Abstract:In order to develop a scale-up and continuous preparation method， the microchannel crystallization technology based on solvent/non-solvent method has been used to prepare hexanitrohexaazaisowurtzitane/octogen （CL-20/HMX） co-crystal. The field emission scanning electron microanalyzer （FE-SEM）， X-ray powder diffraction （XRD）， Raman spectroscopy， Fourier infrared spectroscopy （FT-IR）， thermal analysis and sensitivity test were applied to characterize and analyze the morphology， structure， thermal performance and sensitivity of samples. Results show that this method has successfully prepared CL-20/HMX co-crystal. Its apparent morphology is the flower clusters with a diameter of 20-30 μm， assembled by platelet crystals with thickness of 200-600 nm， accompanying individual flaky crystals （thickness of 200-600 nm）. The CL-20/HMX co-crystal prepared by microchannal crystallization has only one sharp exothermic decomposition peak during the exothermic process. Its exothermic peak temperature is at 243.4 ℃， which is lower than that of the raw materials CL-20 （250.2 ℃） and HMX （284.7 ℃）. Its temperature range of thermal decomposition is only from 242.7 to 246.0 ℃， much narrower than those of raw CL-20 （230.0-254.6 ℃） and HMX （281.0-290.7 ℃）， which means a higher energy release efficiency. Its apparent active energy is 470.75 kJ·mol^-1，falling between CL-20 （175.04 kJ·mol^-1） and HMX （481.45 kJ·mol^-1）， which is 297.29 kJ·mol^-1 hagher than that of raw CL-20，indicating a good thermal stability. Its impact sensitivity is 18 J， which is 8 J and 3.6 J higher than those of raw CL-20 （10 J） and HMX （14.4 J） respectively， and the friction sensitivity is 20% lower than that of raw CL-20. The sensitivity results show the safety of the CL-20/HMX co-crystal has been improved compared with the raw materials.

Abstract:In order to study the influence of modification technology on the ignition and explosion characteristics of the composite hydrogen storage materials， the combustion heat of Al， MgH₂， Hydrogen storage material CM and hydrogen storage material CM-H coated with hydroxyl terminated polybutadiene （HTPB） was measured by an oxygen bomb calorimeter， and the mass change of the four samples within 48 h was test as well. Results show that CM-H has the highest combustion heat for 30.5633 MJ·kg^-1. Meanwhile its mass gained within 48 h in air is the least for 0.46%. Result show that the modification can effectively prevent the performance degradation of the materials so that they can maintain a high combustion heat. The minimum ignition energy， flame propagation characteristics and explosion pressure of the four samples were studied by an 1.2 L Hartmann tube， a high-speed camera and a 20 L ball explosion test device respectively. Results show that the minimum ignition energy of CM is 50-60 mJ， which was only a half of the critical ignition energy of aluminum powder （100-150 mJ）. It indicated that the addition of MgH₂ into metal materials can effectively reduce the ignition energy. The minimum ignition energy of CM-H dramatically increased to 700-750 mJ after coating. The test results of flame propagation speed， explosion pressure and explosion index presented the performance order of MgH₂ > CM > CM-H > Al. Results indicat that the modified composite hydrogen storage material has lower electric spark sensitivity， higher safety and better explosion performance.

Abstract:With the deepening and development of the concept of long-range operations， long-range strike of missile has become an indispensable part of modern warfare. Therefore， the damage assessment of target hit by missile warhead has been the focus of damage research in recent years. Research of damage assessment in the process of missile warhead striking the target are summarized from four aspects： damage assessment model of target， main subjects in damage process， damage of classified targets， and methods of damage assessment， respectively. Problems such as non-standard judgment of damage degree， unclear relationship of damage mapping and inaccurate solution of damage probability in current stage are pointed out. According to the insufficiency of current study， some suggestions are proposed for the research in the future， which can provide reference for the investigations in the related fields.

Abstract:Six preparation methods of physical mixing， ball milling， vapor deposition， electrostatic spray/spinning， solvent/non-solvent and 3D printing for aluminum-fluoro reactive materials are summarized. Recent research progress of Al-fluoropolymer reactive materials are reviewed from the aspect of product performance and method advantages and disadvantages. The reaction process of aluminum-fluoropolymer reactive materials at slow heating rate and fast heating rate are introduced. The promising research directions in the future are pointed out， including design a new method that combines the advantages of various preparation methods and more attention should be paid to strengthen the research on the reaction mechanism of aluminum-fluoropolymer reactive materials when heated.

Abstract:In order to get the phase diagrams of 3，4-dinitropyrazole （DNP）/3，4-bis（3-nitrofurazan-4-yl） furoxan （DNTF） binary mixture system and understand the eutectic melting process， DSC was used to investigate the liquefaction and melting process of DNP/DNTF mixed system with different proportions. The T-x phase diagram and H-x phase diagram were established， and the effects of different heating rates and additives on melting process of eutectic were studied. Finally， the kinetic parameters E_a and A of eutectic melting process were calculated by Kissinger equation and Šatava-Šestak equation. Results show that the mass percentage of DNP/ DNTF eutectic is 70.38/29.62 and the eutectic temperature is 76.38 ℃ based on T-x phase diagram， which is good consistent with that from H-x phase diagram as 70.57/29.43. With the increase of heating rate， the initial temperature and peak temperature of melting process are delayed correspondingly. After the addition of Octogen （HMX） and nitroguanidine （NQ）， the melting point of the low eutectic is significantly delayed， while ammonium perchlorate （AP） has little effect on the melting point. The melting kinetic parameters E_a and A of DNP/DNTF eutectic are 19.13 kJ·mol^-1 and 10^9.74 s^-1 respectively， and the integral form of the most probable mechanism function is： G（α）=（1-α）^-1-1.

