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Local amorphization in boron carbide at finite temperature: Strategies toward improved ductility

Physical Review B 2021年第13期104卷 134105-134105页

作者： Jun Li Qi An Lisheng Liu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Department of Chemical and Materials Engineering University of Nevada-Reno Reno Nevada 89557 USA

Boron carbide (B4C) is superhard, but its engineering applications are limited by the abnormal brittle failure arising from amorphous shear band formation. Mitigating the local amorphization is essential to improve the ductility of B4C. Here, we carried out ab initio molecular dynamics (AIMD) simulations to examine the response of B4C to shear along two plausible slip systems (001)/[100] and (111)/[112¯] at finite temperature. We found that the icosahedra of B4C gradually deconstruct at finite temperature, resulting in local amorphization, thereby giving rise to a lower stress barrier than that of density functional theory simulations at zero temperature. The deconstruction of the icosahedral clusters arises from the interaction with the neighboring chains. The failure mechanism at the finite temperature suggested that the local amorphization can be suppressed by altering the structure of the 12-atom icosahedron and the 3-atom chain of B4C. To demonstrate this, we replaced the B11CP icosahedron in B4C with B12 icosahedron to form boron-rich boron carbide (B13C2) and then performed the same shear deformations. We found that local amorphization significantly decreases, which results from the modified icosahedral interaction. We also altered the 3-atom C-B-C chain to the 2-atom P-P chain and found that the accumulated shear stress can be released through icosahedral slipping, which is achieved by breaking the chains. The icosahedral slipping then prevents the destruction of icosahedra under shear deformations, expected to improve the ductility. Our results demonstrate two design strategies toward improved ductility of B4C: (1) boron enrichment can alleviate amorphous shear band formation in boron carbide, and (2) altering the 3-atom chain to a 2-atom chain and meanwhile decreasing the strength of the chain to make it less stable than the icosahedron cage may lead to an icosahedral-slipping-dominated mechanism, thereby avoiding icosahedral fracture.

关键词： Material failure Mechanical & acoustical properties Phase transitions Shear deformation

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Control of the proximity of bifunctional [email protected] 2 O 3 catalysts for efficient methanol conversion into hydrocarbons

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Catalysis Today 2022年 405-406卷 82-91页

作者： Jia-Min Lyu Shen Yu Zhao Peng Jian Zhou Zhan Liu Xiao-Yun Li Yu-Li Li-Hua Chen Bao-Lian Su State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 Hubei China State Key Laboratory of Green Chemical Engineering and Industrial Catalysis Shanghai Research Institute of Petrochemical Technology SINOPEC Shanghai 201208 China State Key Laboratory of Silicate Materials for Architecture Wuhan University of Technology Wuhan 430070 Hubei China Laboratory of Inorganic Materials Chemistry (CMI) University of Namur Namur B-5000 Namur Belgium

Bifunctional catalysts are widely applied for many important reactions as the synergetic effect of two types of active sites remarkably improves catalysis performance. However, their bifunctionality has not been fully exploited since the proximity of bifunctional catalysts is hard to control. Herein, we demonstrate a bifunctional [email protected] 2 O 3 catalyst with a core-shell structure and a nano-scale proximity by in-situ growth of γ-Al 2 O 3 nanosheets on the surface of ZSM-5 crystals for methanol conversion. The nano-scale proximity endows the catalyst with higher reaction activity and C 2 –C 3 olefins yield (53 %) in comparison to the catalysts with micro-scale proximity (20 %) and millimeter-scale proximity (27 %), which can be attributed to the fluent transport of the reaction intermediates between two types of active sites. This strategy for constructing bifunctional catalysts with nano-scale proximity is conducive to understanding the relationship between proximity and catalytic performance in methanol conversion.

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Hydrophilic bi-functional B-doped g-C_(3)N_(4) hierarchical architecture for excellent photocatalytic H_(2)O_(2) production and photoelectrochemical water splitting

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Journal of Energy Chemistry 2022年第7期31卷 236-247,I0007页

