Pub Date : 2025-06-01DOI: 10.1016/j.enmf.2024.02.004
Yao-yao Linghu , Chao-yang Zhang
Packing density is a basic property of substances and acts as one of important decisive factors of service performances. This work focuses upon the determining factors of packing density at the premise of CHON-containing isomers with the same chemical composition. It is found that, for a group of CHON-containing isomers, the molecular densities vary much less than the packing coefficients and packing densities, regardless a significant difference of molecular structure therein. Thus, packing coefficient governs packing density, and strategy based on data analysis for elevating it is proposed, such as the introduction of strong and dense hydrogen bonds and the formation of internal salt. Additionally, C=O is beneficial for increasing packing density while reducing energy release, and thus can hardly be considered in energetics. Hopefully, this work will deepen the understanding of packing density and offer a new avenue for designing high energy compounds.
{"title":"Packing coefficient determining the packing density difference of CHON-containing isomers","authors":"Yao-yao Linghu , Chao-yang Zhang","doi":"10.1016/j.enmf.2024.02.004","DOIUrl":"10.1016/j.enmf.2024.02.004","url":null,"abstract":"<div><div>Packing density is a basic property of substances and acts as one of important decisive factors of service performances. This work focuses upon the determining factors of packing density at the premise of CHON-containing isomers with the same chemical composition. It is found that, for a group of CHON-containing isomers, the molecular densities vary much less than the packing coefficients and packing densities, regardless a significant difference of molecular structure therein. Thus, packing coefficient governs packing density, and strategy based on data analysis for elevating it is proposed, such as the introduction of strong and dense hydrogen bonds and the formation of internal salt. Additionally, C=O is beneficial for increasing packing density while reducing energy release, and thus can hardly be considered in energetics. Hopefully, this work will deepen the understanding of packing density and offer a new avenue for designing high energy compounds.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 2","pages":"Pages 166-176"},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139815594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01DOI: 10.1016/j.enmf.2025.04.001
Rui-min Tang , Chen Wang , Mao-guo Zhu , Liang-liang Sun , Jian-xing Yang , Su-hang Chen , Feng-qi Zhao , Kang-zhen Xu
The pyrolysis behavior and mechanism of energetic materials are crucial for assessing their safety and application. In this study, the pyrolysis behavior, gas-phase decomposition products, condensate phase products and pyrolysis mechanism of high nitrogen compound 4,4′,6,6′-tetri(azide)-hydrazine-1,3,5-triazine (TAHT) were fully studied through differential scanning calorimetry (DSC), thermogravimetric analysis (TG), thermogravimetric-infrared-mass spectrometry (TG-IR-MS) and in-situ infrared spectroscopy. The results indicate that the thermal behavior of TAHT exhibits a big exothermic decomposition process and an endothermic decomposition process accompanied by the mass loss of 42.5 % and 52.1 %, respectively. At the heating rate of 10 °C·min−1, the peak temperature (Tp) and decomposition enthalpy of exothermic decomposition process are 230.4 °C and −2021.0 J g−1, respectively. The peak temperature (Tp) of endothermic decomposition process is 703.5 °C. In the exothermic decomposition stage, the main gas-phase decomposition products of TAHT are N2, and contain small amounts of NH3 and HCN, the hydrazine bond and azide groups in the condensed-phase almost completely disappear during the pyrolysis process, and the residues form a network structure of triazine ring. Based on the analysis of gas-phase and condensed-phase products, a possible pyrolysis mechanism for TAHT is proposed. This work provides valuable theoretical insights for the application of TAHT as a new green energetic material.
