Molecular Dynamics Insight into the Evolution of Al Nanoparticles in the Thermal Decomposition of Energetic Materials

It has become increasingly important to add Al nanoparticles (ANPs) into energetic materials (EMs) to overcome the issue of Al particles aggregation and promote the efficiency of heat release. Nevertheless, the underlying mechanism for the role of ANPs in EMs still remains limited. By means of reactive molecular dynamics simulations with the ReaxFF potential, the present work focuses upon the evolution of ANPs in a hot EM of 2,4,6-trinitro-1,3,5-triaminobenzene (TATB), which features very high insensitivity and O-lack. As a whole, adding ANPs unexceptionally increases heat release, and the morphological evolution of ANPs significantly depends on their sizes and contents, as the smaller size and the smaller content facilitate microexplosion. Moreover, a cracking of the core–shell structured Al@Al 2 O 3 is observed in the hot TATB, as in oxygen. Besides Al–O bonds, Al–C and Al–N bonds are formed owing to the O-poor character of TATB. In addition, fusion of four ANPs in a model is observed as the reaction proceeds. A hollow alumina sphere is formed when adding an Al@Al 2 O 3 particle to hot TATB, and it is found that there is an inward O transport and more O atoms concentrated around the center of an ANP with a relatively large size and high content. This work is expected to deepen insight into the complex reaction mechanism of ANPs-containing EMs.