As a 3D printing method, laser powder bed fusion (LPBF) technology has been extensively proven to offer significant advantages in fabricating complex structured specimens, achieving ultra-fine microstructures, and enhancing performances. In the domain of manufacturing melt-grown oxide ceramics, it encounters substantial challenges in suppressing crack defects during the rapid solidification process. The strategic integration of high entropy alloys (HEA), leveraging the significant ductility and toughness into ceramic powders represents a major innovation in overcoming the obstacles. The ingenious doping of HEA particles preserves the eutectic microstructures of the Al2O3/GdAlO3(GAP)/ZrO2 ceramic composite. The high damage tolerance of the HEA alloy under high strain rates enables the absorption of crack energy and alleviation of internal stresses during LPBF, effectively reducing crack initiation and growth. Due to increased curvature forces and intense Marangoni convection at the top of the molt pool, particle collision intensifies, leading to the tendency of HEA particles to agglomerate at the upper part of the molt pool. However, this phenomenon can be effectively alleviated in the remelting process of subsequent layer deposition. Furthermore, a portion of the HEA particles partially dissolves and sinks into the molten pool, acting as heterogeneous nucleation particles, inducing the formation of equiaxed eutectic and leading primary phase nucleation. Some HEA particles diffuse into the lamellar ternary eutectic structures, further promoting the refinement of eutectic microstructures due to increased undercooling. The innovative doping of HEA particles has effectively facilitated the fabrication of turbine-structured, conical, and cylindrical ternary eutectic ceramic composite specimens with diameters of about 70 mm, demonstrating significant developmental potential in the field of ceramic composite manufacturing.

Laser powder bed fusion (LPBF) represents an advanced and versatile technology. Exploiting its distinctive advantages for direct and rapid fabrication of complex-structured melt-grown oxide eutectic ceramic composite represents a pioneering yet challenging endeavor. In this work, LPBF is creatively employed to fabricate turbine blade-shaped, in-situ ternary eutectic ceramic composite. Through the integration of experimental procedures, Finite element method (FEM) simulations, and numerical analyses, an innovative design and manufacturing of oxide eutectic ceramic composites have been successfully established. Comprehensive FEM simulations, with detailed interface characteristic analysis, have revealed macro-scale cracks induced by intense maximum principal stress, and micro-cracks stemming from significant interfacial energy disparities among the three constituent phases. The applications of rapid solidification and nucleation theories have facilitated profound insights into the formation mechanisms of multi-scale exotic microstructures, including top-layer coarse dendrites, rosette-like spherical internally grown eutectic colony within layers, and columnar eutectic colonies with ultrafine lamellar eutectic structures. Micro-mechanical property testing reveals enhanced performance in the interlayer ultra-fine lamellar eutectic structure, which is attributed to a refined eutectic spacing of approximately 61 nm, coupled with distinct and robust bonding interfaces. These groundbreaking achievements, focusing on the processing-microstructure-property relationship in the fabrication of gas turbine blade-shaped solidified eutectic ceramic composite using LPBF, provide invaluable theoretical insights and data. This knowledge is crucial for the LPBF production of high-temperature structural materials, highlighting its significant potential applications in fields of aerospace and mechanical engineering.

Eutectic high-entropy alloys (EHEAs) display superior mechanical properties, attributed to their lamellar structure characterized by alternating soft and hard phases. To address the critical demands for aerospace and high-end precision manufacturing equipment, a microalloying strategy has been employed to further achieve the balance of strength and ductility. Herein, we report that a unique AlCoCrFeNi2.1 EHEA, doped with a trace amount of boron (300 ppm), manufactured by laser powder-bed fusion (LPBF), exhibiting a remarkable balance between strength and ductility after heat treatment. It achieves a yield strength of 1177 MPa, an ultimate tensile strength of 1517 MPa, and an elongation of 17.6%. As compared with the undoped as-deposited samples, the boron-doped heat-treated alloys show a modest decrease in strength but a more than twofold increase in elongation. The doping of boron leads to a higher B2 phase content in the boron-doped as-deposited AlCoCrFeNi2.1 samples, facilitating the formation of additional FCC precipitates during heat treatment and thus preserving the strength of the samples. Furthermore, a greater volume fraction of the FCC phase and lower residual stress positively impact the ductility of the samples. These results establish a theoretical foundation for the advancement of high-performance EHEA by additive manufacturing.

