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Introducingωand O'nanodomains in Ti-6Al-4V:The mechanism of acceleratingα→βtransformation kinetics via electropulsing

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Journal of materials science & Technology 2023年第31期162卷 109-117页

作者： Yachong Zhou Xiaofeng Xu Yang Zhao Xudong Yan Lai Wei Zhicheng Wu Chao Wu Key Laboratory of Automobile Materials Ministry of EducationDepartment of Materials Science and EngineeringJilin UniversityChangchun 130000China Weihai Institute for Bionics-Jilin University Weihai 264200China Key Laboratory of Bionic Engineering Ministry of EducationJilin UniversityChangchun 130000China

Conventional kinetics theory for diffusion-controlled phase transformation shows that the reverse transition should lag behind the temperature rise through rapid heating,i.e.,overheating is *** this work,we found that theβ-transus temperature decreased by∼50℃ during studying theα→βtransformation in Ti-6Al-4V alloy via electropulsing treatment(EPT).The calculation suggests that the acceleration of transformation kinetics cannot be fully explained by Joule heat and athermal effects of the electromigration effect and electron wind *** microstructural evolution during EPT was systematically investigated utilizing scanning electron microscope(SEM),electron backscattered diffraction(EBSD),X-ray diffraction(XRD),transmission Kikuchi diffraction(TKD),and transmission electron micro-scope(TEM).Microscopic analysis shows that the nano-sizedωand O'phases formed in theβphase,which causes large numbers of lattice distortion *** defects are conducive to accelerating the bulk diffusion of alloying elements inβ.Moreover,the nanodomains limited the growth of martensite,therefore nanocrystalline martensite formed after *** findings develop the understanding of the destructive effect of current on metallic crystal,which will help to guide microstructural regulation in titanium and other alloys.

关键词： Titanium alloy Phase transformation kinetics Electropulsing Nanodomain Diffusion

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Tertiary orientation structures enhance the piezoelectricity of MXene/PVDF nanocomposite

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Nano Research 2024年第6期17卷 5629-5635页

作者： Yong Ao Tao Yang Guo Tian Shenglong Wang Tianpei Xu Lin Deng Jieling Zhang Lihua Tang Weili Deng Long Jin Weiqing Yang Key Laboratory of Advanced Technologies of Materials(Ministry of Education) School of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Department of Mechanical Engineering The University of AucklandAuckland 1010New Zealand Research Institute of Frontier Science Southwest Jiaotong UniversityChengdu 610031China

With the increasing demand for flexible piezoelectric sensor components,research on polyvinylidene fluoride(PVDF)based piezoelectric polymers is mounting ***,the low dipole polarization and disordered polarization direction presented in PVDF hinder further improvement of piezoelectric ***,we constructed an oriented tertiary structure,consisting of molecular chains,crystalline region,and MXene sheets,in MXene/PVDF nanocomposite via a temperature-pressure dual-field regulation *** highly oriented PVDF molecular chains form approximately 90%of theβ*** addition,the crystalline region structure with long-range orientation achieves out of plane polarization *** parallel orientation arrangement of MXene effectively enhances the piezoelectric performances of the nanocomposite,and the current output of the device increases by nearly 23 *** high output device is used to monitor exercise action,exploring the potential applications in wearable electronics.

关键词： flexible sensor piezoelectric MXene/polyvinylidene fluoride(PVDF)nanocomposite orientation structures

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The New Methods for Characterization of Molecular Weight of Supramolecular Polymers

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Chinese Journal of Polymer science 2024年第10期42卷 1403-1413,I0006页

作者： Hui Liu Rui Hu Zi-Qing Hu Xiao-Fan Ji Key Laboratory of Materials Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Materials Chemistry and Service FailureHubei Engineering Research Center for Biomaterials and Medical Protective MaterialsSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074China

Supramolecular polymers,as a type of dynamic polymers,are subordinate to the interdisciplinary field of polymer chemistry and supramolecular chemistry,whose development has greatly promoted the prosperity of new ***,molecular weight is one of the most important parameters of supramolecular polymers,which affects the physical/chemical properties and processing applications of *** new methods for characterizing the molecular weight of supramolecular polymers is crucial for advancing the development of supramolecular *** this review,we elaborate and summarize three strategies for characterizing the molecular weight of supramolecular polymers that recently reported by our research group according to the characteristics of supramolecular polymers,including(1)the molecular weight distinction corresponding to variable fluorescence colors,(2)matching different molecular weights with different fluorescence lifetime,(3)transforming supramolecular polymers into mechanically interlocked polymers or covalent ***,we also discuss the limitations of current methods for characterizing supramolecular *** hope that this review can promote the development of supramolecular polymers and significantly inspire to exploit new methods to characterizing molecular weight of supramolecular polymers.