含能材料的热解行为和热解机理是评价含能材料安全性和应用前景的关键。本研究通过差示扫描量热法（DSC）、热重分析（TG）、热重-红外-质谱法（TG- ir - ms）和原位红外光谱技术，对高氮化合物4,4′，6,6′-四叠氮-肼-1,3,5-三嗪（TAHT）的热解行为、气相分解产物、凝析相产物和热解机理进行了全面研究。结果表明：TAHT的热行为表现为大的放热分解过程和吸热分解过程，质量损失分别为42.5%和52.1%。在升温速率为10℃·min−1时，放热分解过程的峰值温度（Tp）为230.4℃，分解焓为- 2021.0 J g−1。吸热分解过程的峰值温度Tp为703.5℃。在放热分解阶段，TAHT的主要气相分解产物为N2，并含有少量的NH3和HCN，在热解过程中缩合相的联氨键和叠氮基团几乎完全消失，残基形成三嗪环网状结构。通过对TAHT气相和冷凝产物的分析，提出了TAHT可能的热解机理。这项工作为TAHT作为一种新型绿色能材料的应用提供了有价值的理论见解。
{"title":"Pyrolysis behavior and mechanism of high nitrogen compound 4,4′,6,6′-tetra(azido)-hydrazine-1,3,5-triazine","authors":"Rui-min Tang , Chen Wang , Mao-guo Zhu , Liang-liang Sun , Jian-xing Yang , Su-hang Chen , Feng-qi Zhao , Kang-zhen Xu","doi":"10.1016/j.enmf.2025.04.001","DOIUrl":"10.1016/j.enmf.2025.04.001","url":null,"abstract":"<div><div>The pyrolysis behavior and mechanism of energetic materials are crucial for assessing their safety and application. In this study, the pyrolysis behavior, gas-phase decomposition products, condensate phase products and pyrolysis mechanism of high nitrogen compound 4,4′,6,6′-tetri(azide)-hydrazine-1,3,5-triazine (TAHT) were fully studied through differential scanning calorimetry (DSC), thermogravimetric analysis (TG), thermogravimetric-infrared-mass spectrometry (TG-IR-MS) and in-situ infrared spectroscopy. The results indicate that the thermal behavior of TAHT exhibits a big exothermic decomposition process and an endothermic decomposition process accompanied by the mass loss of 42.5 % and 52.1 %, respectively. At the heating rate of 10 °C·min<sup>−1</sup>, the peak temperature (<em>T</em><sub>p</sub>) and decomposition enthalpy of exothermic decomposition process are 230.4 °C and −2021.0 J g<sup>−1</sup>, respectively. The peak temperature (<em>T</em><sub>p</sub>) of endothermic decomposition process is 703.5 °C. In the exothermic decomposition stage, the main gas-phase decomposition products of TAHT are N<sub>2,</sub> and contain small amounts of NH<sub>3</sub> and HCN, the hydrazine bond and azide groups in the condensed-phase almost completely disappear during the pyrolysis process, and the residues form a network structure of triazine ring. Based on the analysis of gas-phase and condensed-phase products, a possible pyrolysis mechanism for TAHT is proposed. This work provides valuable theoretical insights for the application of TAHT as a new green energetic material.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 2","pages":"Pages 195-201"},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01DOI: 10.1016/j.enmf.2025.06.001
Christian Ingabire, Dao-lun Liang, Li-xiang Li
<div><div>The application of Additive Manufacturing (AM) in the production of solid propellants presents new opportunities to enhance the propulsion performance of rockets, missiles, and space launch vehicles. This review highlights recent progress made in AM of solid propellants using Fused Deposition Modeling (FDM), Direct Ink Writing (DIW), and Stereolithography (SLA) AM methods. These AM methods are set to address limitations of traditional casting techniques by providing rapid prototyping capabilities, greater design flexibility, enhanced manufacturing safety, cost savings, and improved rocket performance.</div><div>Common solid propellant ingredients are examined, with emphasis on recent findings regarding their printability and compatibility with these 3 a.m. processes. The role of thermochemical codes and emerging numerical simulations in predicting propellant material compatibility, performance, and printability is reviewed, alongside important rheological properties essential for solid propellant AM such as material viscosity and yield stress. For each AM method, we also discuss in detail its printing parameters and compatible propellant formulations as well as existing challenges and possible optimization strategies. Furthermore, the mechanical performance and combustion characteristics of additively manufactured solid propellants are thoroughly evaluated.</div><div>Important milestones are discussed in detail, including the successful manufacturing of AP-based propellants by FDM and the development of photocurable binders such as polyester urethane acrylate (PEUA) with comparable ultimate tensile stress to HTPB propellants and six times higher ultimate tensile strain. The possibilities offered by DIW to produce propellants up to 91 wt% solid loading while maintaining structural integrity are also highlighted. Additionally, developments involving SLA method where APNIMMO-based binders have shown stress at break approximately 10 times greater than traditional HTPB, as well as a 480 % increase in burn rate at 100 MPa compared to non-energetic acrylate resins are highlighted.</div><div>Remaining challenges and development trends are discussed, including issues in FDM, such as the incompatibility of certain traditional binders with their thermal conditions, brittleness in some AP-based composites, and difficulties in balancing the addition of metallic materials. DIW faces challenges in managing increased viscosity at high solid and energetic content, leading to manufacturing difficulties and the need for binder system optimization. SLA struggles with maintaining resin transparency, balancing mechanical strength with other properties, optimizing curing parameters, and improving the bonding between matrix and solid particles.</div><div>Future research is expected to focus on developing thermoplastic binders for FDM, exploring energetic copolymer binders and advanced rheological models for DIW, and creating high-energy photopolymer resins whi
