Enhancing low-velocity impact energy release performance of PTFE/Mg/Bi₂O₃ reactive materials via constructing metal-oxide structure units

Control of component distribution is critical for optimizing the energy release behavior of reactive materials, particularly under low-velocity impact conditions. In this study, we propose three fabrication strategies, two-stage mixing, crushing-assembly, and Viton-assembly, to construct structured oxidizer-reductant (Mg/Bi₂O₃) structural units within PTFE/Mg/Bi₂O₃ reactive materials. A machine learning-based image analysis method was established to quantitatively evaluate the interfacial contact ratios between components. Compared to the one-pot method, the reactive material prepared by the Viton-assembly process exhibited a 35 % and 4 % increase in the effective PTFE-Mg interface contact ratio and Mg-Bi₂O₃ contact ratio, respectively, with a 40 % reduction in non-reactive PTFE-Bi₂O₃ contact. This optimized microstructure led to superior energy release performance, including a 217 % increase in impact flame intensity over the conventional one-pot method. Ballistic impact tests further demonstrated that the Viton-assembled reactive materials exhibited a 41 % enhancement in impact-induced energy release over the one-pot method under low-velocity conditions (∼470 m/s). These results demonstrate that modulation of component distribution is an effective strategy for enhancing reactive materials performance under low-velocity conditions.