Oxide eutectic ceramics have excellent high specific strength , high temperature resistance , corrosion resistance , oxidation and creep resistance , and so on , which are considered to be the promising materials to be used in ultra -high temperature oxidation , corrosion and other extreme environments. It shows great application prospects in the new generation of high thrust -to -weight ratio aero-engine for hightemperature hot -end structural components. Laser additive manufacturing technology has become one of the most promising cutting -edge technologies for the preparation of high-performance complex structural components in recent years. Crack defect is easy to occur in the process of laser rapid solidification of ceramics , which seriously affects the quality and performance of the oxide eutectic ceramics components. So , it has become a key factor restricting the engineering application. Two typical laser additive manufacturing technologies for ceramics including laser engineered net shaping and laser power bed fusion were briefly summarized. The crack morphology characteristics of different shaped components formed by the above two technologies were analyzed and compared. The formation mechanism of cracks in laser additive manufacturing of oxide ceramics was explored from the perspectives of microstructure characteristics ,stress state. Further ,a systematic summary was presented focusing on the improvement of microstructures and the reduction of thermal stress to inhibit crack formation through optimization of process parameters ,compositional design ,and outfield assistance. Finally ,it is pointed out that the future development trends and breakthrough directions of oxide eutectic ceramics by laser additive manufacturing in terms of and factors ,and research.

The strength and ductility cannot achieve a good tradeoff for some superalloy (e.g. GH3536) prepared by selective laser melting (SLM), which seriously restricts their industrial applications. This work examined the effect of post-heat treatment (HT) on the microstructure and mechanical properties of GH3536 produced by SLM. In particular, the influence of carbide precipitate morphology and distribution on strength and ductility of the alloy after heat treatment was discussed. After aging at 650 °C (denoted as HT1), the Cr23C6 carbides were distributed in chains. The ductility increased by approximately 31

Laser power bed fusion (LPBF) as a widely used laser additive manufacturing, which has demonstrated a promising capability in the simultaneous formation of high-performance composites with unique microstructure. In order to further meet the urgent needs of aerospace sophisticated equipment, this work investigated the laser additive manufacturing of CrFeNb particles reinforced Ni-based superalloy composites with grain refinement and superior performance. A few CrFeNb particles were added to IN718 superalloy powder. The CrFeNb particles as a center of heterogeneous nucleation effectively facilitated to produce fine equiaxed grains and did not introduce significant residual stress in the as-deposited IN718 with CrFeNb composites. The stress concentration of the heat-treated IN718 with 4 wt.% CrFeNb composites was significantly reduced. The grain orientation was not along the <001> and tended towards random. The particle size of as-deposited IN718 with 4 wt.% CrFeNb composites was refined and the average size was 13.46 μm. The unmelted CrFeNb particles were dissolved and diffused into the γ matrix during heat treatment. A hard brittle phase was rich in Nb and Mo elements along the grain boundary. Under the combined effect of three strengthening mechanisms, the mechanical properties of the IN718 with 4 wt.% CrFeNb composites at room temperature were improved. The yield strength, tensile strength and microhardness of the heat-treated IN718 with 4 wt.% CrFeNb composites reached to 1194 MPa, 1426 MPa and 521 HV, respectively. This study provides a new method and foundation for the preparation and application of IN718 composites with excellent performance.

