To study the fragmentation forming characteristics of 3D printed fragmentation warhead shells, a water medium fragmentation recovery experiment was conducted on the centrally pre-controlled channel steel shell melted by selective laser melting(SLM). By comparing the shell fragment forming conditions of different charge length to diameter ratios, pre-controlled groove depth ratios, and network shapes, the influence of pre-controlled groove parameters on the fragment morphology was clarified, and its fracture mode was discussed. The results indicate that the central pre-controlled grooves significantly improve the fragmentation controllability through directional guidance, achieving fragment mass recovery rates of 87.09%—94.42% and reach the maximum complete fragment generation rate of 99.60%. There is a critical threshold for the charge length to diameter ratio. When the length to diameter ratio of the charge was below 2.1, the complete fragment generation rate remained stable at 87.62% with theinter-connected fragments rate at 22.40%, whereas when it exceededg 2.1, the complete fragment generation rate drop sharply to 70.37% and the inter-connected fragments rate rise to 69.44%. Inter-connected fragment count exhibited a significant negative correlation with pre-controlled groove depth ratio η, while complete fragment generation rate increased markedly with higher η. Parallelogram and rhombus mesh shapes demonstrated superior fragmentation uniformity compared to the square meshes, with complete fragment generation rates of 96.09% and 99.60%, respectively. Fracture mode analysis revealed the tensile-dominated failure along the axial direction, shear failure at the inner circumferential wall, and tensile failure at the outer wall. When η exceeded 53.3%, the shear band width at the outer wall converged to match that of the inner wall.

To investigate the enhancement effects of free hydrogen produced by metal hydrides on the damage performance of fuel air explosive(FAE), A 20L spherical liquid explosion test system and the colorimetric temperature measurement technology were used to study the effects of different matrix liquid fuels and metal additives on the shock wave and thermal damage performance of FAE. The results show that epoxypropane(PO)has the best explosion performances of the three liquid matrix fuels commonly used in FAE. When titanium hydride(TiH₂)powders are added to PO, the explosion overpressure, maximum pressure rise rate and maximum average temperature of the mixed fuels increase first and then decrease with the increase of TiH₂ powders content, reaching the maximum values when the mass fraction of TiH₂ powders was 35%, namely, 1.21MPa, 68.73MPa/s and 2398K, respectively. Compare to Ti-PO mixed fuels, the TiH₂-PO mixed fuels has more continuous combustion flame and more excellent explosion performances at the same mass concentration. The research results indicate that as a potential high-energy additives, TiH₂ could be effectively applied to FAE to improve its explosion characteristics and enhance the shock wave as well as the thermal damage performances.

Regarding the problem of insufficientfire transfer rate of black powder, the nano-sulphur/RGO composite(RGS)wasprepared based on growth of nano-S on RGO in-situ, then mixed with KNO₃using ice template method to get KNO₃/RGS composite(RGPS). The morphology, composition, thermal decomposition and combustion performance were characterized by FE-SEM, XRD, BET, DSC and HSVR and the performances of KNO₃/RGS composite(RGPS)were compared with that of the physical mixture. The results show that nano-S is anchored in situ on RGO nanosheets and KNO₃ is embedded in RGS. The average diameter of the size of KNO₃ is about 3μm. The BET surface area of RGPS composite is about 8.1m²/g, which is much larger than 4.2m²/g of the physical mixture. The exothermic peak temperature of RGPS is lower about 13.6℃ than that of the physical mixture, the amount of released heat increased by 82.4%. The reaction activation energy of RGPS composite is 153kJ/mol, reduced by 16kJ/mol compared to the physical mixture. Compared with black powder physical mixture and RGPS physical mixture, the average combustion speed of RGPS composite is increased by 220.3% and 182.1%, respectively. The strategy can enhance the thermal decomposition and combustion performance of RGPS.

