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Performance and Mechanisms of P–N Synergistic Oligomeric Flame Retardants with Different Phosphorus Oxidation States in Epoxy Resin

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ChemistrySelect 2025年第21期10卷

作者： Yujie Chen Qiu Shi Jinlei Liu Haojie Mei Weiyin Wang Chuanxi Xiong Shan Wang Yilin Tang Shipeng Zhu School of Materials Science and Engineering Wuhan University of Technology Wuhan 430070 China Hubei Engineering Research Center for Green Precision Material Forming Wuhan 430070 China Key Laboratory of Advanced Functional Composite Materials Aerospace Research Institute of Materials and Processing Technology Beijing 100076 China

Flame retardancy is essential for epoxy resins (EP) used in safety-critical applications. Although phosphorus-based flame retardants have shown effectiveness, most studies have focused on small-molecule systems, with limited attention on their oligomeric counterparts. In this study, two phosphorus-nitrogen synergistic oligomeric flame retardants with different phosphorus oxidation states—TEPP (+III) and TEPP (+V)—were synthesized and incorporated into EP. The results indicated that, when TEPP and TEOPP were added at a concentration of 5 wt%, the limiting oxygen index (LOI) values of EP/TEPP and EP/TEOPP were 35.6% and 32.6%, respectively, with the former achieving a UL-94 V0 rating. Cone calorimeter tests demonstrated that EP/TEOPP outperformed EP/TEPP in reducing heat and smoke release, suggesting distinct flame-retardant mechanisms: TEPP primarily acts in the gas phase via the release of phosphorus-containing radicals, while TEOPP promotes char formation in the condensed phase. Both systems also demonstrated good mechanical performance, owing to the hydroxyl groups and branched structures in the flame retardant molecules. This work provides valuable insight into the structure–property relationships of phosphorus–nitrogen oligomers and offers a strategy for designing high-performance flame-retardant epoxy systems.

关键词： Epoxy resin Flame retardancy Oligomers Oxidation states P─N synergism

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Effects of composition and natural ageing on microstructure and mechanical properties of Al-Mg-Si heat treatment-free die-cast alloys assisted with machine learning

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Materials Today Communications 2025年 47卷

作者： Jinpeng Sun Xixi Dong Shenghui Li Hailin Yang Shouxun Ji College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China State Key Laboratory of Advanced Forming Technology & Equipment Nanjing University of Aeronautics and Astronautics Nanjing 210016 China State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China Brunel Centre for Advanced Solidification Technology (BCAST) Brunel University London Uxbridge UB8 3PH United Kingdom

The microstructure and tensile properties of Al-(5.5–7.0)Mg-(2.0–3.0)Si (wt%) die-cast alloys were studied in the as-cast state and after natural ageing for 14, 30 and 90 days. In the as-cast microstructure, the primary Al, fibrous eutectic Mg 2 Si and small blocky intermetallic α-Al 15 (Fe,Mn) 3 Si 2 phases were identified. As Mg and Si increased, the volume fraction of the Mg 2 Si increased, while the Mg 2 Si fibre spacing decreased. In the as-cast state, the representative Al5.5Mg2Si and Al7Mg3Si alloys exhibited the yield strength (YS) of 163 ± 2.6 MPa and 180 ± 4 MPa, ultimate tensile strength (UTS) of 313 ± 3.9 MPa and 332 ± 14.2 MPa and elongation (El) of 13 ± 1.17 % and 7 ± 1.91 %. The mechanism of the higher strength of Al7Mg3Si compared to Al5.5Mg2Si is the increased volume fraction of Mg 2 Si and the reduced fibre spacing of Mg 2 Si by 0.15μm. After natural ageing for 90 days, the representative Al5.9Mg2.6Si and Al7Mg3Si alloys exhibited the YS improvement of 22.6 MPa and 8.7 MPa and the absolute decrease of El by 1.32 % and 0.9 %. The mechanism of the further strengthening after natural ageing is the formation of β'' nanoscale precipitates. An adaptive boosting machine learning model was utilized to establish a quantitative relationship among composition, natural ageing, and tensile performance, and the YS after natural ageing for 90 days conforms to the relationship of YS ( MPa ) = 192.3 − 73.1 e − x Mg 2.4 − x Si 13.9 . A high strength and ductility Al6Mg2.5Si alloy was predicted with the YS, UTS and El of 184 ± 2.5 MPa, 329 ± 6.1 MPa and 10 ± 1.54 % after natural ageing for 90 days. This work offers an intelligent path for designing high-performance die-cast alloys.

