Materials
·
2024
·Vol. 17
·期 15
·3812
·
IF 3.1
Shaohong Liu,Hairui Liu,Limin Zhou,Hao Cui,Manmen Liu,Li Chen,Ming Wen,Haigang Dong,Feng Liu,Wei Wang,Song Li
A novel AgCuTi brazing foil with a unique microstructure was developed, which could achieve strong vacuum brazing of Ti6Al4V (TC4) and sapphire. The brazing foil was composed of Ag solid solution (Ag(s,s)), Cu solid solution (Cu(s,s)), and layered Ti-rich phases, and had a low liquidus temperature of 790 °C and a narrow melting range of 16 °C, facilitating the defect-free joining of TC4 and sapphire. The sapphire/TC4 joint fabricated by using this novel AgCuTi brazing foil exhibited an outstanding average shear strength of up to 132.2 MPa, which was the highest value ever reported. The sapphire/TC4 joint had a characteristic structure, featuring a brazing seam reinforced by TiCu particles and a thin Ti3(Cu,Al)3O reaction layer of about 1.3 μm. The fracture mechanism of the sapphire/TC4 joint was revealed. The crack originated at the brazing seam with TiCu particles, then propagated through the Ti3(Cu,Al)3O reaction layer, detached the reaction layer from the sapphire, and finally penetrated into the sapphire. This study offers valuable insights into the design of active brazing alloys and reliable metal–ceramic bonding.
研究领域:
材料科学
·
焊接工程
✓ 已验证
DOI
PubMed
高影响因子
POLYMER
·
2022
·
IF 4.432
Lijie Lin,Yingzhu Wang,Zhiyong Lin,Weiang Luo,Hong Zhang,Guorong Chen,Hesheng Cao,Conghui Yuan,Yiting Xu,Birong Zeng,Lizong Dai
Understanding the reinforcement and fracture mechanism of polymer matrix nanocomposites is crucial for the design of high-performance composite materials. By taking boron nitride@boronate polymer core-shell nanoparticles modified epoxy resin nanocomposites (EPNCs) as an example, a reinforcement and fracture mechanism analysis model of nanocomposites was established through the combination of experiments and simulations. Instead of the traditional programming method by using the external language, a new modeling method was introduced with the help of Digimat. The results indicated that the interface force between (within) EP matrix and nanoparticles , the shell thickness and nanoparticle content play important roles in the reinforcement and fracture of EPNCs. The bending strength increases with the raising of particle content, but decreases with the increasing of shell thickness. The simulated results were consistent with the experiments. The interface force evolves according to the order of interfaces within particles and their shell > matrix-shell > matrix interior. A proper interfacial force can make interfacial debonding and matrix failure occur at the same time, thus improving both the strength and toughness of nanocomposites. This model construction will provide theoretical guidance for nanocomposites design and the clarification of reinforcement mechanism.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Manufacturing Processes
·
2021
·
IF 5.01
Mengyuan Zhou,Xiaowei Zhou,Liang Si,Peng Chen,Maoyuan Li,Yun Zhang,Huamin Zhou
Fused Filament Fabrication (FFF) is one of the most widely used material extrusion additive manufacturing techniques . Its application is limited by the poor mechanical properties because of the weak bonding interface between strands. Although numerous experimental studies have investigated the effects of process parameters on mechanical performances, the bonding fracture mechanism and the quantitative relationship between process parameters and the bonding strength are not well understood. Here, we report a novel theoretical model considering coupled effects of the bonding interface evolution and molecular diffusion for predicting the bonding strength, which provides a comprehensive insight into the FFF bonding process. The model establishes an accurate relationship between process parameters and the bonding strength parallel/perpendicular to the deposition direction. Predictions agree well with experimental results and the average root mean square error (RMS) is ~5.52%. The fracture mechanism confirms the variation of the bonding interface and molecular diffusion assumed in the model. The bonding interface evolution and molecular diffusion are proved to play an important role in the bonding strength.