关键词： Supramolecular polymers Molecular weight Self-assembly Mechanically interlocked polymers Dynamic polymers

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Study on water absorption of cement-based materials containing water repellent by using low-field nuclear magnetic resonance 4

Study on water absorption of cement-based materials containi...

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2024 4th International Conference on Industrial Manufacturing and Structural materials, IMSM 2024

作者： Raja, Al Jarmouzi Sun, Zhenping Key Laboratory of Advanced Civil Engineering Materials Ministry of Education School of Materials Science and Engineering Tongji University Shanghai China

Water absorption and aggressive ions play a fundamental role in estimating the chemical and physical degradation of cement-based materials' structure, leading to a decline in durability and lifespan. Water absorption by cement-based structures is accompanied by a subsequent reconfiguration of nano-scale porosity, resulting in water entrapment. Therefore, limiting water absorption by using water-repellent admixtures as an integral hydrophobic modifier during the mixing process of fresh cement paste is needed. Additionally, the low-field nuclear magnetic resonance (LF-NMR) technique was employed to characterize the water absorption of cement paste containing water-repellent admixtures and integral hydrophobicity. Cement pastes with 0-3% dosages of Isobutyltriethoxysilane (IS) were prepared. The effect of IS on transverse relaxation time (T2), pore size distribution variations, pore structure development, and total peak area by LF-NMR of cement paste during the water absorption process from 0 to 72 hours were measured. The results indicate that the intensity signal of T2 distribution and the amount of water in capillary pores of control cement paste (CP) sharply increased during the absorption process. Furthermore, the CP exhibited the highest absorption rate during the immersion process. The cement paste incorporated with IS signals the intensity of T2 distribution and the water in capillary pores is significantly reduced. The IS specimens showed the lowest absorption rate and the amount of water in capillary pores was reduced. The addition of IS admixtures exhibited high efficiency in resisting capillary water absorption, which could have numerous applications in protecting concrete structures in coastal areas, including coastal architecture, sea bridges, flood control dams, and ports. © Published under licence by IOP Publishing Ltd.

关键词： Flood control

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advanced Microfluidic Photonic Sensor Based on Precision Integrated Fiber Probe

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Journal of Lightwave Technology 2025年第12期43卷 5996-6003页

作者： Su, Chunbo Yang, Wenjie You, Yuqi Ma, Yiwei Liu, Yongjun Geng, Tao Harbin Engineering University Key Lab of In-Fiber Integrated Optics Ministry Education of China Harbin150001 China Harbin Engineering University Key Laboratory of Superlight Materials and Surface Technology Ministry of Education College of Materials Science and Chemical Engineering Harbin150001 China

In microfluidic systems, slight changes can lead to vital performance differences, accurate microfluidic monitoring is essential to ensure that the microfluidic device is working properly and achieving its intended function. A reflective long-period fiber grating (LPFG) probe for microflow monitoring is designed and demonstrated, by periodically embedding a multi-mode fiber (MMF) into a single-mode fiber (SMF) and integrating a metal mirror at the end. This design not only solves the inherent problem that LPFG can only receive transmitted light, but also reduces the overall structure by half, providing an attractive solution for the design of high precision microflow monitoring probes. The experimental results show that the liquid level and temperature resolution of LPFG probe in microfluidic monitoring are 5.72 μm and 0.29 °C. The maximum error of temperature and volume (liquid level) accuracy detection in the randomized experiment is 0.4 μL and 0.06 °C, which has an admirable precision and accuracy. It is also significant that miniaturized photonic sensors are more conducive to integration in chips. This innovative work provides an original idea for the function upgrade and integration of LPFG components, which has an attractive application prospect in the integration of photonics technology and microflow system. © 1983-2012 IEEE.