关键词： Aluminium alloys Machine learning Mechanical properties Microstructure Natural ageing

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(Ti, Ta)C-(Ti, Ta)B 2 -SiC based ceramics with core-rim structure by in-situ reaction sintering at low temperature: Formation mechanism and enhanced mechanical properties

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Journal of Materials Science & technology 2025年

作者： Liwei Wang Boxin Wei Dong Wang Lei Chen Yujin Wang School of Materials Science and Chemical Engineering Harbin University of Science and Technology Harbin 150040 China Heilongjiang Provincial Key Laboratory of Light Metal Materials Modification and Green Forming Technology Harbin University of Science and Technology Harbin 150040 China School of Materials Science and Engineering Anhui University of Technology Ma’anshan 243002 China Institute for Advanced Ceramics School of Materials Science and Engineering Harbin Institute of Technology Harbin 150080 China Key Laboratory of Advanced Structural-Functional Integration Materials & Green Manufacturing Technology Harbin Institute of Technology Harbin 150001 China

A novel method for fabricating “core-rim” structured toughened (Ti, Ta)C-(Ti, Ta)B 2 -SiC based ceramics was developed, employing in-situ reaction hot-pressing of TiC, TaB 2 , and Si powders at 1600°C. This study explored the impact of varying TaB 2 and Si concentrations on the microstructure and mechanical properties of the ceramics and clarified the formation mechanism of the “core-rim” structure. In this process, the reaction process of TiC and TaB 2 powders and the reaction and solid solution formation of (Ti, Ta)C and (Ti, Ta)B 2 occur simultaneously. TiC/TaC react with Si to form (Ta, Ti)Si 2 and β-SiC phases through further solid solution reactions. The presence of β-SiC and (Ta, Ti)Si 2 , coupled with low-temperature in-situ reactions, restricts grain growth and refines the microstructure. Adding 10 mol% TaB 2 results in incomplete diffusion of TaC in TiC, leading to the distinct “core-rim” structure, with cracks propagating preferentially along the rim. The β-SiC and plate-like (Ti, Ta)B 2 structures formed in-situ reactions significantly enhance the fracture toughness of the ceramics. The TiC-32 mol% Si-10 mol% TaB 2 (10TB-16) exhibited superior fracture toughness of 6.97±0.52 MPa m 1/2 , the TiC-16 mol% Si-30 mol% TaB 2 (30TB-16) exhibited superior flexural strength of 835±39 MPa, excellent fracture toughness of 6.68±0.66 MPa m 1/2 , offering new insights into optimizing the strength and toughness of ceramics.

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The pitting corrosion mechanism in additively manufactured Ni over-alloyed 22Cr duplex stainless steel at different temperatures

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Construction and Building Materials 2025年 486卷

作者： Zhiyuan Huang Yiqi Zhou Lili Li Decheng Kong Shuoyang Wang Zhuangzhuang Liu Xiaogang Li Chaofang Dong Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing 100083 China Shunde Innovation School University of Science and Technology Beijing Shunde 528399 China Laboratory of Advanced Materials of Ministry of Education School of Materials Science and Engineering Tsinghua University Beijing 100084 China School of Advanced Materials Innovation Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology Beijing China Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