{"title":"Progress on additive manufacturing technology of solid propellants","authors":"Christian Ingabire, Dao-lun Liang, Li-xiang Li","doi":"10.1016/j.enmf.2025.06.001","DOIUrl":"10.1016/j.enmf.2025.06.001","url":null,"abstract":"<div><div>The application of Additive Manufacturing (AM) in the production of solid propellants presents new opportunities to enhance the propulsion performance of rockets, missiles, and space launch vehicles. This review highlights recent progress made in AM of solid propellants using Fused Deposition Modeling (FDM), Direct Ink Writing (DIW), and Stereolithography (SLA) AM methods. These AM methods are set to address limitations of traditional casting techniques by providing rapid prototyping capabilities, greater design flexibility, enhanced manufacturing safety, cost savings, and improved rocket performance.</div><div>Common solid propellant ingredients are examined, with emphasis on recent findings regarding their printability and compatibility with these 3 a.m. processes. The role of thermochemical codes and emerging numerical simulations in predicting propellant material compatibility, performance, and printability is reviewed, alongside important rheological properties essential for solid propellant AM such as material viscosity and yield stress. For each AM method, we also discuss in detail its printing parameters and compatible propellant formulations as well as existing challenges and possible optimization strategies. Furthermore, the mechanical performance and combustion characteristics of additively manufactured solid propellants are thoroughly evaluated.</div><div>Important milestones are discussed in detail, including the successful manufacturing of AP-based propellants by FDM and the development of photocurable binders such as polyester urethane acrylate (PEUA) with comparable ultimate tensile stress to HTPB propellants and six times higher ultimate tensile strain. The possibilities offered by DIW to produce propellants up to 91 wt% solid loading while maintaining structural integrity are also highlighted. Additionally, developments involving SLA method where APNIMMO-based binders have shown stress at break approximately 10 times greater than traditional HTPB, as well as a 480 % increase in burn rate at 100 MPa compared to non-energetic acrylate resins are highlighted.</div><div>Remaining challenges and development trends are discussed, including issues in FDM, such as the incompatibility of certain traditional binders with their thermal conditions, brittleness in some AP-based composites, and difficulties in balancing the addition of metallic materials. DIW faces challenges in managing increased viscosity at high solid and energetic content, leading to manufacturing difficulties and the need for binder system optimization. SLA struggles with maintaining resin transparency, balancing mechanical strength with other properties, optimizing curing parameters, and improving the bonding between matrix and solid particles.</div><div>Future research is expected to focus on developing thermoplastic binders for FDM, exploring energetic copolymer binders and advanced rheological models for DIW, and creating high-energy photopolymer resins whi","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 2","pages":"Pages 224-263"},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01DOI: 10.1016/j.enmf.2024.09.006
Gang Wang , Hao Chen , Shi-ying Li , Qi Yang , Yu-dong Shi , Ya-jun Ding , Zhong-liang Xiao
As a new type of gun propellant, Gradiently denitrated spherical gun propellants (GDSP) demonstrate excellent progressive combustion performance and clean combustion performance. However, its unknown storage performance hinders its application, necessitating thorough research. In this study, three types of GDSP samples with different degrees of denitration were prepared using the denitration reaction principle and aging experiments were conducted at different temperatures. SEM and FT-IR characterization revealed changes in the surface microstructure of aged GDSP, while the shape and surface chemical functional groups remained largely unchanged. Oxygen bomb calorimetric method and DSC tests indicated that aging led to a slight decrease in the energy and apparent activation energy of GDSP, as well as a reduction in thermal decomposition stability. Closed vessel tests demonstrated that the maximum dynamic vivacity initially increased and then decreased with prolonged aging, but progressive combustion performance was maintained. Additionally, changes in stabilizer content during aging were assessed using HPLC, determining the safe storage life of GDSP with different degrees of denitration at 30 °C to be 41.9, 62.0 and 81.3 years, respectively. It was concluded that a higher degree of denitration correlates with a longer safe storage life of GDSP. The thermally accelerated aging mechanism of GDSP and the life extension mechanism of denitration treatment are also discussed detailly. These results demonstrate that GDSP possesses excellent storage stability and a long safe storage life, laying the foundation for its application.