作者： Yang Ding Soumyajit Maitra Chunhua Wang Runtian Zheng Meiyu Zhang Tarek Barakat Subhasis Roy Jing Liu Yu Li Tawfique Hasan Bao-Lian Su Laboratory of Inorganic Materials Chemistry(CMI) University of Namur61 rue de BruxellesB-5000 NamurBelgium Namur Institute of Structured Matter(NISM) University of Namur61 rue de BruxellesB-5000 NamurBelgium Department of Chemical Engineering University of Calcutta92 APC RoadWest BengalKolkata 700009India Department of Chemistry KU LeuvenCelestijnenlaan 200FB-3001 LeuvenBelgium State Key Laboratory of Applied Organic Chemistry Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu ProvinceCollege of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000GansuChina State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070HubeiChina Cambridge Graphene Centre University of CambridgeCambridgeCB30DSUK Clare Hall University of CambridgeUnited KingdomCB21EWUK

Graphitic carbon nitride(g-C_(3)N_(4))has attracted great interest in photocatalysis and ***,their poor hydrophilicity poses a great challenge for their applications in aqueous ***,we demonstrate synthesis of a hydrophilic bi-functional hierarchical architecture by the assembly of B-doped g-C_(3)N_(4)*** hierarchical B-doped g-C_(3)N_(4)material enables full utilization of their highly enhanced visible light absorption and photogenerated carrier separation in aqueous medium,leading to an excellent photocatalytic H_(2)O_(2)production rate of 4240.3μM g^(-1)h^(-1),2.84,2.64 and 2.13 times higher than that of the bulk g-C_(3)N_(4),g-C_(3)N_(4)nanoplatelets and bulk B doped g-C_(3)N_(4),*** based on these hierarchical architectures can generate an unprecedented photocurrent density of 1.72 m A cm^(-2)at 1.23 V under AM 1.5 G illumination for photoelectrochemical water *** work makes a fundamental improvement towards large-scale exploitation of highly active,hydrophilic and stable metal-free g-C_(3)N_(4)photocatalysts for various practical applications.

关键词： Boron doping Hydrophilicity Hierarchically assembled architectures Photocatalytic H_(2)O_(2)production Photoelectrocatalytic water splitting

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Elastic properties of Cu-6wt%Ag alloy wires for pulsed magnets investigated by ultrasonic techniques

arXiv

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arXiv 2024年

作者： Li, Ziyu Gu, Tianyi Wei, Wenqi Yuan, Yang Wang, Zhuo Luo, Kangjian Pan, Yupeng Xie, Jianfeng Zhang, Shaozhe Peng, Tao Liu, Lin Chen, Qi Han, Xiaotao Luo, Yongkang Li, Liang Wuhan National High Magnetic Field Center Huazhong University of Science and Technology Wuhan430074 China School of Physics Huazhong University of Science and Technology Wuhan430074 China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan430074 China School of Materials Science and Engineering State Key Lab for Materials Processing and Die & Mold Technology Huazhong University of Science and Technology Wuhan430074 China

Conductor materials with good mechanical performance as well as high electrical- and thermal-conductivities are particularly important to break through the current bottle-neck limit (∼ 100 T) of pulsed magnets. Here we perform systematic studies on the elastic properties of the Cu-6wt%Ag alloy wires, a promising candidate material for the new-generation pulsed magnets, by employing two independent ultrasonic techniques - resonant ultrasound spectroscopy (RUS) and ultrasound pulse-echo experiments. Our RUS measurements manifest that the elastic properties of the Cu-6wt%Ag alloy wires can be improved by an electroplastic drawing procedure as compared with the conventional cold drawing. We also take this chance to test the availability of our newly-built ultrasound pulse-echo facility at Wuhan National High Magnetic Field Center (WHMFC, China), and the results suggest that the elastic performance of the electroplastically-drawn Cu-6wt%Ag alloy wire remains excellent without anomalous softening under extreme conditions, e.g., ultra-high magnetic field up to 50 T, nitrogen / helium cryogenic liquids. © 2024, CC BY.

关键词： Bottles

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Perfecting and extending the near-infrared imaging window

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Light(Science & Applications) 2021年第10期10卷 1949-1966页

作者： Zhe Feng Tao Tang Tianxiang Wu Xiaoming Yu Yuhuang Zhang Meng Wang Junyan Zheng Yanyun Ying Siyi Chen Jing Zhou Xiaoxiao Fan Dan Zhang Shengliang Li Mingxi Zhang Jun Qian State Key Laboratory of Modern Optical Instrumentations Centre for Optical and Electromagnetic ResearchCollege of Optical Science and EngineeringInternational Research Center for Advanced PhotonicsZhejiang University310058 HangzhouChina Intelligent Optics&Photonics Research Center Jiaxing Institute of Zhejiang University314000 JiaxingZhejiang ProvinceChina State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology430070 WuhanChina Key Laboratory of Reproductive Genetics(Ministry of Education) Department of Reproductive EndocrinologyWomen’s HospitalZhejiang University School of Medicine310006 HangzhouChina College of Pharmaceutical Sciences Soochow University215123 SuzhouChina