Laser powder bed fusion (LPBF) produced type 2205 duplex stainless steel (DSS) exhibited a nearly fully ferritic microstructure due to rapid solidification. In this study, nickel alloy and DSS 2205 powder were blended as raw materials to fabricate LPBF 22Cr DSS with an austenite content exceeding 20 %. However, variations in microstructure along different build directions resulted in disparities in pitting corrosion resistance. In 0.6 M NaCl solution, the critical pitting potentials ( E pit ) of the XOZ and YOZ planes were 190 mV and 77 mV higher, respectively, than that of the XOY plane at 60 °C and 70 °C. Conversely, when the electrolyte temperature increased to 80 °C, the XOY plane displayed a 150 mV higher E pit compared to the XOZ and YOZ planes. Potentio-static pulse testing (PPT) revealed two distinct pitting nucleation sites on the XOY plane, with three preferred nucleation sites were observed on the YOZ and XOZ planes across the temperature range of 60–80 °C. The driving force for pit nucleation was influenced by electrolyte temperature, leading to a shift in E pit values: the XOY plane exhibited the lowest E pit at 60 °C and 70 °C, then became the highest at 80 °C.

关键词： Duplex stainless steel Laser powder bed fusion Mixed raw materials Pitting corrosion

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A coupled model of rolling process based on approximate rigid body model

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International Journal of Mechanical Sciences 2025年 300卷

作者： Zhiqiang Li Tao Wang Chenchen Zhao Baoqi Guo Zhongkai Ren Zhengyi Jiang Qingxue Huang College of Mechanical Engineering Taiyuan University of Technology Taiyuan 030024 China Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment Ministry of Education Taiyuan 030024 China National Key Laboratory of Metal Forming Technology and Heavy Equipment Xi 'an 710000 China School of Mechatronics Engineering Harbin Institute of Technology Harbin 150006 China School of Mechanical Materials Biomedical and Mechatronic Engineering University of Wollongong NSW 2522 Australia

Rolling is a rapid and efficient metal forming technique with vast potential for future applications. Concurrently, the finite element method (FEM) has become a standard tool for analyzing the rolling process. Typically, two models are employed for the rolls during this analysis: the rigid body model and the elastic body model. However, employing a rigid body model reduces computational accuracy, while using an elastic body model results in lower computational efficiency. To address this issue, this study developed an approximate rigid body model. This model dynamically adjusts the displacement of the roll nodes within the rolling zone to ensure that the shape of the flattened roll remains consistent throughout the rolling process. This model accounts for roll flattening while avoiding the extensive computational time typically required to solve for roll deformation. In order to address the coupled deformation issues between roll deformation and plate deformation, a coupled model based on the approximate rigid body model has been established. This coupled model utilizes the FEM to calculate the deformation of the plate as well as the associated rolling force. Subsequently, the shape of the roll is updated in accordance with this force, and the plate's deformation is recalculated. This process is iteratively repeated until the rolling force converges to a predetermined standard. Upon verification, the proposed coupled model demonstrates excellent convergence. The results obtained using the coupled model closely align with those derived from the finite element model employing elastic rolls. Compared to experimental measurements, the prediction errors for both the rolling force and the plate thickness are within 3 %. The coupled model offers a novel approach for rapidly and efficiently solving the deformation of die and workpieces in metal forming processes.

关键词： Approximate rigid body Coupled model FEM Neutral point Roll flattening Rolling

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Experimental study on battery thermal management performance of expanded graphite/paraffin/Si 3 N 4 composite phase change material for cylindrical 21,700 Li-ion battery

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Applied Thermal Engineering 2025年 276卷

作者： Jian Liu Songyi You Xin Ge Bihui Chen Dahai Zeng Yanfeng Li Muchao Qu Junjie Yu Kun Shan Shuaibo Zeng Kai Zhuo Xuntao Xie School of Automobile and Transportation Engineering Guangdong Polytechnic Normal University Guangzhou 510665 China Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Metallic Materials South China University of Technology Guangzhou 510640 China Institute of Advanced Wear & Corrosion Resistant and Functional Materials Jinan University Guangzhou 510632 China