The rapid advancement of high-tech technologies such as aerospace， electronic information， and biomedicine has required more demands on the properties of advanced ceramic materials. Single-characteristic structural or functional materials cannot meet the current requirements， so the high-performance composite ceramics with integrated structure and function have become global research objectives. Directionally solidified oxide eutectic composite ceramics are a class of structural and functional integrated composite materials developed in recent years for long-term service in ultra-high temperature oxidizing environments. They have characteristics such as high melting point， low density， excellent high-temperature strength， and high-temperature creep performance， while also possessing functional properties such as optics， electromagnetism， and biology. The latest development of directionally solidified structure-function integrated eutectic ceramics was reviewed， specifically focusing on Al2O3-based eutectic ceramic systems. The various preparation methods， technical principles， and growth characteristics associated with directionally solidified eutectic ceramics were summarized. Furthermore， the solidification microstructure and structural characteristics observed in a series of Al2O3-based eutectic ceramics were elaborated. The mechanical， optical， magnetic， and biological properties of composite ceramics and their influencing factors were analyzed， and their characteristics， advantages， and application scope were introduced. Finally， the review summarizes the challenges and key bottlenecks faced by directionally solidified eutectic composite ceramics in engineering applications and proposes the main directions for the development of eutectic composite ceramic materials in terms of forming technology innovation， comprehensive performance improvement， and the development of new systems.

Incomplete combustion of Al in solid propellants can be effectively resolved by coating of an oxidizer at the microscale. In this paper, Al@CL-20 composites with polydopamine as the interfacial layer were prepared using this strategy. The structure, heat of reaction, thermal decomposition properties, and combustion performances of these composites under the effects of graphene oxide (GO) and graphene-based carbohydrazide complexes (GO-CHZ-M, M = Co2+, Ni2+) have been comprehensively investigated. The experimental results show that the heat of reaction of Al@CL-20 is 6482 J g(-1), which is 561 J g(-1) higher than that of the corresponding mechanical mixture. The presence of GO-CHZ-Co can further increase the heat of reaction of Al@CL-20 to 6729 J g(-1) with a decreased activation energy by about 54.8%. Under the synergistic effect of interfacial control and GO-CHZ-M, the ignition delay time of Al@CL-20-Co decreases from 5.1 to 4.2 ms. Besides, the D-50 of the combustion condensed products (CCPs) decreased from 5.62 to 4.33 mu m, indicating the combustion efficiency of Al is greatly improved.

2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) is one of the high-energy oxidants, but has limited application due to its high sensitivity. In this work, polyvinylidene fluoride (PVDF) was used as a co-oxidizer, which is expected to increase the safety of CL-20. One kind of novel graphene-based carbohydrazide complex (GCCo and GCNi) was employed to modify the properties of dual-oxidant CL-20@PVDF composites by the spray drying method and compared with traditional nanocarbon materials (CNTs and GO). The properties of these composites were investigated using the TGA/DSC technique and impact test. The results show that GCCo and GCNi could increase the activation energy (Ea) of CL-20@PVDF composites, and change the physical model of CL-20@PVDF, which followed the random chain scission model and then the first-order reaction model. In addition, these nanocarbon materials could reduce the impact sensitivity of CL-20@PVDF by their unique structure. Besides that, a dual-oxidant CL-20@PVDF system was used to improve the combustion property of Boron. GCCo and GCNi with the synergetic effect could increase the flame temperature and control the burn rate of CL-20@PVDF@B compared with CNTs and GO. The energetic nanocarbon catalyst-modified oxidant provides a facile method for stabilizing high-energy but sensitive materials to broaden their application.