In order to study the ignition and explosion properties of micro-nano self-assembled and physically mixed aluminum powder materials, the ignition sensitivity, flame propagation characteristics and explosion parameters of the materials were studied through a 1.2L Hartmann tube and a 20L ball explosion test system. The results show that compared with Al-T4 micron aluminum powder, nano-aluminum powder can significantly reduce the ignition energy of aluminum powder materials.And the ignition sensitivity of the self-assembly process is further increased compared with that of aluminum powder materials with physical mixed process. In terms of the flame propagation speed, the high reaction rate of a small amount of nano-aluminum powder can accelerate the reaction of micron aluminum powder, and the self-assembled aluminum powder is easy to ignite and the heat transfer is more efficient due to the overall synergistic effect of micro-nano aluminum powder. In the 20L ball explosion test system, the maximum explosion pressure and explosion index of self-assembled and physical mixed aluminum powder with 5% mass fraction of nano content are 0.72MPa, 0.75MPa, 43.21MPa·m/s and 31.49MPa·m/s at 500g/m³. The maximum explosion pressure and explosion index of self-assembled and physical mixed aluminum powder with 10% mass fraction are 0.84 and 0.68MPa at 1000g/m³. The explosion pressure and explosion index of 5% mass fraction of nano aluminum powder increase first and then decrease with increasing the concentration, and the explosion pressure and explosion index of aluminum powder with 10% mass fraction increase with the increase of concentration. The explosion power of the composite system isnot only related to the activity, but also has a certain relationship with the calorific value of the powder.

In view of the poor description of 2,6-diamino-3,5-dinitropyrazine-1-oxide(LLM-105)by the ReaxFF initial force field, a JAX-ReaxFF framework strategy based on the gradient descent algorithm was adopted to reparameterize the ReaxFF reactive force field, paying much attention to the dissociation changes of the potential energy surface of different bonds and bond angles. The reaction mechanism of LLM-105 was analyzed in the simulation of reactions at different temperatures and thermal decomposition rates. The results indicate that at 1500 K, the molecular reactions mainly involved polymerization and dehydrogenation. As the temperature gradually increased, the reaction pathways of LLM-105 showed new changes. When the temperature is not less than 2000K, in addition to the original polymerization and dehydrogenation reactions, the cleavage of C—NO₂ bonds and C—NH₂ bonds were also observed. It is worth noting that the C—NO₂ bond became the key factor in triggering this series of reactions. As the C—NO₂ and C—NH₂ bonds in the molecules began to undergo homolytic cleavage, the formation of intermediates HON₂, NO₂ and NH₃ were formed. These intermediates underwent complex interactions and eventually generated stable products such as N₂, H₂O and CO₂, indicating that the force field can effectively simulate the changes in chemical reactions at different temperatures and heating rates.

In order to investigate the plasma characteristics and evolution of nitrogen-containing compounds generated by pulsed laser ablation in different atmospheric environments, by using boron nitride(BN)as the target material, it was ablated by pulsed laser in nitrogen, air, and near-vacuum, respectively. The plasma signals generated by ablation with different delay times were collected by spectrometer, revealing the growth and extinction processes of plasma. The results show that the BN ablated in air generates a large amount of oxygen plasma and exhibits a characteristic spectral peak, which essentially disappears when ablating in nitrogen or near vacuum. When BN is ablated in nitrogen, the higher number of nitrogen atoms(N I), monovalent nitrogen ions(N II)and trivalent nitrogen ions(N IV)are generated, and the nitrogen plasma exists for the longest time. For N I and N IV the longest existence time are up to 4400ns and 3450ns, respectively. Laser ablation of BN in nitrogen is the most favorable for the preparation of nitrogen atom clusters under the three different sputtering environments.

The applications of biomolecules such as DNA, peptides, proteins, polydopamine(PDA), tannic acid(TA)and cellulose in the field of energetic materials were reviewed. Firstly, the current problems faced by conventional energetic materials were analyzed, and the advantages of self-assembly technology in the preparation of new structural energetic materials were presented. The new structural energetic materials prepared with self-assembly technology by assembling biomolecules were expected to realize improvement in performance. Then, based on relevant studies at home and abroad, the structural features of these biomolecules, the advantages, process and mechanism of assembly were described. The performances of the synthesized new structural energetic materials were also outlined. Finally, the current research on the applications of biomolecules in the field of energetic material were summarized. The challenges faced by the new structural energetic materials in terms of performance optimization, mechanism study and application cost were analyzed. Their potential applications in aerospace and sustainable development were looked forward. 55 References are attached.

In order to promote the green development of industrial explosives, the green oxidant hydrogen peroxide(H₂O₂)is used to partially or completely replace ammonium nitrate(AN)to form a new type of industrial explosive. This can reduce the generation of NO_x and improve the adverse impact on the environment. It is the most promising industrial “green explosive”. Based on this, the research progress of H₂O₂-based mixed explosives was reviewed, and the detonation performance of H₂O₂-based explosives was introduced from three aspects: H₂O₂/H₂O pure solution, H₂O₂/Fuel liquid mixture and H₂O₂/Fuel colloid. The decomposition characteristics of H₂O₂ in H₂O₂/Fuel-based explosives were analyzed, and the detonation performance of H₂O₂/Fuel-based explosives was compared with that of traditional AN-based explosives. The shock initiation mechanism of H₂O₂-based explosives was explained. By elaborating on the progress in research on the explosiveness of H₂O₂-based explosives, the problems faced by H₂O₂-based “green explosives” were analyzed, including insufficient basic performance characterization and unclear initiation mechanism, and the development prospects of H₂O₂ in industrial explosives were prospected. 103 References are attached.