关键词： Probes

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Thin-walled and large-sized magnesium alloy die castings for passenger car cockpit:Application,materials,and manufacture

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China Foundry 2024年第5期21卷 525-545页

作者： Lei Zhan Yu-meng Sun Yang Song Chun-hua Kong Kai Ma Bai-xin Dong Hong-yu Yang Shi-li Shu Feng Qiu School of Automotive Engineering Jilin Communication PolytechnicChangchun 130012China Key Laboratory of Automobile Materials of Ministry of Education School of Materials Science and EngineeringNanling CampusJilin UniversityChangchun 130025China

In order to effectively reduce energy consumption and increase range mile,new energy vehicles represented by Tesla have greatly aroused the application of integrated magnesium(Mg)alloy die casting technology in ***,the application of Mg alloys in automobiles,especially in automotive cockpit components,is quite extensive,while it has almost disappeared for a period of time due to its relatively high cost,causing a certain degree of information loss in the application technology of Mg alloy parts in *** rapid development of automotive technology has led to a higher requirement for the automotive components compared with those traditional ***,whatever the components themselves,or the Mg alloy materials and die casting process have to face an increasing challenge,needing to be *** addition,owing to its high integration characteristics,the application of Mg alloy die casting technology in large-sized and thin-walled automotive parts has inherent advantages and needs to be expanded ***,it necessitates exploring advance Mg alloys and new product structures and optimizing die casting *** article summarizes and analyzes the development status of thin-walled and large-sized die casting Mg alloy parts in passenger car cockpit and corresponding material selection methods,die casting processes as well as mold design ***,this work will aid researchers in establishing a comprehensive understanding of the manufacture of thin-walled and large-sized die casting Mg alloy parts in automobile *** will also assist them in developing new Mg alloys with improved comprehensive performance and new processes to meet the high requirements for die casting automotive components.

关键词： Mg alloys thin wall large size automotive part die casting

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Photo-induced tunable luminescence from an aggregated amphiphilic ethylene-pyrene derivative in aqueous media

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Chinese Chemical Letters 2024年第6期35卷 303-306页

作者： Junying Zhang Ruochen Li Haihua Wang Wenbing Kang Xing-Dong Xu National Engineering Research Center for Colloidal Materials Key Laboratory of Special Functional Aggregated Materials of Ministry of EducationShandong Key Laboratory of Advanced Silicone Materials and TechnologySchool of Chemistry and Chemical EngineeringShandong UniversityJi’nan 250100China

An amphiphilic derivative with a large Stokes shift by introducing flexible hydrophilic long chains into a rigid ethylene-pyrene compound have been successfully *** alkylated compound exhibited a notable change in charge distribution,facilitating cation-π *** the process of amphiphilic self-assembly,the formation of highly ordered aggregates enabled effective photo-dimerization under 449 nm LED ***,this photo-responsive technology not only exhibited advanced multi-color emission effects,including white light emission but also exhibited environmentally friendly behavior in the aqueous phase.

关键词： Supramolecular chemistry Amphiphilic assembly Stimuli-responsive materials Tunable luminescence Pyrene derivative

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Synergistic strengthening mechanism of gradient structure AZ31 magnesium alloy plate in hard plate rolling

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Progress in Natural science:materials International 2023年第5期33卷 652-659页

作者： Wen Tao Niu Feng Li Jia Yang Zhang Chao Li Lu Sun School of Materials Science and Chemical Engineering Harbin University of Science and Technology Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of Education Harbin University of Science and Technology Heilongjiang Provincial Key Laboratory of Light Metal Materials Modification & Green Forming Technology Harbin University of Science and Technology

Compared with homogeneous structural materials, gradient structural materials are easier to realize the strengthductility optimization. Research on the strengthening mechanism of different gradient structure materials is a meaningful way to broaden the application of gradient structure materials. In this paper, the AZ31 magnesium alloy plate was rolled by hard plate rolling. The gradient structure was controlled by changing the initial plate thickness. When the initial plate thickness was 4 mm, AZ31 magnesium alloy shows excellent strength and ductility, the tensile strength was 282.2 MPa, and the ductility was 28.4 %. The change of the initial plate thickness changes the stress state which forming a gradient structure with different characteristic layers. The extra strengthening between different characteristic layers improves the properties of gradient structure, which makes the magnesium alloy change from a uniaxial stress state to a multi-axial stress state during the tensile process. The increase of the characteristic layer induces more geometrically necessary dislocation accumulation, improving the gradient structure's strength and ductility. This research provides a new design strategy for the forming and performance optimization of gradient structure magnesium alloy plate by hard plate rolling, which has good industrial production and application potential.

