Thermal Decomposition Mechanism of β-HMX under Irradiation Damage Based on Molecular Dynamics Simulations

Energetic materials undergo chemical bond cleavage and structural reorganization under external stimuli such as heat and irradiation, leading to performance degradation or change. This study employs molecular dynamics simulations to investigate the atomic-scale mechanisms of irradiation-induced damage in β-HMX and its subsequent thermal decomposition mechanism. Results revealed that irradiation defects are primarily localized within collision cascade regions. Irradiation-generated nitrogen oxides and HNOx radicals provide new reaction sites during HMX thermal decomposition, significantly altering pyrolysis pathways and increasing the activation energy. Concurrently, irradiation-induced defects restructure the reaction network, modifying the propagation efficiency of radical chain reactions. This work provides atomic-level insights into the microscopic mechanism through which irradiation influences the thermal decomposition of HMX, offering a theoretical foundation for understanding the chemical evolution and stability of energetic materials under extreme conditions.