is increased by 43.89% and 16.62% compared with bare SiC and bilayer-graphene-coated SiC at room temperature. The kinetic energy transferred to diamond-like TBG/SiC target is absorbed by (i) phase transition in the strike area and destruction until local penetration, (ii) folding deformation of diamond-like structure, and (iii) conic deformation of SiC substrate coupled/driven by the rapid propagation of cone wave in hard coating. Our studies uncover the dynamic protective mechanisms of TBG with interlayer sp3-bonding on SiC substrate, and shed light on the design of lightweight structures for coatings.