In this study, to effectively reduce the mechanical sensitivity of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaiso-wurtzitane (CL -20) while maintaining its high energy density, an interfacial controlled self-assembly technique was employed to prepare co-particles containing minimal amounts of nano-sized insensitive compounds. Herein, 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), a commonly used insensitive energetic compound, was employed. Through the spray drying technique, CL -20 and nano-sized TATB@polydopamine (PDA) were effectively assembled into spherical co-particles with varying TATB contents (1, 5, and 10 %). The scanning electron microscopy images revealed the co-particles to have a football-shaped morphology. Notably, a part of the CL -20 had crystallised as a compact shell with a trace amount of nTATB@PDA on the surface, while most of CL -20 was embedded in the co-particles. The strong intermolecular interactions between the compact CL -20 shells and nTATB@PDA were confirmed through Raman and infrared spectroscopy analyses. For instance, the co-particles with 10 % nTATB@PDA exhibited 2 degrees C higher peak decomposition temperature compared to raw epsilon-CL-20, indicating improved thermal stability. Furthermore, thermal gravimetric analysis results revealed that the co-particles underwent one-step thermal decomposition, while the mixture decomposed in two steps (at the same ratio) due to the differing thermal stabilities of CL -20 and TATB. In terms of safety, the co-particles demonstrated an impact initiation energy of 16 J, which is five times higher than raw CL -20. Additionally, the friction sensitivity of co-TATB P10% /CL-20 decreased from 100 to 80 %. Despite great improvements in sensitivity, the density of the co-particles remained almost the same as that of epsilon-CL-20. Overall, these findings underscore the effectiveness of co-particle technology in reducing the mechanical sensitivity while enhancing the thermostability of CL -20, all whilst maintaining the energy density.

Recognizing the strong potential of cold cathodes for important commercial applications in fields such as electronics, there is a growing interest in the exploration of novel 1D nanomaterials. Among various cold cathode materials, TaSi2 is of great interest for its outstanding field emission performance. In this work, the Si-TaSi2 eutectic composite with nano-sized highly oriented TaSi2 fibers and semi-coherent phase interfaces is prepared by the laser floating zone melting technique with a very high-temperature gradient of 6000 K cm(-1) at a solidification rate of 200 mu m s(-1). On the basis of directionally solidified Si-TaSi2 eutectic composite, well-aligned TaSi2 nanorod and nanotip arrays are fabricated by inductively coupling plasma (ICP) etching process and HNO3/HF wet etching process, respectively. The field emission measurements show that the field enhancement factor, turn-on electric field, and effective work function are strongly affected by tip morphologies. The TaSi2 array with regular nanotip structure possesses the best field emission characteristic among all TaSi2 nanostructures, with a relatively low turn-on field of 4.8 V mu m(-1) and a high current density of 733 mu A cm(-2). These findings preliminarily establish a clear relationship between the performance and structure of the array, providing technical guidance for the application of this material in electronic devices.

Aluminum hydride (AlH3) is considered as one of the most promising high-energy hydrogen-storage fuels. Various studies have been conducted to improve its thermostability and compatibility with polar plasticizers. As frequently reported, polyvinylidene difluoride (PVDF) has inherent advantages as a coating agent of AlH3 to improve its stability and compatibility. However, its optimal content and the interaction mechanisms with AlH3 are still not clear. In this study, AlH3 crystals coated with different contents of PVDF have been prepared and their thermochemical properties have been analyzed by using VST and DSC/TG techniques. In addition, the effect of PVDF on decomposition reaction pathways of AlH3 and AlH3@Al2O3 have been investigated using RMD simulations. It has been found that if the content of PVDF is less than 8%, it may enhance the stability of AlH3. However, once the content is over 20%, the decomposition of AlH3 would be promoted. In addition, even if PVDF can inhibit the initial dehydrogenation of AlH3 during the induction period, once the fast exothermic reactions initiate, the corresponding energy barriers would be lowered with faster H-2 release.

