Abstract:The research on the multi-scale structure and stimulation dynamic response mechanism of energetic materials has experimental diagnosis problems due to their heterogeneous characteristics and cross-spatiotemporal evolution， which restricts the in-depth scientific understanding of their safety and energy release characteristics. Large scientific devices represented by neutron sources， synchrotron radiation sources and large-scale lasers provide key means to solve the above problems by virtue of deep penetration， extreme loading conditions and high spatiotemporal resolution. The research progress of large scientific devices at home and abroad was reviewed in respect of the multi-scale microstructure， grain residual stress， impact loading physical properties， mesostructure evolution， detonation reaction characteristics， and etc. of energetic materials. The neutron scattering technology has realized the non-destructive quantitative characterization of the micro-nano structure and residual stress in the interior of explosives through its deep penetration characteristics and light element sensitivity. High-brilliance X-ray phase contrast imaging and dynamic X-ray diffraction technology revealed the dynamic evolution process of defects under shock loading with sub-micron resolution， and captured the detonation wave front structure and the dynamic characteristic of nano-carbon products in situ. By combining high-intensity laser loading with ultrafast spectroscopy technology， the Hugoniot data under high pressure and initiation reaction mechanism of explosives were obtained. In the future， it is necessary to develop multi-field coupled loading diagnosis platforms， to further improve the spatiotemporal resolutions of the devices， and to penetrate the data fusion analysis of multiple devices， which provide technical support for the understanding of dynamic-static safety and reaction characteristics of explosives， and for the structural design and performance improvement of explosives.

Abstract:As an emerging data-driven technology， machine learning provide a promising pathway for the intelligent research and development of energetic materials. However， data scarcity and heterogeneity have become the core bottleneck that restricts modeling accuracy and practical application. Focusing on the acquisition path and the existing of energetic material data， this review evaluates the mainstream data optimization strategies from two perspectives： quantity expansion and quality improvement. For data quantity expansion， recent advances in SMILES enumeration， generative adversarial networks， and transfer learning are introduced for enhancing model generalization ability. For data quality improvement， the roles of outlier detection， standardized preprocessing， and feature engineering in improving model robustness and interpretability are discussed. It is shown that effective data optimization can not only alleviate data limitations but also significantly enhance prediction stability and structural extrapolation capabilities under small-sample and structurally complex conditions. Finally， future directions are proposed， including the development of high-throughput experimental platforms， unification of data standards， and establishment of intelligent closed-loop systems. It is expected to provide a feasible roadmap and methodological reference for advancing the data ecosystem and intelligent design of energetic materials.

Abstract:Nitrogen-rich energetic compounds have received a lot of attention in the research fields of propellants， explosives and gas generant thanks to their high enthalpy of formation and clean decomposition products. However， as a significant branch of nitrogen-rich energetic materials， research and development on the compounds with all-nitrogen and chain-like nitrogen structures are hampered by the lack of suitable nitrogen sources and efficient synthetic methods for the construction of nitrogen chain backbone. In this review， the design ideas， synthetic methods， and breakthrough progress of all-nitrogen ionic energetic compounds and long nitrogen chains energetic materials containing at least six nitrogen atoms linked together are systematically analyzed， and the references for the design and development of milestone high energy density materials are offered.

Abstract:Hybrid rocket motor is a thermochemical propulsion method that stores different phases of fuel and oxidizer separately， which has the advantages of simple structure， low cost and adjustable thrust， making it possess wide applicability in military and commercial fields. However， the low regression rate and imbalance of mechanical properties restrict the development of hybrid rocket engines. This review summarizes the composition， combustion characteristics， laws and key technologies for improving combustion performance of typical hybrid rocket fuels， and analyzes the preparation methods and combustion performances of additive manufacturing fuels. Moreover， the future development directions and trends for advanced hybrid rocket motor fuels are also outlined， which provides insights and references for improving the performance of motors.

Abstract:The energy release law of gun propellants is one of the core and key factors determining the performance of barrel weapons， and the research on its control methods is of great significance. Based on the analysis of the propellant composition， structure and basic combustion law， the development and evolution of control methods for energy release law， such as geometry control， surface deterring and coating， and chemical molecule tailoring， were systematically summarized. Meanwhile， the control methods and technical characteristics of China''s independent innovation in recent years were analyzed， and the future directions of innovation and development were prospected. It is expected to provide reference and guidance for the research of gun propellants and charges applications in China.