{"title":"Storage stability and safe storage life assessments of gradiently denitrated spherical gun propellants","authors":"Gang Wang , Hao Chen , Shi-ying Li , Qi Yang , Yu-dong Shi , Ya-jun Ding , Zhong-liang Xiao","doi":"10.1016/j.enmf.2024.09.006","DOIUrl":"10.1016/j.enmf.2024.09.006","url":null,"abstract":"<div><div>As a new type of gun propellant, Gradiently denitrated spherical gun propellants (GDSP) demonstrate excellent progressive combustion performance and clean combustion performance. However, its unknown storage performance hinders its application, necessitating thorough research. In this study, three types of GDSP samples with different degrees of denitration were prepared using the denitration reaction principle and aging experiments were conducted at different temperatures. SEM and FT-IR characterization revealed changes in the surface microstructure of aged GDSP, while the shape and surface chemical functional groups remained largely unchanged. Oxygen bomb calorimetric method and DSC tests indicated that aging led to a slight decrease in the energy and apparent activation energy of GDSP, as well as a reduction in thermal decomposition stability. Closed vessel tests demonstrated that the maximum dynamic vivacity initially increased and then decreased with prolonged aging, but progressive combustion performance was maintained. Additionally, changes in stabilizer content during aging were assessed using HPLC, determining the safe storage life of GDSP with different degrees of denitration at 30 °C to be 41.9, 62.0 and 81.3 years, respectively. It was concluded that a higher degree of denitration correlates with a longer safe storage life of GDSP. The thermally accelerated aging mechanism of GDSP and the life extension mechanism of denitration treatment are also discussed detailly. These results demonstrate that GDSP possesses excellent storage stability and a long safe storage life, laying the foundation for its application.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 2","pages":"Pages 212-223"},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01DOI: 10.1016/j.enmf.2025.02.002
Liang-liang Lv , Wei-bin Zhang , Xiao-dong Pan , Gong-ping Li , Cui Zhang
Polymer bonded explosive (PBX) is a composite explosive mainly made up of explosive crystals and binders. The presence of cracks and impurities within PBX impacts its mechanical properties and detonation performance. The highly filled granular nature and heterogeneous characteristics of PBX's internal structure, combined with the low contrast and small proportion of defects in PBX, present significant challenges for the precise segmentation and quantification of internal defects in PBX. In this paper, we proposed PBX_SegNet for PBX defect segmentation based on convolutional neural network. The PBX_SegNet is built on the encoder–decoder architecture of U-Net. We optimize the structure of skip connection in PBX_SegNet and introduce a concurrent spatial and channel squeeze and excitation (SCSE) module on each stage in the encoder network and in the decoder network. We train and evaluate PBX_SegNet on PBX defect dataset which consists of images acquired by micro computed tomography (μCT). Using the same test dataset, the proposed method was compared and evaluated against four mainstream segmentation methods based on deep learning. The results demonstrate that PBX_SegNet realizes the simultaneous segmentation of PBX cracks and impurities, and further completes the quantitative characterization of PBX cracks and impurities by processing the segmentation results using image processing methods. PBX_SegNet achieves Dice score (DICE) of 0.9965, crack relative area (RAC) of 0.9033 and impurity relative area (RAI) of 0.9511 on the three PBX defect datasets in average, which outperforms the current four state-of-the-art methods and improves the low contrast and small proportion of defect segmentation and quantification characterization capabilities. The proposed method shows promise for segmenting subtle, low-contrast defects in images from various domains or imaging techniques.