Vat photopolymerization (VPP) is a high potential and efficient method for fabricating advanced ceramics. However, the selection of printing strategy importantly determines the geometrical accuracy and mechanical strength of ceramic parts prepared by VPP. In this study, the effects of the curing depth (C-d) to layer thickness (L-t) ratio and L-t on forming accuracy, microstructures, mechanical properties, surface roughness of biphasic calcium phosphate (BCP) bioceramic green bodies and sintered bodies were investigated. When the C-d/L-t ratio was smaller than 4.0, and the L-t was not over 50 mu m, the green bodies presented high forming accuracy (the dimension errors < 3.50 %). Inappropriate C-d/L-t and L-t caused lots of defects including different types of cracks and delamination on green bodies and sintered bodies, and impaired their mechanical strength. The optimal C-d/L-t ratio and L-t were obtained to be 4.0 and 50 mu m, in which parameters there were few cracks and delamination on the sintered BCP bioceramics. The flexural strength and the fracture toughness of sintered BCP increased when the C-d/L-t ratio increased from 3.0 to 4.0. However, the flexural strength and the fracture toughness decreased when the C-d/L-t ratio further increased to 5.0. The flexural strength of sintered BCP increased at first and then decreased when the L-t increased from 25 mu m to 50 mu m, and the fracture toughness and hardness of BCP decreased continually. The flexural strength of sintered BCP showed a maximum value of 113.21 MPa, and the maximum fracture toughness was 0.71 MPa center dot m(1/2). The elastic modulus and hardness of sintered BCP also reached 24.16 GPa and 3.04 GPa, respectively. The printing surface roughness of BCP bioceramics decreased when the C-d/L-t ratio or L-t increased. The lateral surface roughness decreased with the increase of C-d/L-t ratio, and increased with the increase of L-t. This new result provides a clear printing strategy for fabricating ceramics with high geometrical accuracy and mechanical properties by VPP technique.

In order to study the effect of cellulose shell on the thermal behavior including pyrolysis gaseous products, ignition and combustion characteristics of typical pyrotechnics, three composites of pyrotechnics/cellulose were prepared in this paper. Various characterization techniques were used to investigate the prepared composites and their combustion condensed products (CCPs), including scanning electron microscopy (SEM), simultaneous thermal analysis (DSC-TG-FTIR), X-ray diffraction (XRD), bomb calorimetry, and home-made combustion diagnostic system. The results showed that the overall heat release of the black powder and Mg/PTFE decreased from 3108 J center dot g(-1) and 1157.4 J center dot g(-1) to 1045.4 J center dot g(-1) and 810.4 J center dot g(-1) in the presence of 33.3% cellulose, respectively. Moreover, the FTIR spectra showed that the cellulose did not change the reaction pathways of black powder and Mg/PTFE, which mainly include H2O, CO2, NO2 for the black powder, and HF, H2O, C(O)2, CF2 for Mg/PTFE. However, the condensed products of cellulose would interact with B/KNO3 at a higher temperature, so that the heat release was largely increased by 339%. The cellulose has obviously impact on the energy release rate of Mg/PTFE in comparison to the other two composites. Moreover, the negative impact on ignition of Mg/ PTFE composite is significant, when the content of cellulose reaches over 33.3%, resulting in difficult selfsustainable combustion at ambient pressure. The cellulose can largely reduce the maximum flame temperature of the black powder and Mg/PTFE, whereas it has little effect on B/KNO3. The CCPs of the involved igniting pyrotechnics and their cellulose-based composites have different phases due to their strong thermal interactions with cellulose.

Highly dense Al2O3/GdAlO3/ZrO2 eutectic ceramics are one-step additively manufactured by laser directed energy deposition technique under different scanning speed to investigate the inherent response relationship between processing parameter, microstructure, and mechanical property. During the layer-wise deposition process, planar-cellular transition occurs near the bottom of the molten pool, leading to the transformation of irregular eutectic structure into eutectic colony structure lengthened along the building direction, accompanied by the refinement of microstructure dimension. With the increase of scanning speed, the eutectic spacing decreases, and the initially irregular “Chinese script” eutectic ultimately transforms into hexagonally arranged rod-like eutectic structure induced by lamellar instability. The rod spacing is 1.136 times larger than the lamellar spacing. The mechanical property of the laser 3D-printed Al2O3/GdAlO3/ZrO2 eutectic ceramic is manifested as isotropic. The hardness increases with the refinement of the microstructure, while the fracture toughness decreases as the eutectic morphology transforms into rod-like structure. The averaged hardness and fracture toughness are 16.27 GPa and 3.39 MPa‧m1/2, respectively.