Abstract:Due to the high energy density and excellent safety performance， high-energy low-sensitivity single-component explosive plays an crucial role in the national economy， military industry and aerospace sectors， and has become one of the key research topics in energetic materials. In recent years， scientists worldwide have carried out extensive studies on the creation of high-energy low-sensitivity single-component explosives. This article systematically reviews 27 types of single-component explosives reported since 2001， with detonation velocity above 8750 m·s^-1， impact sensitivity lower than 15 J， and thermal decomposition temperature greater than 200 ℃. These explosives fall into three major categories： single-ring， multi-ring， and fused-ring compounds. A detailed elaboration of the synthesis methods， structural features， and performance characteristics of these single-component explosives is provided， while an in-depth analysis of the challenges and bottlenecks encountered in the development is conducted. Based on current research advancements， this article outlines future development trends， emphasizing that molecular design capabilities should be enhanced according to practical needs. The specific attention should be paid to molecular defect recovery， the feasibility of synthetic processes， cost control， and the application of emerging technologies in this field.

Abstract:Small carboxylate molecules with flexible sequences typically exhibit characteristics such as insensitivity， low glass transition temperature （T_g）， available access， and good compatibility with solid propellant components. These traits make them ideal plasticizers for creating formulations featuring low-damage， low T_g， and highly adaptable. However， the absence of energetic groups results in low energy density， which limits the development of high-energy formulations. To address this problem， it is essential to incorporate the highly energetic， thermally and mechanically stable dinitro groups （─C─（NO₂）₂） into the structure. This incorporation must be carefully controlled in terms of the quantity and arrangement of （─C─（NO₂）₂）， the configuration of flexible alkyl sequences， and the segment length. Such meticulous design is crucial for creating ideal energetic plasticizers that effectively leverage the unique advantages of various functional groups. This investigation begins with an exploration of the molecular structure of nitro ester plasticizers. Meanwhile， how structural variations influence its performances and applications is thoroughly examined. Moreover， the structure-property relationship is also summarized. The model integrates machine-learning-enhanced molecular structure design， theoretical calculations with high-throughput preparation techniques， and engine formulation application testing， serving as a strategy for future research and development of the energetic plasticizers.

Abstract:Twin-screw extrusion technology， owing to its outstanding mixing capability， processing flexibility， and enhanced safety， has become a crucial driver in the continuous processing of energetic materials. This review summarizes recent advances in the use of twin-screw extrusion for the continuous manufacturing of energetic materials， particularly rocket propellants， gun propellants， and mixed explosives. It discusses the different types of twin-screw extrusion equipment， process design， and the advantages of modular configurations， particularly in terms of process adaptability and operational safety. International collaborations and successful industrial implementations， notably in the US， France， and the Netherlands， are outlined for continuous production of propellants and gun powders. Current challenges such as achieving fine and uniform processing， improving safety monitoring， and developing comprehensive theoretical models are analyzed. The future prospects of the technology for intelligent manufacturing and environmentally friendly processes in high-end energetic materials are also discussed. In summary， twin-screw extrusion provides a solid theoretical and practical foundation for efficient， automated， and innovative energetic materials processing.

Abstract:In response to the urgent demand for high-performance energetic material and in-situ integration method in microelectromechanical systems （MEMS） pyrotechnics， a safe and controllable electrochemical synthesis strategy was proposed for the in-situ growth of Cu₃Cl（N₄C-NO₂）₂ energetic metal complexes on a copper substrate surface. The influences of chloride ion concentration on the purity， crystal structure， and microstructure of the product were systematically investigated， and the phase morphology， energetic properties， and sensitivity of the energetic metal complex were comprehensively characterized. Results indicate that the chloride ion concentration significantly affects the phase composition of the energetic metal complexes. When the Cl^- concentration is 0.6 mol·L^-1， the high-purity and high-crystallinity Cu₃Cl（N₄C-NO₂）₂-0.6 energetic complex crystals are obtained. DSC analysis reveals a thermal decomposition peak at 301.7 ℃， with an exothermic heat of 1877.8 J·g^-1 and an apparent activation energy of approximately 157-159 kJ·mol^-1， demonstrating excellent thermal stability and energy release characteristics. Laser ignition experiments show that it possesses good detonation performance. Electrostatic sensitivity tests indicate that the in situ integrated energetic complex crystal films through electrochemical methods exhibit excellent electrostatic safety.