In vivo fluorescence imaging in the second near-infrared window(NIR-II)has been considered as a promising technique for visualizing ***,the definition of the NIR-II region and the mechanism accounting for the excellent performance still need to be ***,we simulate the photon propagation in the NIR region(to 2340 nm),confirm the positive contribution of moderate light absorption by water in intravital imaging and perfect the NIR-II window as 900–1880 nm,where 1400–1500 and 1700–1880 nm are defined as NIR-IIx and NIR-IIc regions,***,2080–2340 nm is newly proposed as the third near-infrared(NIR-III)window,which is believed to provide the best imaging *** wide-field fluorescence microscopy in the brain is performed around the NIRIIx region,with excellent optical sectioning strength and the largest imaging depth of intravital NIR-II fluorescence microscopy to *** also propose 1400 nm long-pass detection in off-peak NIR-II imaging whose performance exceeds that of NIR-IIb imaging,using bright fluorophores with short emission wavelength.

关键词： perfect Perfect fir

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Hybrid Deposition of Altin/Wn Multilayer Films with Low Compressive Stress at Low Temperature

SSRN

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SSRN 2024年

作者： Lin, Liangliang Zhang, Song Wu, Zhengtao Lin, Yisong Zheng, Aiqin Liu, Chao Tu, Rong Wang, Qiming State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology 122 Luoshi Road Wuhan430070 China School of Electromechanical Engineering Guangdong University of Technology Guangzhou510006 China Xiamen Golden Egret Special Alloy Co. Ltd Xiamen361006 China Xiamen Tungsten Co. Ltd Xiamen361004 China

AlTiN/WN multilayer films with low compressive stress were deposited by arc evaporation and DC magnetron sputtering at a low temperature. The phase structure, morphologies, mechanical properties, wear behavior, and cutting performance of the AlTiN/WN multilayer films were evaluated. The results show that all the as-prepared AlTiN/WN multilayer films have fcc structure and exhibit (111) preferred orientation. The lowest value -1.7 GPa for compressive stress was obtained under low-temperature deposition. The film hardness increases as the temperature increases. Increasing the WN layer thickness reduces the adhesion strength of the film. Compared with room temperature, The friction coefficients of the films against Al2O3 and steel reduce at high temperatures. This was attributed to lubricative oxides formed on the wear surface at high temperatures. Dry cutting experiments were conducted and the longest service life of the coated tool reaches ~3700 m. The worn flank surface shows that both adhesion and abrasive wear dominate the failure of the coated tools. © 2024, The Authors. All rights reserved.

关键词： Multilayers

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Zn0.1cd0.9s/Nis Heterojunction Photocatalysts for Enhanced H2 Production and Glucose Conversion

SSRN

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SSRN 2023年

作者： Li, Yu Shen, Yuan-Sheng Bai, Fang-Yuan Wei, Ke Wang, Xin-Ling Chen, Jun Jiang, Ze-Yu Liu, Jing Hu, Zhi-Yi Chen, Li-Hua Su, Bao-Lian State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology 122 Luoshi Road Hubei Wuhan430070 China Wuhan University of Technology 122 Luoshi Road Hubei Wuhan430070 China University of Namur 61 rue de Bruxelles Namur5000 Belgium

The well-designed photocatalyst is a reasonable strategy to improve the photocatalytic performance and realize the photocatalytic H2-production and biomass conversion. In this work, the Zn0.1Cd0.9S/ NiS (SNS) composite was successfully prepared by chemical bath deposition of NiS nanoparticles on Zn0.1Cd0.9S (ZCS) nanorods surface. Our results show that the synergistic effect of NiS and ZCS largely improves the absorption and utilization of light, and the separation of photogenerated carriers because the one-dimensional nanorods is conducive to the transmission of photogenerated carriers. The optimized catalyst (SNS20) has the highest H2-production rate (12.77 mmol·g-1·h-1), which is 6.7 times that of pure ZCS nanorods. The glucose conversion increases from 25.7% to 49.9% and lactic acid selectivity reaches 95%. This work provides a reasonable strategy for designing heterojuction photocatalyst to improve the performance for the synergy of photocatalytic H2-production and biomass conversion. © 2023, The Authors. All rights reserved.