Laser directed energy deposition (LDED) is a promising technology for preparing complex-shaped melt-grown Al2O3-based ceramics which are important candidates for new high-temperature structural materials. The characteristics of ceramic powder particle significantly affect the stability of LDED process and the forming quality of ceramic samples. In this study, rod-like and thin-walled Al2O3 ceramics were one-step fabricated by LDED by using the plasma spheroidized alumina powder (PSAP) and irregular alumina powder (IAP), respectively. The differences in forming quality and mechanical properties of the specimens prepared by the above two powders were analyzed and discussed. Both powders achieved high-quality forming of rod-like samples with high relative densities of more than 99% and 98%, respectively. The flowability of IAP met the fundamental forming requirements of LDED technology. The microhardness and fracture toughness of the Al2O3 ceramics obtained by using IAP were 17.77 +/- 0.97 GPa and 4.58 +/- 0.50 MPa & sdot;m1/2, respectively. Due to the angular shape and narrow particle size distribution of IAP, there were lack-of-fusion (LOF) pores at the grain boundaries. Intergranular oxide impurities and LOF pores reduced the flexural strength. In contrast, the flexural strength of Al2O3 ceramics prepared by PSAP reached 276.6 +/- 22.9 MPa due to the columnar crystals with highly consistent growth orientation. Combining the reduction of line energy density and the supplement of additional laser energy input, crack-free thin-walled Al2O3 ceramics with a width of 30 mm were successfully manufactured using PSAP. Its relative density was close to 99%, and the forming error of width direction was only 5.7%. The study demonstrates the profound influence of powder particle shape on the forming quality of LDED, which provides an essential reference for laser additive manufacturing of high-quality Al2O3-based ceramics.

Cylindrical Al2O3/GdAlO3 binary in situ oxide eutectic ceramic composite, with a glossy surface and high relative density, has been fabricated using the laser directed energy deposition method (LDED) with optimized process parameters. In a novel and innovative approach, infrared thermal imaging and the finite element method (FEM) have been combined for the first time to capture the temperature field distribution across different regions of the molten pool during the LDED processing of the binary oxide eutectic ceramic composite, thereby synergistically obtaining the solidification characteristics. With an increase in the scanning rate, the temperature gradient within the molten pool decreases from 3.38 x 105 K/m to 1.62 x 105 K/m, while it shows minimal variation with fluctuations of the laser power. Under the conditions of high temperature gradients and rapid non-equilibrium solidification characteristic of LDED, the Al2O3/GdAlO3 (GAP) binary eutectic ceramic composites, which exhibit typical high melting entropy and faceted/non-faceted growth modes, exhibit complex and variable microstructure morphology. A combination of regular/irregular models, including JH (Jackson-Hunt), MK (Magnin-Kurz), GK (Guzik-Kopycinski) and TMK (Trivedi-Magnin-Kurz), is employed to investigate and predict the growth and transformation of microstructures. The JH and TMK models fairly predict the rod-like regular eutectic microstructure inside the colony and lamellar regular eutectic within adjacent layers, respectively. The "Chinese-script" irregular microstructure at the interface between the colony and the layers is consistent with the MK and GK models. The as-deposited eutectic ceramic composite presents ultra-fine microstructures, clear and strongly bonded phase interfaces with low strain energy, contributing to its microstructure stability after high temperature heat treatment at 1773 K for 200 h, and achieving a minimum microstructure coarsening rate of 0.0005 mu m/h.

