Chemical reaction mechanisms and models of energetic materials: A perspective

Energetic materials (EMs) are a kind of metastable functional materials with certain potential barriers, overcoming which can quickly release the energy stored in EMs. A thorough understanding of reaction mechanisms and accurate quantification of reaction rates are fundamental issues for optimizing energy output, ensuring hazard mitigation, and assessing the safety levels of EMs. This perspective provides an overview of research progress in chemical reaction mechanisms and models, with a particular emphasis on organic EMs and reactive metals. Organic EMs are mainly composed of carbon, hydrogen, nitrogen, and oxygen elements, enabling supersonic and self-sustaining detonation reactions capable of significant energy output. The incorporation of reactive metals like aluminum, magnesium, and boron has been recently found to augment the combustion heat and explosion temperature of EM formulations, sparking heightened research interest. This perspective first presents both EMs’ reaction mechanisms revealed via multiscale simulations and experimental methods, including thermal decomposition, shock initiation, and post combustion. Then, quantitatively characterized expressions of the physical models derived from the revealed mechanisms, including mathematical expressions like elementary and phenomenological reaction kinetic models, and emerging data-driven machine learning models, are reviewed. Finally, the view of the application, existing problems, and further development directions are outlined. • Microscopic mechanism decides macroscopic grade of energetic material reactions and can be described by proper models. • Due to resolution limits, experiments struggle to capture energetic material reactions, making computations essential. • Machine learning offers hope to break spatiotemporal limits of micro simulations, achieving creation of cross-scale models.