Atomic insight into the thermobaric effect of aluminized explosives

Abstract

The addition of active metallic particles to common explosives can greatly extend high-temperature and high-pressure time of explosion, as the so-called thermobaric effect. However, the atomic details for this effect remain unclear. This work presents an atomic insight into the thermobaric explosion including anaerobic and aerobic stages by molecular dynamics simulations with a thermobaric explosive (TBX) model consisting of Al@Al2O3 nanoparticle and RDX. It is found that the thermobaric effect is originated from the Al oxidation by the intermediates and products of the RDX decomposition in the first anaerobic stage with a lot of Al-O, Al-H, Al-C and Al-N bonds formed, and the further oxidation by O2 in the aerobic stage with many C, H and N atoms extruded from the Al clusters. Interestingly, in terms of the components and structures of the final products, as well as the total heat release, the whole thermobaric explosion of the RDX-Al system can be regarded as the sum of the RDX decomposition and the Al oxidation in O2. Thereby, the energy design of a TBX can be simplified by considering the sum of the decomposition heat of the energetic compound involved and the combustion heat of the active metal. Regarding RDX, it plays a role in forming a high temperature and high pressure environment to promote the dispersion and combustion of Al particles. This work presents the atomic details responsible for the thermobaric effect and it is expected to pave a way to understand this effect.

Keywords

• Thermobaric effect
• Aluminized explosives
• Molecular dynamics
• Combustion