Phase change material (PCM)-based battery thermal management systems (BTMs) have emerged as an effective cooling solution by utilizing the latent heat absorption/release mechanism of PCMs, offering significant advantages in thermal buffering and battery lifespan extension. This study presents a novel thermally-enhanced composite phase change material (CPCM) composed of paraffin (PA), expanded graphite (EG), and silicon nitride (Si 3 N 4 ). Structural characterization through X-ray diffraction (XRD) and scanning electron microscopy (SEM) of different Si 3 N 4 mass fractions (0-15 wt%) CPCMs confirmed excellent physicochemical compatibility among all components in the prepared CPCMs. The optimal composition with 3 wt% Si 3 N 4 demonstrated superior thermal performance, making it particularly suitable for battery cooling applications. The CPCM effectively reduced thermal contact resistance when embedded in batteries, thereby significantly enhancing thermal regulation performance. Comparative experiments showed that the Si 3 N 4 -enhanced CPCM maintained the maximum temperature (T max ) at 47.6 °C with a maximum temperature differential (ΔT max ) within 3.3 °C at 3C discharge rate under 35 °C ambient conditions. Compared with natural air cooling, the T max and ΔT max decreased 30.6 % and 74.2 %, respectively. Remarkably, after six consecutive charge–discharge cycles at 3C rate, the T max still remained as low as 49.9 °C within the ideal work temperature range. These findings demonstrate that the developed CPCM exhibits outstanding potential for thermal energy storage applications, with significant implications for both academic research and industrial implementation in advanced battery thermal management systems.

关键词： Lithium-ion batteries

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Dynamic Modeling Method of Spatial Passive Over-constrained Parallel Mechanism Based on Newton Euler Method

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Jixie Gongcheng Xuebao/Journal of Mechanical Engineering 2020年第11期56卷 48-57页

作者： Li, Yongquan Guo, Yu Zhang, Yang Zhang, Lijie Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University Ministry of Education of China Qinhuangdao066004 China Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Qinhuangdao066004 China

The 4-RPTR four-degree-of-freedom space passive over-constrained (redundant constrained) parallel mechanism is taken as the research object, and the Newton Euler method combined with the complementary deformation coordination equation is used to analyze the dynamics. The number of dynamic equations based on Newton's Euler method is 78, but due to the existence of passive over-constraints of the mechanism, the unknown variables of the required solutions are 80. When the eight deformation coordination equations are added according to the method of planar over-constrained mechanism, it will be linearly related to the 78 equations built, resulting in the equations being unable to solve. Based on this, when proposing the dynamics modeling of passive over-constrained parallel mechanism, the reason for the passive over-constraint of the mechanism should be analyzed firstly. On this basis, adding the deformation of the member caused by the redundant constrained force (torque) and the position and posture error of the terminal platform as a complementary equation ensures that the equations are linearly independent and can be solved. To this end, the relationship between the deformation of the rod and the position and posture error of the terminal platform caused by the rotational joint restraining torque directly causing the redundant constraint is introduced, and eight deformation coordination equations are added, and six unknown variables are introduced, thereby obtaining 86 equations. Containing 86 unknowns, and the equations are linearly independent, the dynamic solution model of the mechanism is obtained. Based on matlab and adams software, the dynamics simulation of the mechanism is carried out. When the same motion trajectory is given at the terminal of the platform, the correctness of the dynamic model can be seen by comparing the driving force variation curves of the two methods. It provides a new idea for dynamic modeling of this type of space passive over-constrai

关键词： Dynamics

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Microstructures and Mechanical Properties of a new high entropy alloy

Microstructures and Mechanical Properties of a new high entr...