In order to study the ignition response characteristics of HTPB propellant slurry with high burning rate under heat and low speed impact stimulation, two kinds of high burning rate propellant slurry(gas contents were 1.6% and 0.3%, respectively)and two kinds of high burning rate propellant(burning rates were 35mm/s and 5mm/s, respectively)were prepared. The experiments were carried out by self-made heating device, Separated Hopkinson Pressure Bar(SHPB)and drop hammer impact equipments. The ignition response characteristics of propellant and slurry under thermal and low-speed impacts were analyzed by means of synchronous thermal analysis infrared spectroscopy, micro-CT scanning and high-speed photography. The results show that the thermal ignition temperature of the propellant with high burning rate(241.6℃)is significantly lower than that of the slurry, and the thermal ignition temperature of the slurry presents a small positive correlation with gas content(thermal ignition temperature of the slurry with gas content of 1.6% and 0.3% are 261.3℃ and 255.7℃, respectively).The impact ignition threshold of the slurry with high burning rate is significantly affected by the gas content and restraint mode. In the SHPB impact test without radial constraint, the ignition threshold of the slurry is positively correlated with the gas content(ignition thresholds of the slurry with 1.6% and 0.3% gas content are 71J and 33J, respectively), indicating that the slurry with high gas content is not easy to be impacted and ignited. In the drop hammer test with radial constraints, the ignition threshold of slurry is negatively correlated with the gas content(the ignition threshold of slurry with gas content of 1.6% and 0.3% are 7J and 9J, respectively), indicating that when slurry with high gas content impacts, it is more likely to impact and ignite.

To study the effect of metal wires on the burning rate of solid rocket motor grain, six materials wires with superior thermal conductive and mechanical properties were selected and embedded into HTPB to conduct ignition tests. The relationship between the materials' burning rate enhancement ratio and tensile strength, and the effect of pressure on the burning rate enhancement ratio were analyzed, a transient analysis of the burning rate enhancement ratio based on heat transfer theory and burning surface back-calculation was conducted, and a comparative analysis on the impact of different materials property parameters on the burning rate enhancement ratio was carried out. The results indicate that the tensile strengths of the copper-silver and silver-nickel alloys are found to be 2.1 times and 3.6 times that of pure silver, the burning rate enhancement ratio at 94% and 43% of pure silver, respectively, the alloys have a more balanced performance combination of burning rate enhancement ratio and strength. When the average pressure increases from 3.8MPa to 9.1MPa, the max burning rate enhancement ratio of the silver-nickel alloy increases from 2.5 to 2.8. Under high pressure, the burning rate enhancement ratio increases from 0 to the maximum of 3.25, then decreases to 2.65 and stabilized, showing large fluctuations in the burning rate enhancement ratio. In contrast, under low pressure, there is hardly any rising or falling trend, leading to a more stable burning rate enhancement effect, which better match the theoretical analysis. The melting points and specific heat capacities of different materials are negatively correlated with the burning rate enhancement ratio, while the thermal conductivity shows a positive correlation.

In order to improve the combustion performance and iodine content of high-energy bactericidal films, several Al/Ca(IO₃)₂/PVDF laminated films(3, 5, 7 and 9 layers)packaging 39% Al/Ca(IO₃)/(5% or 10%)PVDF thermite(5PVDF or 10PVDF)were designed and prepared. The influence of the thermite reactivity(5PVDF or 10PVDF)and its distribution structure(multilayers and thickness)on the reaction temperature, energy release, combustion performance and mechanism of the laminated films were studied by DSC-TG analysis, burning rate and flame temperature tests. Furthermore, the reaction temperature and mechanism between each component of the laminated film were determined. The results show that laminated films encapsulating 39% 5PVDF thermite exhibits 18%—35% higher burning rate than that of packaging 10PVDF thermite. Especially, the laminated films with 5 layers display the highest burning rates of 10.2cm/s and 8.6cm/s, respectively, which combines the effects of the thickness and low burning rate of the 30PVDF layer, the mass and heat transfer efficiency of the film-thermite layer at the interface. Moreover, the average flame temperature of the laminated films increase with the decrease of the thickness of the thermite. DSC-TG results indicate that the Al/Ca(IO₃)₂/PVDF-based laminated films exhibit the exothermic iodine release reaction zone of Al-Ca(IO₃)₂-PVDF at 330—410℃. The Ca(IO₃)₂/PVDF at a mass ratio of 1.55:1 exhibits an intense exothermic reaction at 320—350℃, while the AlF₃, CaF₂, CaO, etc are determined in combustion products, which both suggests the reaction path of Al-Ca(IO₃)₂-PVDF. The study preliminarily reveals the combustion law and mechanism of Al/Ca(IO₃)₂/PVDF-based laminated films sandwiching thermite, providing a new technological solution for sterilization of high-energy materials.