Abstract:Micro-nano composite energetic materials have attracted much attention due to their excellent properties and have broad application prospects in the fields of explosives and propellants. The electrostatic spray method， as an emerging composite material preparation technology， has a significant impact on the assembly and energy release regulation of energetic materials. To address the issues of insufficient combustion of micro aluminum powder， low energy release efficiency， and long ignition delay， the electrostatic spray method was used to successfully prepare uniformly mixed hexanitrohexacyclohexylazomethine/polyvinylidene fluoride/nanometer aluminum （CL-20/PVDF/nAl） based composite energetic microspheres. These microspheres were further modified with ferric oxide （Fe₂O₃） and reduced graphene oxide （rGO）. The results showed that the samples prepared by the electrostatic spray method had a regular morphology， uniform size， high sphericality， and a particle size of approximately 1-7 μm. Compared with the physical mixture samples， microspheres exhibit superior thermal and combustion properties. Additionally， the addition of oxidant Fe₂O₃ and catalyst rGO can significantly improve the energy release efficiency and combustion performance of the microspheres， and when the content reaches 20% and 4% respectively， the shortest combustion time is 7 ms， the minimum ignition delay time is 0.13 s， the maximum equilibrium pressure is 2.17 MPa， and the maximum pressure rise rate is 1.63×104 kPa·ms^-1.

Abstract:To investigate the impact of humid-thermal coupled environments on the structural stability of HNIW crystals and its underlying mechanism， accelerated aging tests， in-situ X-ray diffraction， and molecular dynamics simulations were employed to study the phase transition behavior of HNIW under various humid-thermal conditions and its intrinsic causes. It was found that the crystal transition temperature of HNIW in humid-thermal environments significantly decreased compared to that under thermal stimulation alone， dropping from 135 ℃ to 80 ℃. The particle size effect of HNIW led to multipath phase transition behaviors， namely ε→γ and ε→α， indicating that differences in crystal characteristics are key factors contributing to the multipath phase transitions in HNIW. Among these， the ε→γ transition rate was the fastest in ultrafine HNIW. Under humid-thermal conditions below 70% RH， the phase transition of HNIW was not significant， but microstructural damage resulted in reduced stability of the crystal phase structure and a decrease in the thermal crystal transition temperature. Combined with theoretical calculations， it is generally concluded that a hot and humid environment can induce liquid-solid interfacial reactions in HNIW. Water molecules， through a mechanism of surface micro-dissolution-induced nucleation and growth， promote the crystal form transformation of the explosive. This process leads to the embedding of water molecules into the internal structure of the HNIW crystal， resulting in the formation of the α crystal form. However， this embedding mechanism is selective； for ultra-fine particles， it directly induces transformation into the γ crystal form， which is stable at high temperatures.

Abstract:Based on the combination of simulation and experiment， the mechanical behavior of HMX-based granular in the mould pressing process was studied. The conventional charging model and jet charging model were constructed to elucidate the charge forming and crystal damage laws， and the molding pressure and density were experimentally verified. The results show that the increase of mould size leads to the decrease of stress transfer efficiency and significant increase of charge density gradient. The crystal damage rate of charges with diameter of 25 mm （13.94%） is nearly 3 times higher than that of charge with diameter of 10 mm （4.55%）. In the two-way pressing of jet charging， the symmetry of the load-displacement curves of the upper and lower indenters verifies the stress equilibrium transfer mechanism， and the simulation error of the side wall pressure （43.24 MPa） reveals the limitation of the spherical simplification of particles on the characterization of the friction effect. Through experimental verification， the simulation error of conventional charging density is less than 5%， and the prediction accuracy of axial pressure of jet charging is 94.3%， which confirms the reliability of the model.

Abstract:A comprehensive analysis platform of ReaxMDDB-EMs was developed for investigation of thermolysis reaction mechanisms across varied energetic compounds. An automatic data import program was implemented with a combined strategy of preprocessing and batch-import to solve the problem of unacceptable long time for dealing with massive data. Performance testing of the automatic data import program shows a 18-fold speed-up， which dramatically reduces the time to 26.8 hours for importing large volume reaction data set over one million species or reactions. The hierarchical functions developed for reaction analysis enable the unified retrieval， statistical analysis， and visualization of the massive reaction data collected in ReaxMDDB-EMs. The application of ReaxMDDB-EMs unravels the similarities and differences among the thermolysis of four nitramine energetic compounds， which indicates that the ReaxMDDB-EMs as a convenient tool allows for a comprehensive analysis of reaction mechanism within vast chemical space of thermolysis for energetic materials. This work provides an efficient tool for the new research paradigm of data-driven design of energetic materials on-demand in the big-data era.