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作者： Mingju Chen Jing Yang School of Resources and Materials Northeastern University at Qinhuangdao Key Laboratory of advanced metal materials and forming technology in Qinhuangdao Northeastern University at Qinhuangdao State Key Laboratory of Metastable Materials Science and Technology Yanshan University

All manuscripts must be in English, also the table and figure texts, otherwise we cannot publish your paper. Please keep a second copy of your manuscript in your office. When receiving the paper, we assume that the corresponding authors grant us the copyright to use the paper for the book or journal in question. Should authors use tables or figures from other Publications, they must ask the corresponding publishers to grant them the right to publish this material in their paper.

关键词： Microstructures and Mechanical Properties of a new high entropy alloy

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Microstructure and high-temperature wear behavior of TiZrNbAl x light-weight refractory high-entropy alloy coatings prepared by laser cladding on Ti6Al4V titanium alloy

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Surface and Coatings technology 2025年 512卷

作者： Yaxia Liu Hongxi Liu Yang Chen Ming Wen Ben Niu Xiaowei Zhang Haifang Liu The Faculty of Materials Science and Engineering Kunming University of Science and Technology Kunming 650093 China National-local Joint Engineering Research Center for Technology of Advanced Metallic Solidification Forming and Equipment Kunming 650093 PR China State Key Laboratory of Precious Metal Functional Materials Kunming Institute of Precious Metals Kunming 650106 China China-Ukraine Institute of Welding Guangdong Academy of Sciences Guangdong Provincial Key Laboratory of Material Joining and Advanced Manufacturing Guangzhou 510650 China

The TiZrNbAl x (x = 0.1, 0.2, 0.3) light-weight refractory high-entropy alloys coatings were fabricated on the Ti6Al4V titanium alloy by laser cladding technology. The effect of Al content on the microstructure and wear behavior of the coatings were investigated. All coatings were composed of the BCC phase and a few Zr-rich phase. The grains were refined as the Al content increased, and the Zr-rich phase increased. The TiZrNbAl 0.3 exhibited the best wear resistance at room temperature and 500 °C. Compared to Ti6Al4V, the wear rate of TiZrNbAl 0.3 decreased by 48.54 % and 15.7 % at room temperature and 500 °C, respectively. Molecular dynamics simulations were used to study the wear behavior of TiZrNbAl 0.3 coating at different temperatures, and the results showed that the thermal vibrations and random motion of the interface atoms are enhanced at 500 °C, weakening the crystalline characteristics of the interface, promoting strain accumulation in the TiZrNbAl 0.3 coating, and further worsening the material wear. As a result, the wear resistance of the coatings at 500 °C is lower than at room temperature.

关键词： Thermal fatigue

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Influence of liquid film thickness on bearing characteristics of magnetic-liquid suspension guide-way

Influence of liquid film thickness on bearing characteristic...

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19th International Conference of Fluid Power and Mechatronic Control Engineering 2018

作者： Zhao, Jianhua Zhang, Bin Chen, Tao Wang, Qiang Gao, Dianrong Key Laboratory of Advanced Forging and Stamping Technology and Science Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Qinhuangdao066004 China

The magnetic-liquid suspension guide-way (MLSG) adopts the double support form of permanent magnetic suspension and hydrostatic pressure. It can greatly enhance the bearing capacity and rigidity of the guide-way system. The liquid film thickness is the main influencing factor on both the bearing capacity of the hydrostatic system and the permanent magnetic force. This paper analysed the effect of liquid film thickness on the static, dynamic and vibration index of MLSG. Firstly, this paper introduced the structural characteristics and supporting mechanism of MLSG. Secondly, based on flow equation, the static pressure equation, the permanent magnetic force equation and the force balance equation, the transfer function of single DOF supporting system of MLSG in constant flow supply mode is presented, and analysed the influence of the thickness of liquid film on single DOF supporting performance of MLSG. The results show that with the increase of the thickness of the liquid film, the bearing capacity of guide-way, the static stiffness, the dynamic stiffness and the natural frequency decrease, and the adjust time, the total power loss, the amplitude amplification coefficient increases, the phase margin is almost unchanged. The study can provide a theoretical basis for the design of MLGS in engineering practice. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Bearing capacity

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