From the perspectives of reducing the influence of external stimuli and optimizing the structural design of energetic materials, the desensitization mechanisms of single compound energetic materials under different desensitization strategies are reviewed, including buffering, lubrication, conduction, heat absorption and insulation, improving the quality of energetic crystals and enhancing the stability of energetic molecules. The comprehensive desensitization mechanisms of multi-dimensional desensitization strategies such as using multifunctional desensitization materials and coupling various desensitization means are analyzed. The development directions of desensitization of energetic materials in the future are put forward: to develop energetic materials with both high-energy and insensitive characteristics, to research the relationship between desensitization mechanism of energetic materials and operational environment, and to build up universal quantitative description models of sensitivity from the molecular scale, providing theoretical guidance and technical support for designing new high-energy insensitive energetic materials. 93 References were attached.

The mechanical properties of solid propellants under different aging times were tested through accelerated aging storage tests. The results showed that with the extension of aging time, the modulus and elongation of the propellant decreased, indicating a deteriorating trend in the mechanical properties of the propellant. In order to further reveal the reasons for the deterioration of the mechanical properties of propellants, CL-20/HMX eutectic was prepared by solvent method, and the eutectic phenomenon of CL-20 and HMX in nitrate ester system was studied; The morphology, structure, and thermal properties of the eutectic were characterized using field emission scanning electron microscopy(FE-SEM), X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), and thermal analysis; A new crystal was extracted from the aged surface of the propellant using a separation method, and its structure was verified using SEM, XRD, and FTIR. The results showed that the crystal structure of CL-20 and HMX did not change after dissolution in nitrate ester adhesive, but during the high-temperature accelerated aging process, CL-20 and HMX formed eutectic.

The absorption between nitroguanidine crystal surfaces and polyvinyl alcohol(PVA)solutions at various concentrations was simulated by molecular dynamics based on the interaction model for nitroguanidine and polyvinyl alcohol solution(NQ-sPVA model). The optimal process concentration of the PVA solution is determined. The gas generator samples were produced, and their combustion performances were subsequently examined. The force field model was optimized based on the parametric error between theoretical structures and single crystal diffraction analysis of nitroguanidine. The potential function was utilized to calculate the interfacial energies, integrated interface energies, and modified attachment energies between the PVA solution and the nitroguanidine crystal surfaces using the MAE model. SEM and densitometer were used to investigate the influence of PVA solution concentration on the process quality of gas generator tablets. The combustion performances of gas generator tablets were tested by the closed combustion chamber. The results show that the COMPASS II force field is most suitable for this research system because of its minimum error. The optimal process concentration of PVA to water is 1:3.75 in mass ratio, which allows for easier absorption by the nitroguanidine crystal with the lowest integrated interface energy of 0.33kJ/(mol·Å²). Moreover, the modified attachment energies of the surfaces(2 2 0),(0 4 0),(1 1 -1), and(1 1 1)of the nitroguanidine crystal coated with PVA solutions are -448.99, -548.40, -553.33, and -574.80kJ/mol, respectively. As a result, the divergence in the growth rate of the nitroguanidine crystal surfaces during recrystallization is minimized, thus improving the coating effect. Additionally, the gas generator particles produced at the optimal concentration have fewer surface defects. The compressed tablets exhibit a high consistency in thickness, weight, and density, as well as excellent combustion stability. Above all, optimizing the binder's process concentration is an effective method to improve the process quality and combustion stability of the gas generators.