Aluminum hydride (AlH3) has attracted much attention due to its potential to replace aluminum (Al) as a novel energetic material in solid propellants. In this research, ammonium perchlorate (AP) and perfluoropolyether (PFPE) as functionalized coatings and a combination of acoustic resonance and spray drying technology have been employed to prepare AlH3@Al@AP (AHAPs) and AlH3@Al@AP@PFPE (AHAPs-F) energetic composite particles. The formulations of composite propellants and modified AlH3 particles were designed and fabricated. Their thermal reactivity, reaction heat, density, vacuum stability, combustion performance, and condensed combustion products (CCPs) have been systematically investigated. The results show that the solid propellants containing AHAPs (SP13) and AHAPs-F (SP14) composites can significantly enhance the reactivity and energy output compared to conventional solid propellants with the mechanical mixture Al/AlH3 (SP12). In particular, the total heat releases of SP13 and SP14 are almost 1.2 and 1.7 times higher than those of conventional ones (SP12, 1442 J g-1), respectively. Among the AlH3-based propellants, SP14 propellants exhibit the highest reaction heat of 5887 J g-1, the most intensive flame radiation of 31.4 × 103, and the highest combustion wave temperature of 2495 °C. Moreover, the particle size distribution of CCPs from SP14 propellants is much narrower and smaller than that of SP12, resulting in higher combustion efficiency.

Aluminum hydride (AlH3), as a promising fuel, has been utilized to improve the energy performance of pro-pellants. Moreover, the inherent compatibility and mutual interaction between AlH3 and the commonly used oxidizers of solid propellants are the basics of propellant formulation design. Herein, the homogenous composites of AlH3/oxidizer have been prepared by the in-situ recrystallization method, and then their thermal stability, compatibility, and ignition performance have been investigated. The initial decomposition temperatures (T-i) of AlH3 in composites are increased by at least 16 degrees C, whereas the thermal decomposition peak temperatures (T-p) of involved oxidizers are lower than that of their pure state. The compatibility tests showed that AlH3 is compatible with the mentioned oxidizers. In particular, the induction time of the dehydrogenation of AlH3 in presence of these oxidizers is improved by almost 1.2 times that of raw AlH3, which means that the oxidizers have an un-expected strong stabilization effect on AlH3 due to strong hydrogen bonding. Moreover, the optimized contents of AlH3 in AlH3/HMX, AlH3/CL-20, and AlH3/AP composites have been determined to be 45 %, 40 %, and 33 %, which have the maximum flame temperatures of 1275.3, 1440.4, and 1616.8 degrees C, respectively. Besides, AlH3/CL-20 has the strongest flame radiation intensity (18.5 K) and shortest ignition delay time (32.2 ms) among the involved

The combustion efficiency of Al plays a critical role in the combustion of high-energy aluminum-based solid propellants. For traditional formulations, the Al powders are dispersed in the binder matrix, leading to limited contact with the oxidizers and hence usually insufficient combustion and higher values of the pressure exponent. In this paper, various core-shell structural Al/oxidizer composites such as Al@HMX, Al@AP, and AP@Al have been prepared by a spray-drying technique based on which solid propellants with precise interfacial control between Al particles and oxidizers were realized. Compared to the control sample, the modified propellants have a greater heat of explosion of 5890 J g-1 (15% higher) and a reduced ignition delay time of 58 ms (65% decrease). Without changing the content of components, the burn rates of propellants can be easily modulated by tuning the interfacial contact of Al and oxidizers, where it varies in a wide range of 4.56-5.79 mm s-1 at the same pressure of 1 MPa. After introducing Al/oxidizer composites, the lowest pressure exponent of 0.19 within 1-15 MPa could be achieved by using Al@HMX and AP@Al composites. The agglomeration of Al was also inhibited by using Al/oxidizer composites, and the mechanism can be interpreted by using a classical "pocket" model. Moreover, the improved combustion efficiency of the solid propellants was verified by a noticeable reduction in the unreacted Al content.