Extremely high energy dissipation capability of the ion-irradiated CNT mats

Planar isotropic, highly porous multiwall carbon nanotube (MWCNT) mats were irradiated with high energy carbon ions to various doses to explore the effect of ion irradiation on high strain rate mechanical properties. The ions induce local bond damage as well as new covalent bonds within and between MWCNTs leading to additional deformation mechanisms beyond the localized tube-tube sliding and tension-failure modes of the pristine MWCNT mats. The energy dissipation capability of the ion-irradiated CNT mats was measured by laser-induced micro-projectile impact test (LIPIT) experiments. The specific penetration energy, Ep* increases over 200% compared to unirradiated mats, up to 28 MJ/kg, significantly higher than present armor materials. The post-mortem perforation morphologies were observed by scanning electron microscopy and show a relatively large network region around the impact site structure was cooperatively deformed, delocalizing, and dissipating the impact energy. Coarse-grained molecular dynamics (CGMD) simulations were also conducted to illuminate the influence of the structural changes from ion irradiation on MWCNT mat adiabatic heating effect after projectile impact. Simulations show higher adiabatic heating in the ion-irradiated MWCNT mats due to the extraordinary transfer of impact energy. Our present study provides an approach to improve the extreme rate dynamical performance of MWCNT mats.