In order to improve the safety performance of HMX, HMX/FOX-7 nano-cocrystals with different molar ratios were prepared by the ultra-low-temperature-assisted recrystallization method, where FOX-7 with low sensitivity was used as another component of the binary cocrystal. The morphology, structure, and thermal properties of the prepared HMX/FOX-7 cocrystals were characterized by SEM, XRD, FT-IR and DSC-TG, and their mechanical sensitivities were analyzed. The results show that the prepared HMX/FOX-7 crystals are mainly porous structure stacked with spherical particles, and their particle sizes are distributed primarily in the range of 0.1—0.5μm. During the formation of HMX/FOX-7 nano-cocrystals, the “low-temperature freezing” of the HMX/FOX-7 solution from liquid nitrogen and the formation of hydrogen bonding among HMX and FOX-7 have an significant influence on the formation of HMX/FOX-7 nano-cocrystals. The apparent thermal decomposition enthalpies of HMX/FOX-7 nanocrystals is significantly higher than that of the raw HMX and FOX-7, and increases with the increase of HMX content. The mechanical sensitivity of each HMX/FOX-7 nano-cocrystal is substantially reduced compared with that of the raw HMX. When the molar ratio of HMX and FOX-7 is 1:3, the prepared HMX/FOX-7 cocrystal has the lowest mechanical sensitivity, where the impact sensitivity is higher than 45J and the friction sensitivity is 288N.

Ag/g-C₃N₄ photocatalyst was synthesized using self-made zinc nitrate-containing deep eutectic solvent(nitro-DES)as nitrating agent. Utilizing the Ag/g-C₃N₄ as photocatalyst, dinitroanisole(DNAN)was successfully synthesized from the nitration of anisole under a mild and non-acidic process. The photocatalyst Ag/g-C₃N₄ was characterized using X-ray powder diffraction(XRD), ultraviolet-visible diffuse reflectance spectroscopy(UV-vis DRS), infrared spectroscopy(IR), scanning electron microscopy(SEM), transmission electron microscopy(TEM)and energy-dispersive X-ray spectroscopy(EDX)analysis. The photocatalytic nitration mechanism of dinitroanisole(DNAN)was predicted. Results show that a low-melting, transparent and polar nitro-DES can be formed spontaneously, which is composed of zinc nitrate and choline chloride in equimolar proportions. It can be not only favored for the absorption and propagation of visible-light but also serve as a nitro source in the nitration reaction. The doping of noble metals is observed to remarkably improve the photocatalytic efficiency of C₃N₄. Using xenon lamp to simulate the sunlight irradiation, the conversion of anisole to DNAN is above 90% within a period of 3h at a temperature of 55℃. The inhibition experiments suggest that the mechanism of photo-driven nitration can be involved with the nitroxyl radicals.

To explore the nucleation process of hexanitrohexaazaisowurtzitane(CL-20)/1-methyl-3,4,5-trinitropyrazole(MTNP)cocrystal,a comparative study was conducted on the solubility and metastable zone width(MSZW)of the CL-20/MTNP cocrystal and its co-formers in ethanol. And a modified Sangwal model was applied to further analyze their nucleation behaviors. The results show that the MSZW decreases with increasing saturation temperature(T_s)and decreasing cooling rate(q), and q has a more pronounced effect on the MSZW at higher q values. Furthermore, the interfacial energy(γ)and nucleation kinetic factor(A)of all three substances decrease with increasing T_s, which suggests that higher T_s is beneficial to nucleation. The CL-20/MTNP cocrystal exhibits the highest γ, critical nucleus radius(r_crit), and Gibbs free energy(ΔG_crit)along with the lowest A, resulting in the widest MSZW and the most challenging nucleation. In contrast, MTNP exhibits the lowest γ, r_crit, and ΔG_crit as well as the highest A, leading to the narrowest MSZW and the easiest nucleation. The case of CL-20 has fallen in between.

In order to reveal the composition-structure-sensitivity relationship of energetic crystalline materials, the influence of crystal characteristics, namely, the crystal structure, crystal morphology, multi-component crystal composition and composite structure, as well as test conditions and sample state on impact sensitivity, were systematically studied and summarized and the basic reasons were explored. The influence of crystal morphology, grain size, defects and aggregation structure on impact sensitivity is mainly of macroscopic or qualitative, where the limit of influence and quantitative relationship of crystal characteristics on impact sensitivity are unclear. The construction mechanism of cocrystallization, doping and coating of multicomponent composite crystals is unclear, and the qualitative and quantitative relationship between composition and structure and sensitivity is not established yet. The mechanism of the different crystal characteristics on impact sensitivity has not reached a unified understanding. On this basis, the strategies were proposed to reduce impact sensitivity from three aspects: crystal structure design, crystal particle morphology control, composite crystal design and preparation technology, which will provide a guidance and reference for the design and application of high-energy and low-sensitivity energetic materials. 128 References were attached.