关键词： Nanorods

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Regulating electron transfer through imine linkage orientations in two-dimensional covalent organic frameworks for efficient electrochromism

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Chemical Engineering Journal 2025年 516卷

作者： Shi, Wenping Zhou, Jing Xiong, Yuli Chen, Wen State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Materials Science and Engineering Wuhan University of Technology Wuhan430070 China

Two-dimensional covalent organic frameworks (2D-COFs) based on imine linkages have been shown to offer intriguing optical and electrochromic (EC) performance, attracting extensive attention in the field of advanced photo-electrochemistry. However, few studies have explored how the orientation of imine linkages in 2D-COFs regulates electron transfer behavior and subsequently affects EC performance. In this work, we report an isomeric pair (Py-C-TP-COF and Py-N-TP-COF), differing only in the orientations of the imine linkages. Experimental and theoretical results demonstrate that significant differences in the electronic orbital contributions and bandgaps of 2D-COFs with distinct imine linkage orientations. Furthermore, the different orientations of imine linkages play a crucial role in the distribution of the highest occupied and the lowest unoccupied molecular orbital (HOMO and LUMO), thus significantly influencing electron separation and charge transfer. This approach of altering imine linkage orientations allows for the fine control of the charge transport and band structure of the 2D-COFs. As a result, the Py-C-TP-COF film exhibits excellent EC performance with high coloration efficiency (ηCE,1316 cm2·C-1), fast switching time (2.0/0.4 s) and outstanding cycling stability (99.5 % retention of EC cyclic stability after 150 cycles). This study provides new insights for further rational design and optimization of functional COFs as EC materials with atomically regulated charge transfer. © 2025 Elsevier B.V.

关键词： Molecular orbitals

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Study on Constitutive Model and Fracture Criterion of 7075 Aluminum Alloy at High Temperature

SSRN

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SSRN 2023年

作者： Wang, Zijian Zhang, Xiaolei Gui, Jiangtao Geng, Huicheng Xiang, Chongchen Ding, Hanlin School of Iron and Steel Soochow University Suzhou215137 China Yangtze Delta Region Institute of Advanced Materials Suzhou215000 China State Key Lab of Materials Processing and Die and Mould Technology Huazhong University of Science and Technology Wuhan430074 China

Hot stamping has been widely used to solve the problems of spring back and cracking of aluminum alloy after cold forming. However, sheets are prone to failures like wrinkling and cracking during hot forming. Therefore, it is particularly important to establish a correct material model that can accurately reflect the deformation and fracture of the material. In this study, Tensile tests were conducted on the specimens at different temperatures, and Digital Image Correlation (DIC) was employed to obtain the specimen strain. The Yld2000-3d anisotropic yield criterion and the DF2014 fracture criterion were calibrated based on experiments and modeling, which were then used to characterize the anisotropy and fracture behavior of 7075 aluminum alloy, respectively. The specimens were also observed for fracture surface morphology. As the experiments and simulation results revealed, the 7075 aluminum alloy still had a more pronounced anisotropy at high temperatures. Finite element simulation was performed to obtain the parameters of the DF2014 fracture model at different temperatures. The results showed that the DF2014 fracture model could accurately predict the fracture behavior of the aluminum alloy. The specimens exhibited brittle fracture at room temperature, while the behavior changed to typical ductile fracture as the temperature rose. © 2023, The Authors. All rights reserved.

关键词： Anisotropy

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synthesis of Cr_2AlC from Elemental Powders with Modified Pressureless Spark Plasma Sintering

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Journal of Wuhan University of technology(materials Science) 2019年第2期34卷 287-292页

作者：葛梦妮 WANG Xiaofan LI Gaiye LU Chen 张建峰 TU Rong College of Mechanics and Materials Hohai University State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology

We introduced a modified pressureless sintering strategy by SPS with a new T-shape die and tapered punches, which helps the evaporation of melted Al and reduces the sample sticking with the inner wall of the die. Thus, the die breaking risk in the sintering process or the de-molding process is avoided at all. At a low temperature and short holding time, a high purity of Cr_2 AlC was obtained in this SPS process from the optimization of different molar ratios of raw materials. Simultaneously, the high porosity of the as-obtained sample was also a distinguishing feature worth noticing. The reaction mechanism for this process was also discussed in detail. This study presented a new venue for future development of high purity "MAX" materials and others related materials by a modified pressureless sintering strategy.

关键词： pressureless spark plasma sintering Cr2AlC reaction mechanism

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