Abstract:A pair of pressed combined CL-20-based and JO-8（HMX-based）explosives are selected to investigate the improvements in the explosion driving performance by using more powerful explosive. This paper presents the test results of detonation velocity， detonation pressure and Gurney coefficient from devices loaded by CL-20-based explosive and JO-8， respectively. Enhanced warhead performance has been demonstrated in static experiments of prefabricated fragment warhead and shaped charge. The results show that the fragment velocity （kinetic energy） driven by CL-20-based explosive is 5.1%-7.3% （10.5%-15.1%） higher than that driven by JO-8. The penetration of shaped charge loaded by CL-20-based explosive is 3.2%-12.6% larger than that loaded by JO-8.

Abstract:With extrusion deposition technology as the core， based on the features of high viscosity and no-resistant to high temperature for propellant， the extrusion deposition rapid prototyping system for propellant was designed and a complete prototype was built. Using a certain ZY propellant as raw material， different materials with concentrations of 27.3%， 33.3%， 38.5%， 42.9%， 46.7% and 50% were prepared. Through 3D printing extrusion experiments， it is found that there is a polynomial function relationship between the inner diameter of the needle and the material concentration. The filling speed range is 2-4 mm·s^-1， the filling rate range is 70%-90%， and the temperature range of the bottom plate is 25-45 ℃. On this basis， the propellant 3D printer was used to print the propellant， and the compression test was carried out. The results showed that the compression strength of the propellant could reach up to 230 MPa.

Abstract:As a typical representative of the third generation energetic materials， 2，4，6，8，10，12-hexanitro-2，4，6，8，10，12-hexaazaisowurtzitane （CL-20） is currently the most powerful energetic compound that has already been commercially available. The important research directions are， at present， the optimum synthesis of CL-20 and the preparation of CL-20-based high energy and low sensitivity energetic compounds in the development of energetic materials. The development status of the intermediates in the preparation of CL-20 was analyzed and summarized. The solutions and prospects of the intermediates were also proposed. In addition， the research progress， structural characteristics and main properties of CL-20 crystal products were also discussed. Through sorting out the synthesis and crystals of CL-20， it is concluded that low-cost， high yield， high purity and environmental friendliness are the future development direction of the synthesis process of CL-20.

Abstract:To investigate the coupling effect and propagation law of shock wave for underwater array explosion with multiple charges. The shock wave parameters of group charge， two charges and four charges were measured by underwater explosion test. The influence of charge quantity and array distance on peak pressure， impulse and loading time of shock waves were analyzed and revealed the relationship beween array explosion shock wave parameters and distances. The results showed that the shock wave （symmetrical center line） can be superimposed in the focusing direction for two-charge explosion. The shock wave pressure intensity increased by 22.8%-55.4% in the scale distance of 2-6 m·kg^-1/3， and the gain increased gradually with the increase of propagation distance. For four-charge array explosion， the peak pressure of the shock wave in the focusing direction was close to that of group charge. For the same explosion points and layout of the array explosion， the impulse and shock wave loading time can be improved by increasing the array distance. The loading time of shock wave pressure increased with the increase of charge quantity and array distance. For two-charge and four-charge explosion， the peak pressure and impulse of multiple shock waves were still consistent with explosion similarity law， but the loading time of shock wave pressure was not.

Abstract:The attachment energy （AE） model and molecular dynamics （MD） methods were used to predict the crystal morphology of 1，1-diamino-2，2-dinitroethylene （FOX-7） under vacuum condition and in eight solvent systems including dimethylsulfoxide （DMSO）， acetone， methanol， N-methylpyrrolidone （NMP）， N，N-Dimethylacetamide （DMAC）， ethylacetate （EA）， water （H₂O）， and DMSO/H₂O （V/V=2/1）. By calculating the interaction energies between the solvent and crystal plane， and the attachment energies under the influence of the solvent， the simulated crystal habit and its aspect ratio were obtained. The results show that FOX-7 crystal has six important growth planes under vacuum： （1 0 ）， （1 0 1）， （0 1 1）， （0 0 2）， （1 1 0）， （1 1 ）. Among them， the area of （0 1 1） plane accounts for the largest proportion， which is the most important crystal plane affecting the crystal morphology of FOX-7. The influence degree of solvent on the aspect ratio of crystal is in the following order： DMSO2O2O. By recrystallization experiments， FOX-7 crystals have a bulk-like shape in DMSO， methanol， and DMSO/H₂O； a rod-like shape in acetone and NMP； a needle-like shape in DMAC and H₂O； a flake-like shape in EA. The theoretical prediction results are in good agreement with the experimental results， which proves that the simulation of the crystal habit of FOX-7 based on the AE model can provide better guidance for the crystallization experiment. Results in thermal properties show that the crystal surface morphology and internal defects affect the phase transition temperature and thermal decomposition temperature of FOX-7. The fewer the crystal defects， the higher the α→β transformation temperature. The larger the crystal aspect ratio， the smaller the particle size， and the lower the first decomposition temperature.