Aiming at the pyrolysis combustion process of the pasty propellant nearing the burning surface, laser ignition experiment of the pasty propellant were carried out, at the same time, based on the multiphase chemical reaction numerical solver independently developed by the research group, combined with the 14 component 14 elementary chemical reaction equation, a detailed investigationwas conducted on the pyrolysis and combustion characteristics of the pasty propellant in the near burning surface region. The macroscopic structure of propellant combustion flame was obtained through experiments and the burning rate of the pasty propellant was measured under constant pressure conditions. The fitted burning rate curve was in good agreement with the experimental results, indicating good predictive ability of the burning rate of the pasty propellant under the experimental pressure range in the combustion chamber of the rocket engine. The combustion flame structure and chemical reaction sequence of the pasty propellant under constant pressure conditions were analyzed through numerical calculations. The effects of different environmental pressures on the combustion process of the pasty propellant were also calculated. The results showed that the first reaction that occurred during the pasty propellant combustion was the decomposition of AP, while higher environmental pressures limited the diffusion of primary combustion gases, but enhanced the thermal feedback effect on the pasty domain, which improved the burning rate of the pasty propellant.

For a better understanding of the reactivity of aluminum-lithium alloys, this study analyzed the oxidation characteristics and kinetic parameters of aluminum-lithium alloys using TG-DSC. The combustion process and the combustion products were analyzed using a self-designed setup, SEM, XRD, and other equipments. The effects of different oxidizers on the alloy's reactivity were also compared. The experimental results revealed that the oxidation of aluminum-lithium alloys occurred in three stages: the first stage from the beginning up to around 800 K, the second stage at 800-1100 K, and the third stage at temperatures above 1100 K. Furthermore, the apparent activation energy of the alloy's reaction in air and oxygen environments was calculated using the Kissinger, Ozawa, and Friedman methods. Compared to ammonium perchlorate, polytetrafluoroethylene (PTFE) demonstrated better promotion of the aluminum-lithium alloy's reaction. When the aluminum-lithium alloy/PTFE was heated in air, a vigorous oxidation process was immediately observed after the melting of aluminum. When the aluminum-lithium alloy/PTFE was combusted in air, it exhibited a larger gas-phase flame and more intense combustion process compared to aluminum-lithium alloy/ammonium perchlorate. The aluminum in the alloy exhibited higher combustion efficiency, leading to more complete reactions

The influencing factors of fracture properties of solid propellant were summarized, and the research status of fracture properties and crack propagation of solid propellant was reviewed; The common numerical simulation methods for simulating propellant fracture and crack propagation were introduced; The research on solid propellant fracture was prospected. It was considered that the research on dynamic fracture considering the influence factors of thermodynamic coupling, fracture performance in combustion environment, real-time microscopic observation of the whole process under dynamic loading and the update of numerical simulation methods will be the focus of the future research on solid propellant fracture and crack propagation with 75 references.

Carbon nanofibers(CNFs)are introduced into the nitroguanidine gun propellant system to investigate its effects on structure and properties of the gun propellant. The structure and composition of the sample are characterized by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR)and Raman spectroscopy(Raman). Differential scanning calorimetry(DSC)is used to analyze the thermal decomposition behavior and kinetics of the propellant by the Kissinger and the Ozawa methods. The effect of CNFs on the combustion performance of nitroguanidine gun propellant is studied by closed bomb test, and the impact strength tests are carried out. The results show that the structure of nitroguanidine gun propellant modified by CNFs is stable. Compared with the blank sample, the activation energy(E_a)of thermal decomposition of the gun propellant sample containing 1%(mass fraction)CNFs increases from 200.62kJ/mol to 208.65kJ/mol, reflecting the improvement of thermal stability. The gun propellant containing CNFs can burn steadily and appropriate amount of CNFs have a good regulatory effect on its combustion process. In addition, adding appropriate amount of CNFs can effectively improve the impact strength of the propellant. The impact strength of the sample with 0.5% CNFs is improved by 26.03% compared with the blank sample at low temperature.

In order to study the heat-induced damage evolution of GAP/AP/RDX/Al composite solid propellants under heating conditions, two GAP-based propellants with different RDX/AP contents were prepared, and the thermal decomposition properties of the samples were characterized by TG-DSC-IR technology. The samples were heated with a heating device, and the CT profile image, 3D pore distribution map, porosity and pore size distribution of the two propellant samples were obtained under different heating temperatures(50—130℃), heating times(5—35min)and heating areas(25%, 50% and 87.5% surface area)through micro-CT imaging and three-dimensional reconstruction of scanning images. The results show that the pores in the initial sample of GAP propellant are mainly the initial pores inside solid particles such as AP and RDX, and the thermal damage pores are mainly the interface dewedding pores between solid particles and the adhesive matrix, the pores generated after the matrix decomposition, and the initial structural defects. The pore damage size of GAP propellant after heating at 130℃ increases significantly compared with the initial sample, and the higher the RDX content, the greater the damage degree of the sample after thermal stimulation.