研究领域:
材料科学
·
力学
✓ 已验证
DOI
高影响因子
2D Materials
·
2019
·Vol. 7
·期 1
·015025
·
IF 7.343
Xiao You,Jinshan Yang,Mengmeng Wang,Jianbao Hu,Yusheng Ding,Xiangyu Zhang,Shaoming Dong
Free-standing stretchable fibers with highly flexibility and sensitivity are the key components of the smart wearable electronic devices. In this work, one-dimensional graphene-based fibers with aligned morphology are fabricated by direct ink extrusion, in which graphene and poly(dimethyl siloxane) (PDMS) can be integrated into a conductive network. The graphene-based fibers can respond to multiple deformations such as bending, twisting, compressing, and stretching. The various response amplitude with a reversible electrical resistance change can be obtained from multiple strain cycles, which exhibits high sensitivity and broad range in strain sensing. The ultra-sensitive electromechanical property with a gauge factor of 65 under 6% strain is attributed to the interwoven graphene network and could be cycled 600 times of continuous stretching−releasing process with less than 6.2% attenuation in the response signal. The intrinsic dynamic fracture procedure and mechanism of graphene-based fibers are investigated as a result of the gradual growth of locally generated cracks. The controllable fabrication of graphene-based fibers with high sensitivity shows great potential applications in stretchable wearable sensors for real-time monitoring and distinguishing of human motion and gestures.
研究领域:
材料科学
·
电子工程
·
纳米技术
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 40
·31365-31374
·
IF 3.84
Ruiwei Guo,Pengbo Mei,Qing Zhong,Yuan Yao,Qian Su,Jianhua Zhang
The effective preparation of photoresponsive polymers with precisely controlled location and number of photolabile units in the main chain is essential for their applications. In this study, a series of photocleavable well-defined triblock copolymers with the photocleavable middle block of poly(phenyl vinyl ketone) (PPVK) were readily synthesized by RAFT polymerization. The chain structure and chemical composition of copolymers were characterized by 1HNMR, FTIR and GPC. The well-controlled molecular weights and low polydispersity (<1.30) demonstrated the excellent controllability and living characteristics of the RAFT process for the polymerization of PVK. Then the photocleavage mechanism and kinetics of PPVK-functionalized copolymers were systematically investigated by tracking, fractionating and quantifying the photolysis products using gradient polymer elution chromatography (GPEC). The results not only confirmed the rapid photocleavability of PPVK-based polymers, but also firstly provided direct evidence for the proposed Norrish type reaction mechanism of the chain scission of PPVK. Moreover, the investigation of the effect of the PPVK chain on the photolysis kinetics demonstrated that the photodegradation rate of PPVK-based polymers can be controlled by adjusting the PPVK chain length in block copolymers. As a preliminary application study, the self-assembled micelles of the obtained PPVK-based amphiphilic polymers under light irradiation were found to undergo photo-triggered rapid disassembly and exhibited photo-controllable emulsifiability. In sum, the incorporation of the highly photolabile PPVK into block copolymers by RAFT polymerization provides a promising strategy for the construction of complex polymeric architectures or nanostructures with controllable photocleavability.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2019
·
IF 3.372
Chang Li,Jie Lin,Liming Shen,Ningzhong Bao
Ultrasonic exfoliation is the most widely used delamination technique for producing graphene oxide. In this work, the exfoliation of graphite oxide suspension is conveniently monitored via real-time measurement of viscosity and then quantitatively described by using the relative single-layer fraction ( α ) for the first time, by which the full exfoliation is achieved with a time scale of minutes. Lateral size evolution is demonstrated using lognormal distribution based on statistical analysis. With the quantization of relative single-layer fraction and lateral size distribution, a prototype database has been built to efficiently integrate experimental data tested under different process conditions (suspension concentration, ultrasonic frequency, and ultrasonic power density), which can be used as reference guides for process optimization and product control. The selection and breakage functions ( S i and B ij ) of ultrasound-assisted exfoliation are calculated and the breakage mechanisms of graphite oxide are found attributed mainly to sheet fracture.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Sciences
