关键词： 玻璃纤维增强聚酰胺6   二乙基次膦酸铝(ADP)   三聚氰胺衍生物   阻燃性能   力学性能  

摘要： 以二乙基次膦酸铝(ADP)为主阻燃剂,三聚氰胺聚磷酸盐(MPP)、三聚氰胺氰尿酸盐(MCA)为协效阻燃剂用于玻璃纤维增强聚酰胺6复合材料(PA6/GF)的阻燃改性。研究结果表明:与MCA相比,MPP与ADP的复配能发挥更好的协效阻燃作用,其中当总阻燃剂的添加量为10%(如无特殊说明,均为质量分数)、ADP与MPP复配的质量比为8∶1时,PA6/GF/ADP∶MPP(8∶1)阻燃复合材料垂直燃烧等级能够通过UL-94 V-1级,极限氧指数值(LOI)达到29.7%。与PA6/GF/ADP复合材料相比,PA6/GF/ADP∶MPP(8∶1)阻燃复合材料的热释放速率峰值(pk-HRR)和总热释放量(THR)分别降低至307.6 kW/m^(2)和154.6 MJ/m^(2),分别下降了3.6%和6.4%,且锥形量热测试的残炭量高达40.6%,这表明MPP能够提升阻燃体系在凝聚相中的阻燃效果。此外,MPP的引入有利于提升复合材料的拉伸强度,与PA6/GF/ADP复合材料相比,PA6/GF/ADP∶MPP(8∶1)的拉伸强度提升了17.6%。

关键词： Corrosion resistance  

摘要： Fiber-reinforced resin matrix composites (FRC) are extensively utilized in sectors such as aerospace, rail transportation, and wind energy due to their exceptional properties, including high specific strength, corrosion resistance, and cost-effectiveness. However, during the molding process, these composites undergo complex physical and chemical transformations that inevitably lead to the formation of internal defects. Notably, the rapid thermal cycling associated with additive manufacturing (AM) processes further escalates the likelihood of defect formation. Consequently, research into manufacturing defects and online monitoring is crucial for enhancing the quality of FRC produced through additive manufacturing. This study provides an in-depth summary of the mechanisms behind the formation of defects within the resin matrix of composites, including residual stress, porosity, resin-rich areas, and interfacial defects. It analyzes the impact of these defects on the macroscopic mechanical properties of the composites and elucidates the micro-level origins of each defect type. Subsequently, the paper consolidates online detection techniques based on Fiber Bragg Grating (FBG) sensors, strain and displacement sensors, acoustic emission technology, and thermodynamic monitoring. It discusses the technical characteristics, application scenarios, and limitations of these techniques, aiming to offer insights and references for scientific research in this field. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： distal femoral replacement   internal fixation   osteosynthesis   periprosthetic fracture   revision TKA   distal femur  

摘要： Biodegradable Mg-based materials have emerged as a promising class of orthopedic implants in the 21st century, owing to their excellent osteogenic properties and an elastic modulus similar to that of cortical bone. This review summarizes the current applications and development trends of Mg- based composites in bone repair. First, the fabrication methods of Mg-based composites, along with their advantages and disadvantages, are discussed. Second, the impact of reinforcement on the mechanical properties and degradation behavior of these composites is examined. Third, preclinical studies on the use of Mg-based composites in fracture fixation and bone defect repair are reviewed, confirming their bioactivity and clinical safety. Fourth, the effects of the degradation behavior of Mg-based composites on stem cell osteogenic differentiation and the related molecular mechanisms are explored. Finally, the challenges of applying Mg-based composites for bone repair based on existing preclinical studies are outlined, and potential future advancements are proposed.

关键词： Flame resistance  

摘要： Polymeric materials are inherently flammable and prone to oxidation. Traditional intumescent flame retardants exhibit drawbacks, including significant moisture absorption, limited flame-retardant efficacy, and suboptimal matrix compatibility. To address these challenges, a trinity intumescent flame retardant (PTA-PA) was synthesized, integrating the principles of gas-phase and condensed-phase flame retardation. This study examined the influence of varying PTA-PA concentrations on the flame resistance and mechanical properties of polyurea (PUA). It entailed analyzing combustion and pyrolysis byproducts to elucidate the mechanism of flame retardance provided by these novel agents. Additionally, the study correlated the introduction of PTA-PA with enhancements in thermal stability, flame retardance, and overall fire safety of the composites. The findings indicate that the PUA composite with a 20.0wt% loading of PTA-PA (PUA-4) exhibits increased thermal stability, evidenced by a residual carbon content of 21.9% at 800℃. Notably, the vertical burn rating of PUA-4 improved from V-2 to V-0, the limiting oxygen index (LOI) rose from 22.2% to 28.4%, and the rates of line ablation, peak heat release, and total heat release diminished by 19.8%, 71.7% and 18.3%, respectively. This investigation provides a theoretical and empirical foundation for developing advanced flame-retardant polymeric composites. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： Free radicals  