关键词： Hard plate rolling Gradient structure AZ31 magnesium alloy Extra strengthening Geometrically necessary dislocation

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Mainchain Semifluorinated Polymers with Ultra High Molecular Weight via Reaction-enhanced Reactivity of Intermediate(RERI) Mechanism

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Chinese Journal of Polymer science 2023年第5期41卷 760-767,I0009页

作者： Jia-Sheng Wu Wang-Meng Hou Zhi-Jia Liu Yi Shi Yong-Ming Chen School of Materials Science and Engineering Key Laboratory for Polymeric Composite and Functional Materials of Ministry of EducationSun Yat-Sen UniversityGuangzhou 510006China

Achieving the linear polymers with high molecular weight via step-growth polymerization of A2 and B2 monomers is significantly limited by the requirement of strict stoichiometry of two monomers when the reactivity of A and B groups are not changed during the ***,a unique step-growth polymerization based on copper-catalyzed azide-alkyne cycloaddition(CuAAC)with reactionenhanced reactivity of intermediate(RERI)mechanism was developed for the preparation of mainchain semifluorinated polymers with high molecular *** CuAAC polymerization of bis-alkynyl-terminated fluorinated monomers(A2)and 2,2-bis(azidomethyl)propane-1,3-diyl bis(2-methylpropanoate)(BiAz,B2)with RERI effect at different stoichiometric ratio was systematically *** results indicated that the semifluorinated polymers with ultrahigh molecular weight,Mw,MALLS>106 g/mol,could be efficiently synthesized by using excess molar of BiAz *** resultant high-molecular-weight semifluorinated polymers show good thermostability and high *** addition,the glass transition temperature(Tg)of these mainchain semifluorinated polymers could be tuned conveniently due to the bis-alkynyl-terminated comonomers could be consumed completely when excessive BiAz monomers were used in this this step-growth polymerization.

关键词： Semifluorinated polymers Click polymerization Step-growth polymerization

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Design and characterization of a novel Cu_(2.3)Al_(1.3)Ni_(1.7)SnCr_(0.3) multi-principal element alloy coating on magnesium alloy by laser cladding

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Journal of materials science & Technology 2023年第21期152卷 220-236页

作者： Lipeng Jiang Xiufang Cui Guo Jin Zhimin Tian Xin Wen Haoliang Tian Erbao Liu Institute of Surface/Interface Science and Technology Key Laboratory of Superlight Material and Surface Technology of Ministry of EducationCollege of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material Beijing Beijing Institute of Aeronautical MaterialsBeijing 100095China Institute of Defense Engineering AMSPLABeijing 100850China

The evaporation and dilution of substrate seriously limit the performance of laser cladding coatings on magnesium *** order to overcome the above shortcomings,a multi-step ultrasonic assisted laser remelting technology was proposed to improve the performance of the *** this work,a novel Cu_(2.3)Al_(1.3)Ni_(1.7)SnCr_(0.3) multi-principal element alloy coating(MPEAC)was prepared on the surface of mag-nesium *** techniques such as transmission electron microscopy(TEM),electron back scatter diffraction(EBSD)and scanning electron microscopy(SEM)were employed to characterize the microstructure and phase composition of the *** the phase structure and morphology at the interface between the coating and the substrate were also studied via focus ion beam(FIB)and TEM *** addition,the corrosion and wear resistance ability of the coatings were monitored by potentiodynamic polarization(PDP),and electrochemical impedance spectroscopy(EIS),hardness and friction *** results show that Cu_(2.3)Al_(1.3)Ni_(1.7)SnCr_(0.3) MPEAC with ultrasonic assisted is composed of FCC phase and eutectic phases(Cu_(10)Sn_(3) and Cu_(2)Ni_(3)Sn_(3)).Due to the forced convection generated by ultrasonic waves,some Cu and Ni phases are precipitated around Cu_(2)Ni_(3)Sn_(3) phases,which is beneficial to enhance the corrosion *** of the grain refinement effect caused by ultrasonic,the wear resistance of the coating is also ***,ultrasonic vibration can effectively weaken and eliminate the texture density of the Cu_(2.3)Al_(1.3)Ni_(1.7)SnCr_(0.3) MPEAC fabricated by laser cladding.

关键词： Magnesium alloy Multi-principal element alloy coating Ultrasonic assisted laser cladding Corrosion resistance Wear resistance

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