·
2023
·
IF 6.9
Yunjin Zhong,Lebing Zhuo,Wangyang Lu
Microplastic pollution has become one of the most concerned focuses in the world. Among many treatment methods, photocatalysis is considered to be one of the most environmentally friendly methods. In this work, the photodegradation behavior of polyamide microplastics is studied by using polyamide 6 PA6) as model microplastics and FeCl 3 as catalyst. It is hoped that the PA6 fiber can be effectively degraded by utilizing the strong oxidizing active species that can be produced after FeCl 3 is irradiated in water. The results shows that PA6 fiber can be almost completely degraded after 10 days of irradiation in FeCl 3 aqueous solution, indicating that it is promising to use this new method to solve the problem of PA6 type microplastics. In addition, the chain scission mechanism and degradation process of PA6 are analyzed in detail by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS), which provides a new insight for the study of polymer degradation mechanism.
研究领域:
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENERGY & FUELS
·
2023
·
IF 5.3
Xiaojun Dai,Yan Cheng,Tingting Liu,Lingjuan Mao,Qiang Wei,Yasong Zhou
SAPO-11 molecular sieves with different crystal sizes and particle sizes, especially nanosized small-crystal SAPO-11 molecular sieves, were successfully synthesized, and the corresponding NiWS-supported catalysts were prepared for the hydroisomerization of n-hexadecane. XRD, SEM, N2 adsorption–desorption, Py-IR, and HRTEM were used to analyze the effects of crystal size and particle size of the supports on their physicochemical properties, active phase properties, and catalytic performance of the catalysts. Through reaction evaluation and analysis of isomeric products, the effects of the size change of the support on the hydroisomerization performance of the catalyst and the hydroisomerization depth of n-hexadecane were determined. Through comprehensive analysis of the cracking products, it was determined that secondary cracking occurred when the conversion of n-hexadecane on the NiW/SAPO-11-S catalyst reached about 42.7%, and the secondary isomerization occurred when the conversion of n-hexadecane reached about 80%. The hydroisomerization reaction network of n-hexadecane over the NiWS/SAPO-11 catalyst was studied emphatically, and it was found for the first time that the secondary cracking of n-hexadecane during hydroisomerization followed the C3-β-scission mechanism.
研究领域:
化学工程
·
催化
·
材料科学
✓ 已验证
DOI
高影响因子
Science Advances
·
2025
·Vol. 11
·期 29
·
IF 12.5
Ruihao Zhou,Muqing Cao,Yizheng Tan,Mark Neisser,Huaping Xu
Extreme ultraviolet (EUV) lithography has become the essence of advanced semiconductor manufacturing processes. While enabling smaller feature sizes, EUV lithography imposes increasingly stringent requirements on the comprehensive performance and stochastic defect suppression of photoresist. The widely recognized strategy to minimize these defects is a material that integrates high EUV absorption and energy utilization into a homogeneous system based on molecular building blocks—the ideal formulation for EUV photoresist. However, achieving these integrated characteristics within a single molecule has remained an unresolved challenge. Here, we address all these requirements by polytelluoxane using an organic telluride monomer polymerized via Te─O bonds. This polymeric photoresist, operating through a main chain scission mechanism, demonstrates high-performance positive-tone lithography. Attributed to this ideal formulation, our photoresist achieves a comprehensive 18-nm line width at a dose of 13.1 mJ/cm 2 with a line edge roughness of 1.97 nm. We believe that this strategy establishes a framework for the design of next-generation EUV photoresists.
研究领域:
半导体制造
·
材料科学
·
纳米技术
·
光刻技术
·
高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）