摘要： The crystalline red phosphorus nanoribbons (cRP NRs) are a new type of material with banded structure, which gives the crystalline red phosphorus nanoribbons unique physical and chemical properties, and makes it have a wide application prospect in the field of photocatalysis. However, the application of cRP NRs in photocatalysis is affected by the problems such as the fast recombination of photogenerated electron holes and the single type of free radicals. In order to improve the photocatalytic degradation efficiency of cRP NRs, the iron-based MOF material MIL-101-NH2 has the advantages of high specific surface area and porosity, and the material was modified by constructing heterojunction. In this paper, we have successfully synthesized cRP NRs with MIL-101-NH2 organic framework materials by solvothermal method. Subsequently, the composite was characterized by SEM and TEM, and the successful composite of cRP NRs and MIL-101-NH2 was confirmed by element distribution scanning and XRD characteristic peaks. In the comparative experiment of photocatalytic degradation of tetracycline, cRP NRs/MIL-101-NH2 showed excellent degradation efficiency, degrading about 80% after 90 min of light. Then, XPS spectral analysis, band gap measurement, Mott-Schottky curve determination and free radical trapping experiments were carried out, and it was confirmed that cRP NRs/MIL-101-NH2 formed Z-scheme heterojunction. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： Shearing  

摘要： In order to study the performance evolution of carbon fiber reinforced epoxy composites under moisture absorption coupling four-point bending load, a four-point bending loading fixture was self-designed to provide the load condition, and 5 times concentration of seawater simulating moisture environment was coupled to simulate the service condition. The damage initiation and propagation process of composite under mechanical loading were monitored in situ by self-designed crack observation system. The effects of different pretreatment conditions on mechanical properties and damage modes were compared and analyzed. The loading area and equal bending moment area of composite under four-point bending pretreatment conditions were evaluated by four-point bending, three-point bending and short beam shearing test, respectively. The results show that the four-point bending property is decreased after pretreatment, the composite is damaged at one end of the loading at first, and then the load continues to decline for several times until the final failure occurs. There is no obvious change in the short beam shearing performance of the equal bending moment section. The three-point bending mechanical test results show that the pretreatment has no significant stress concentration effect on the equal bending moment area. Thus, the pretreatment conditions had a significant effect on the loading area but insignificant on the equal bending moment area. Multiple fracture propagation was observed on the loading area during the failure process, accompanied by interlayer crack propagation. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： 市政工程   给排水管道   改性增强复合材料  

摘要： 给排水管道的质量性能,直接关系市政工程建设发展的效果.结合新时期市政工程建设发展的背景,以市政给排水管道为主要研究对象,从给排水管道应用材料的角度,分析制备改性增强复合材料的方式,探究提升给排水管道材料性能质量的有效思路,旨在为提高市政给排水管道建设水平提供参考.

关键词： SiC   /SiC复合材料   预浸料熔渗   发动机   应用研究  

摘要： 美国通用电气航空公司（简称GE公司）自20世纪80年代开始预浸料-熔渗工艺SiC_f/SiC复合材料的研发，组织数百名科学家和工程师，花费30年、投入近15亿美金，实现了该材料在发动机领域的成功应用与商业化。其整个研发经历可分为工艺研究阶段（1980～2000年）、大规模验证阶段（2000～2015年）、产业化阶段（2015年至今）。工艺研究阶段的主要研发活动包括材料工艺概念提出、概念验证、实验室验证、基础数据积累等。大规模验证阶段的研发活动围绕各种发动机热端构件的试制与技术验证展开，开展了多种热端构件的设计、制造、考核、验证、优化迭代工作。产业化阶段投入了大量资金策划、建立了一个紧密连接的数字化供应链，并持续扩大其在商用发动机上的应用范围。本文详细讨论了SiC_f/SiC复合材料预浸料-熔渗工艺螺旋式的研发历程，以几个热端构件为例介绍了GE公司开展研发的工作思路，尤其详细讨论了F7A发动机涡轮外环长达10年的设计演变过程以及优化迭代背后的原因。随后讨论了GE公司为保持技术先进性的产业化布局和数字化方面的发展规划。最后，基于对GE公司研发过程经验教训的总结，给出了一个国内技术发展的路线图，希望对国内本领域相关技术的发展提供一些有用的参考与借鉴。

关键词： 铝合金钻杆   短碳纤维   SiC   复合材料   高温性能   抗拉强度   深层超深层油气资源  

摘要： 我国浅层和中浅层油气资源总量随着不断开采而逐渐减少，加大深层和超深层油气资源的勘探与开发对于保障国家能源安全具有重要意义。在深层超深层的高温地层进行钻井作业已经成为无法回避的工程难题，研发轻质高强且耐高温的钻杆材料迫在眉睫。本文采用真空热压烧结、热挤压和热处理工艺制备了SiC颗粒以及SiC颗粒和短碳纤维共混2A12铝合金钻杆材料，并对不同SiC体积分数的复合材料在不同温度的性能进行了研究。结果表明，25℃下体积分数为3%的SiC/2A12铝合金复合材料的力学性能最好，抗拉强度较2A12提高10.8%;180℃和220℃下体积分数为5%的SiC/2A12铝合金/碳纤维复合材料的力学性能最好，抗拉强度较基体分别提高17.9%和19.2%。SiC和碳纤维的混合加入可使2A12铝合金的工作温度提高40℃。SiC的强化方式主要是Orowan强化，碳纤维的强化方式主要是载荷传递。