{"title":"PBX micro defect characterization by using deep learning and image processing of micro CT images","authors":"Liang-liang Lv , Wei-bin Zhang , Xiao-dong Pan , Gong-ping Li , Cui Zhang","doi":"10.1016/j.enmf.2025.02.002","DOIUrl":"10.1016/j.enmf.2025.02.002","url":null,"abstract":"<div><div>Polymer bonded explosive (PBX) is a composite explosive mainly made up of explosive crystals and binders. The presence of cracks and impurities within PBX impacts its mechanical properties and detonation performance. The highly filled granular nature and heterogeneous characteristics of PBX's internal structure, combined with the low contrast and small proportion of defects in PBX, present significant challenges for the precise segmentation and quantification of internal defects in PBX. In this paper, we proposed PBX_SegNet for PBX defect segmentation based on convolutional neural network. The PBX_SegNet is built on the encoder–decoder architecture of U-Net. We optimize the structure of skip connection in PBX_SegNet and introduce a concurrent spatial and channel squeeze and excitation (SCSE) module on each stage in the encoder network and in the decoder network. We train and evaluate PBX_SegNet on PBX defect dataset which consists of images acquired by micro computed tomography (μCT). Using the same test dataset, the proposed method was compared and evaluated against four mainstream segmentation methods based on deep learning. The results demonstrate that PBX_SegNet realizes the simultaneous segmentation of PBX cracks and impurities, and further completes the quantitative characterization of PBX cracks and impurities by processing the segmentation results using image processing methods. PBX_SegNet achieves Dice score (<em>DICE</em>) of 0.9965, crack relative area (<em>RA</em><sub><em>C</em></sub>) of 0.9033 and impurity relative area (<em>RA</em><sub><em>I</em></sub>) of 0.9511 on the three PBX defect datasets in average, which outperforms the current four state-of-the-art methods and improves the low contrast and small proportion of defect segmentation and quantification characterization capabilities. The proposed method shows promise for segmenting subtle, low-contrast defects in images from various domains or imaging techniques.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 2","pages":"Pages 177-188"},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01DOI: 10.1016/j.enmf.2025.05.001
Qing-guan Song , Li Meng , Sheng-li Jiang , Lei Zhang , Ze-yao Mo
The cage-like structures provide a unique combination of strain energy for enhanced energy storage and hyperstatic constraints to stabilize the system, positioning them as promising pioneers in advancing high-energy-density materials (HEDMs). However, the shock response of cage-like HEDMs is highly complex and exhibits significant variability, posing a grand challenge in the underlying mechanisms. This study reveals that the shock response of cage-like HEDMs is regulated by the interplay between strain energy and structural symmetry, and introduces a physical model to quantitatively describe how they determine shock stability. The investigated systems include a comprehensive series of cage-like polynitrocubane HEDMs, with each carbon atom in the backbone progressively functionalized with nitro groups. Ab initio molecular dynamics (AIMD) simulations were employed to simulate dynamic and kinetic responses at shock velocities ranging from 8 km·s−1 to 11 km·s−1, with validation provided by consistent Hugoniot curves that align with reported experimental data. Nitro groups at the carbon-based cage structure, recognized as explosion functional groups, were found to substantially increase the system's strain energy. However, an increasing number of nitro groups also intensified electrostatic repulsion among oxygen lone pairs, which weakens structural integrity and renders the material more susceptible to disassembly under shock conditions. Conversely, structural symmetry—including both the cage-like molecular conformation and spatial packing within the crystal lattice—was found to mitigate these destabilizing effects, effectively balancing the trade-off between energy storage and structural stability. Based on these findings, we propose a physical model that captures the essential factors driving shock initiation in cage-like polynitrocubane HEDMs, offering new insights to inform the design and application of novel advanced HEDMs.