Aiming at the pyrolysis and combustion process of the near burning surface of the pasty propellant, the laser ignition combustion experiment of the pasty propellant were carried out. At the same time, the pyrolysis and combustion characteristics of the near burning surface region of the pasty propellant were studied based on the multiphase chemical reaction numerical solver developed by the research group and the 14-component and 14-primitive chemical reaction equation. The macroscopic structure of propellant combustion flame was obtained through experiments and the burning rate of the pasty propellant was measured under constant pressure conditions. The combustion flame structure and chemical reaction sequence of the pasty propellant under constant pressure conditions were analyzed by numerical calculations. The effects of different ambient pressure on the combustion process of the pasty propellant were calculated. The results show that the fitted burning rate curve was in good agreement with the experimental results. In the range of experimental pressure, the burning rate of propellant in the combustion chamber of pasty rocket engine could be predicted well. The decomposition of AP is the first reaction in the combustion of pasty propellant, and the higher ambient pressure limited the diffusion of primary combustion gases, but enhanced the thermal feedback effect on the pasty domain, which increased the burning rate of the pasty propellant.

In order to study the influence of stretching process parameters on the safety performance of modified double base propellant molding process, the compression melting section, melt conveying section and die forming section are modeled as a whole, the density, rheological properties of the modified double base propellant slurry are determined, the mesh independence of the fluid domain is verified based on Polyflow software, and the safety characteristics of the stretch molding process of the modified double base propellant slurry under non-isothermal conditions are studied. The results show that the increase of screw speed increases the temperature, pressure and shear rate of the slurry, and there is a risk of ignition and explosion, in order to ensure the safety, the appropriate screw speed in the stretching molding process is 10r/min. With the increase of screw temperature, the shear rate decreases, the plasticization degree of the material becomes worse, and the increase of screw temperature is easy to decompose the material, combined with the composition characteristics of the sensitive material of modified double base propellant, the screw temperature is relatively safe at 85℃. Compared with the screw temperature, the change of sleeve temperature has little influence on the material flow field, and combined with the actual production conditions of modified double base propellant, the sleeve holding temperature of 70℃ is suitable for the production of modified double base propellant. Based on the simulation results, it is concluded that the effects of rapid changes in pressure and temperature should be paid attention to in the propellant production process.

To investigate the effects of metal fuels on the reactions of ammonium perchlorate(AP)oxidizer in propulsion systems, the energy release processes and reaction characteristics of two aluminum-based metal fuels, namely Al-Li alloy and Al-Mg alloy, were analyzed by TG-DSC, SEM, XRD, and a custom-designed combustion apparatus. The apparent activation energy was calculated by Kissinger method. The results reveals that the Al-Li alloy exhibits inhibitory effects on both the low-temperature and high-temperature decomposition stages of AP, which elevates decomposition peak temperatures for both stages. In contrast, the Al-Mg alloy has a strong promoting effect on the low-temperature decomposition stage of AP, lowering the decomposition peak temperature to 287.3℃. The addition of Al-Li alloy results in an apparent activation energy of 129.7kJ/mol for the first decomposition stage of AP and approximately 247.0kJ/mol for the second stage. Conversely, the addition of Al-Mg alloy leads to a negative apparent activation energy(-207.2kJ/mol)for the first decomposition stage of AP. Additionally, in the Al-Mg alloy/AP system, a vigorous decomposition of AP is observed, accompanied by the generation of a prominent gaseous flame during sample combustion. In this process, aluminum and magnesium are nearly fully consumed. However, in the Al-Li alloy/AP system, aluminum is still detected among the combustion products.

The random packing structures of five types of explosive molding granular samples were investigated using X-ray microtomography to obtain the parameters, including granule spatial arrangement, packing characteristics, and granule contact features. The results show that the random packing system of molding granules exhibits a certain degree of size segregation, with larger granules tending to distribute at the bottom of the container. The filling process affects the horizontal orientation of granule distribution. The average packing efficiency of each sample varies continuously as granular radial distance increases, indicating a long-range disorder in the random packing structure of the molding granules. The average contact number of the samples is 5—6, suggesting a random loose packing of spherical granules. However, due to the impact of the radius and morphologies, the volume fraction of granular random packing systems can exceed the limit of random close packing for spherical granules(0.64).The particles formed by the packing system of molding granules in local contact are unevenly distributed in terms of quantity, size, and morphology, but the contact angle around 60° is the most frequent among various contact structures, forming a contact angle distribution with a single characteristic peak around 60°.

