The thermal decomposition behavior of the TNT‐RDX‐Al explosive by molecular kinetic simulation

The TNT‐RDX‐Al Explosive is an aluminum‐containing mixed explosive often used in civil and military equipment, but the decomposition mechanism has not been theoretically studied. In this paper, the reaction force field containing C/H/O/N/Al parameters was used to simulate the thermal decomposition of the TNT‐RDX‐Al Explosive by reaction kinetics simulation. And the results were compared with the thermal decomposition behaviors of the binary systems TNT/AlO RDX/AlO and TNT/RDX. The partially passivated nano‐aluminum particles were constructed and then mixed with TNT supercell, RDX supercell, and the constructed TNT/RDX supercell. The obtained mixed systems were then heated to a high temperature, where the explosive was completely decomposed. The decomposition process of the TNT‐RDX‐Al Explosive can be divided into several stages: the adsorption of aluminum atoms on TNT molecules and RDX molecules, the diffusion of O atoms into nano aluminum particles, the decomposition of TNT molecules and RDX molecules, the diffusion of C, H, N atoms into the nano aluminum particles, the Al atoms in the center of the aluminum sphere diffuse outward, and the final stage is the formation of the final product. The results show that the aluminum nanoparticles in the ternary system are easier to diffuse and spreads more widely. The addition of RDX molecules advances the time to complete decomposition of TNT molecules, and promotes the time when TNT molecules is completely decomposed to be closer to the time when RDX molecules is completely decomposed. The snapshot of the trajectories of aluminum‐containing clusters and carbon‐containing clusters in TNT/RDX/AlO and TNT/AlO systems at 3000 and 3500 K (The C atoms and Al atoms are in gray and green, respectively.) At high temperatures, the nano‐aluminum particles are easier to melt and disperse, promoting the transfer of O atoms and C atoms into the aluminum shell and avoids the formation of larger carbon clusters. The nano‐aluminum particles at 3500 K are distributed more widely than the carbon‐containing skeleton. And the addition of RDX makes the nano‐aluminum particles in the ternary system easier to disperse.