{"title":"Shock response in cage-like polynitrocubane high-energy-density materials: Competition between strain energy and structural symmetry","authors":"Qing-guan Song , Li Meng , Sheng-li Jiang , Lei Zhang , Ze-yao Mo","doi":"10.1016/j.enmf.2025.05.001","DOIUrl":"10.1016/j.enmf.2025.05.001","url":null,"abstract":"<div><div>The cage-like structures provide a unique combination of strain energy for enhanced energy storage and hyperstatic constraints to stabilize the system, positioning them as promising pioneers in advancing high-energy-density materials (HEDMs). However, the shock response of cage-like HEDMs is highly complex and exhibits significant variability, posing a grand challenge in the underlying mechanisms. This study reveals that the shock response of cage-like HEDMs is regulated by the interplay between strain energy and structural symmetry, and introduces a physical model to quantitatively describe how they determine shock stability. The investigated systems include a comprehensive series of cage-like polynitrocubane HEDMs, with each carbon atom in the backbone progressively functionalized with nitro groups. <em>Ab initio</em> molecular dynamics (AIMD) simulations were employed to simulate dynamic and kinetic responses at shock velocities ranging from 8 km·s<sup>−1</sup> to 11 km·s<sup>−1</sup>, with validation provided by consistent Hugoniot curves that align with reported experimental data. Nitro groups at the carbon-based cage structure, recognized as explosion functional groups, were found to substantially increase the system's strain energy. However, an increasing number of nitro groups also intensified electrostatic repulsion among oxygen lone pairs, which weakens structural integrity and renders the material more susceptible to disassembly under shock conditions. Conversely, structural symmetry—including both the cage-like molecular conformation and spatial packing within the crystal lattice—was found to mitigate these destabilizing effects, effectively balancing the trade-off between energy storage and structural stability. Based on these findings, we propose a physical model that captures the essential factors driving shock initiation in cage-like polynitrocubane HEDMs, offering new insights to inform the design and application of novel advanced HEDMs.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 2","pages":"Pages 145-155"},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01DOI: 10.1016/j.enmf.2024.06.006
Chun-jie Zuo, Chao-yang Zhang
Differential scanning calorimetry (DSC) test is capable of providing comprehensive data of peak temperature (, K) and onset temperature (, K) at various heating rates (β) and widely applied in the thermal safety assessment of energetic materials (EMs). However, and () are variable, depending on β, making inconvenience and confusion in thermal stability of different EMs, in particular, in the case of testing conditions absent. This study aims to standardize at various β to as a threshold temperature of thermal decomposition. It is confirmed that Pow2P2 (two-parameter power function) is feasible to fit the relationship by any two experimental points, and extrapolate . Thereby, , as a single value of DSC test of one EM, benefits for thermal stability study.
{"title":"Standardizing differential scanning calorimetry (DSC) thermal decomposition temperatures at various heating rates of an energetic material as a threshold one","authors":"Chun-jie Zuo, Chao-yang Zhang","doi":"10.1016/j.enmf.2024.06.006","DOIUrl":"10.1016/j.enmf.2024.06.006","url":null,"abstract":"<div><div>Differential scanning calorimetry (DSC) test is capable of providing comprehensive data of peak temperature (<span><math><mrow><msub><mi>T</mi><mi>p</mi></msub></mrow></math></span>, K) and onset temperature (<span><math><mrow><msub><mi>T</mi><mi>o</mi></msub></mrow></math></span>, K) at various heating rates (<em>β</em>) and widely applied in the thermal safety assessment of energetic materials (EMs). However, <span><math><mrow><msub><mi>T</mi><mi>p</mi></msub></mrow></math></span> and <span><math><mrow><msub><mi>T</mi><mi>o</mi></msub></mrow></math></span> (<span><math><mrow><msub><mi>T</mi><mrow><mi>p</mi><mo>/</mo><mi>o</mi></mrow></msub></mrow></math></span>) are variable, depending on <em>β</em>, making inconvenience and confusion in thermal stability of different EMs, in particular, in the case of testing conditions absent. This study aims to standardize <span><math><mrow><msub><mi>T</mi><mrow><mi>p</mi><mo>/</mo><mi>o</mi></mrow></msub></mrow></math></span> at various <em>β</em> to <span><math><mrow><msub><mi>T</mi><mrow><mi>p</mi><mo>/</mo><mi>o</mi><mo>,</mo><mi>β</mi><mo>→</mo><mn>0</mn></mrow></msub></mrow></math></span> as a threshold temperature of thermal decomposition. It is confirmed that <em>Pow2P2</em> (two-parameter power function) is feasible to fit the <span><math><mrow><msub><mi>T</mi><mrow><mi>p</mi><mo>/</mo><mi>o</mi></mrow></msub><mo>−</mo><mi>β</mi></mrow></math></span> relationship by any two experimental points, and extrapolate <span><math><mrow><msub><mi>T</mi><mrow><mi>p</mi><mo>/</mo><mi>o</mi><mo>,</mo><mi>β</mi><mo>→</mo><mn>0</mn></mrow></msub></mrow></math></span>. Thereby, <span><math><mrow><msub><mi>T</mi><mrow><mi>p</mi><mo>/</mo><mi>o</mi><mo>,</mo><mi>β</mi><mo>→</mo><mn>0</mn></mrow></msub></mrow></math></span>, as a single value of DSC test of one EM, benefits for thermal stability study.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 2","pages":"Pages 189-194"},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01DOI: 10.1016/j.enmf.2025.03.005
Xiang-yu Meng , Lei Zhang , Hai-ying Wang , Lan-hong Dai
Energetic high-entropy alloys (HEAs), known for their exceptional mechanical properties and high energy density attributes, have attracted significant attention in energetic structure materials. However, these alloys typically operate under shock loadings, and the induced phase transitions occur at ultra-high strain rates, surpassing the resolution capabilities of current experimental equipment. The interplay of varying elemental compositions and short-range order further complicates the phase transitions, leaving the underlying mechanisms poorly understood. In this study, hybrid molecular dynamics and Monte Carlo (MD/MC) simulations were conducted to investigate the atomistic mechanism of shock-induced phase transitions in a prototypical energetic HEA Hfx(NbTaTiZr)(1-x), considering variations in Hf element contents and degrees of chemical short-range order (CSRO). It was found that shocked HfNbTaTiZr undergoes a structural transition from its initial body-centered cubic (BCC) phase to a hexagonal close-packed (HCP) phase. This transition was predominantly facilitated by the decrease in atomic spacing along the shock direction, an increase in atomic spacing perpendicular to it, and the slip of certain ( 10) planes along the [ 0] crystallographic direction. The shock velocity thresholds of HCP nucleation and growth were determined to be 230 m s−1 and 280 m s−1, respectively. An increase in Hf content lowered the threshold for the BCC to HCP phase transition, while CSRO reduced the nucleation threshold of HCP but increased the growth threshold. Finally, a physical model was developed to quantify the interplay between Hf content and CSRO in regulating the initiation and evolution of phase transition in shocked Hfx(NbTaTiZr)(1-x). These findings will shed new light on the understanding of shock-induced phase transitions in energetic metallic materials.
高能高熵合金（HEAs）以其优异的力学性能和高能量密度特性，在高能结构材料中备受关注。然而，这些合金通常在冲击载荷下工作，并且在超高应变速率下发生诱导相变，超出了当前实验设备的分辨率能力。不同元素组成和短程顺序的相互作用使相变进一步复杂化，使人们对潜在的机制知之甚少。在本研究中，采用混合分子动力学和蒙特卡罗（MD/MC）模拟研究了典型高能HEA Hfx(NbTaTiZr)（1-x）中激波诱导相变的原子机制，考虑了Hf元素含量和化学短程有序度（CSRO）的变化。研究发现，受冲击的HfNbTaTiZr经历了从初始体心立方（BCC）相到六方密堆积（HCP）相的结构转变。这种转变主要是由沿激波方向原子间距的减小，垂直于它的原子间距的增加，以及沿[1 - 1 - 1 - 0]晶体方向的某些（1 - 10）平面的滑动所促进的。HCP成核和生长的冲击速度阈值分别为230 m s - 1和280 m s - 1。Hf含量的增加降低了BCC向HCP相变的阈值，而CSRO降低了HCP的成核阈值，但提高了HCP的生长阈值。最后，建立了一个物理模型来量化Hf含量和CSRO在调节激波Hfx（NbTaTiZr）相变的开始和演变中的相互作用（1-x）。这些发现将对高能金属材料中冲击诱导相变的理解提供新的线索。
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