Aiming at the problem of poor safety of hexanitrohexaazaisowurtzitane(CL-20), the work of compounding two high-energy components of CL-20 and Al powder was carried out based on the Pickering emulsion method. The energetic binder nitrated bacterial cellulose(NBC)was introduced to reduce the sensitivity of the system, and the CL-20-NBC/Al spherical complexes was prepared. The effects of oil-water ratio, material ratio, and surfactant dosage on the stability of the emulsion were investigated. And the structure, morphology, and thermal properties of the CL-20-NBC/Al composite energy-containing materials were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), and differential scanning calorimetry(DSC). The results show that the CL-20-NBC/Al complexes prepared by Pickering emulsion can form a stable emulsion system when the oil-water ratio is controlled to be 4/6, the ratio of raw material CL-20/NBC to be 4/6, and the amount of surfactant to be 10% of the raw material. The prepared CL-20-NBC/Al composite is a regular sphere with a smooth surface and a particle size distribution D₅₀ of 27.4μm. At the same time, compared with the raw material CL-20, the heat release of CL-20-NBC/Al composites increases by 42%. The characteristic drop height increases from 13cm to 40cm. The explosion probability of friction sensitivity decreases from 100% to 88%, and the mechanical safety performance is greatly improved.

Molecular perovskite energetic material DAP-4 was synthesized by chemical methods, and it was characterized by using SEM, EDS, XRD, IR, XPS, and elemental analysis. The enthalpy of formation(ΔH_f)and the thermal decomposition performance of DAP-4 were tested by using the oxygen bomb calorimeter and DSC technology. Its mechanical sensitivity, detonation performance, and combustion performance were also carried out. The DAP-4 was used in CMDB propellant, and the constant volume combustion and the constant pressure combustion performance were tested. The results show that the enthalpy of formation of DAP-4 was determined as 278.6kJ/mol. At a heating rate of 20℃/min, the peak temperature of thermal decomposition reached 392.5℃, the activation energy of thermal decomposition(E_K)was 247.2kJ/mol, and the critical temperature of thermal explosion(T_b)reached 631.6K, which was much higher than that of HMX. The impact sensitivity of DAP-4 was similar to that of TNT, and the friction sensitivity was closed to CL-20. The detonation velocity of DAP-4 was as high as that of RDX. The chemical energy storage, work capacity, and metal acceleration ability of DAP-4 and its mixed explosives were significantly higher than those of RDX and HMX, which was closed to CL-20. The constant volume combustion experiment showed that the CMDB-1 propellant containing DAP-4 had the fastest burning rate, the highest combustion pressure, and the highest pressurization rate. The constant pressure combustion data showed that the combustion temperature of CMDB-1 propellant was the highest, which can reach 3501℃.

A new energetic metal-organic framework, [Ag₂(HOBTT)]_n, was prepared by solvothermal method using 4, 5-bis(1-hydroxy-tetrazol)-1,2,3-triazole(H₃OBTT)as ligand and Ag(Ⅰ)as metal center. The structure was characterized by single crystal X-ray diffraction(SXRD), powder X-ray diffraction(PXRD), infrared spectroscopy(IR)and elemental analysis(EA). The thermal stability was studied by differential scanning calorimeter(DSC)and thermogravimetric(TG)analyzer. The non-isothermal kinetic parameters of thermal decomposition were calculated by Kissinger's method. The mechanical sensitivities of [Ag₂(HOBTT)]_n were investigated by impact sensitivity meter and friction sensitivity meter. The GGA-PBE functional was used to calculate the detonation heat, and the detonation velocity and detonation pressure were obtained by Kamlet-Jacobs equation. The results show that [Ag₂(HOBTT)]_n is a three-dimensional solvent-free framework, belonging to the orthorhombic crystal system and Fddd space group with crystal density of 3.309g/cm³. The initial thermal decomposition temperature of [Ag₂(HOBTT)]_n is 586.6K, corresponding thermal decomposition kinetic parameters E_a=255.18kJ/mol and ln(A/s^-1)=43.30. Its impact sensitivity is greater than 40J, friction sensitivity is 108N, detonation velocity and detonation pressure are 9.73km/s and 56.38GPa, respectively, showing that [Ag₂(HOBTT)]_n is a kind of promising energetic material with good thermal stability,moderate mechanical sensitivity,and excellent detonation performance.