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Nano Research 2023年第8期16卷 11012-11017页

作者： Shuaishuai Chen Huaqiang Fu Yunfa Si Xueyu Liu Zhe Wang Yixue Duan Zixin Zhang Hao Feng Xin Zhao Daping He State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Hubei Engineering Research Center of RF-Microwave Technology and Application Wuhan University of TechnologyWuhan 430070China School of Science Wuhan University of TechnologyWuhan 430070China

Facile preparation of additive-free inks with both high viscosity and high conductivity is critical for scalable screen printing of wireless electronics,yet very challenging.MXene materials exhibit excellent conductivity and hydrophilicity,showing great potential in the field of additive-free inks for screen printing.Here,we demonstrate the synthesis of additive-free two-dimensional(2D)titanium carbide MXene inks,and realize screen-printed MXene wireless electronics for the first time.The viscosity of MXene ink is solely regulated by tuning the size of MXene nanosheet without any additives,hence rendering the printed MXene film extremely high conductivity of 1.67×10^(5) S/m and fine printing resolution down to 0.05 mm on various flexible substrates.Moreover,radio frequency identification(RFID)tags fabricated using the additive-free MXene ink via screen printing exhibit stable antenna reading performance and superb flexibility.This article,thus offers a new route for the efficient,low-cost and pollution-free manufacture of printable electronics based on additive-free MXene inks.

关键词： size effect additive-free MXene ink screen printing wireless electronics radio frequency identification(RFID)

size effect of fracture characteristics for anisotropic quasi-brittle geomaterials

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International Journal of Mining Science and Technology 2023年第2期33卷 201-213页

作者： Cunbao Li Dongchao Yang Heping Xie Li Ren Jun Wang Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization Institute of Deep Earth Sciences and Green EnergyShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Deep Engineering Sciences and Green Energy College of Civil and Transportation EngineeringShenzhen UniversityShenzhen 518060China MOE Laboratory of Deep Earth Science and Engineering Sichuan UniversityChengdu 610065China

Understanding the size effect exhibited by the fracture mechanism of anisotropic geomaterials is important for engineering practice. In this study, the anisotropic features of the nominal strength, apparent fracture toughness, effective fracture energy and fracture process zone(FPZ) size of geomaterials were first analyzed by systematic size effect fracture experiments. The results showed that the nominal strength and the apparent fracture toughness decreased with increasing bedding plane inclination angle.The larger the specimen size was, the smaller the nominal strength and the larger the apparent fracture toughness was. When the bedding inclination angle increased from 0° to 90°, the effective fracture energy and the effective FPZ size both first decreased and then increased within two complex variation stages that were bounded by the 45° bedding angle. Regardless of the inherent anisotropy of geomaterials,the nominal strength and apparent fracture toughness can be predicted by the energy-based size effect law, which demonstrates that geomaterials have obvious quasi-brittle characteristics. Theoretical analysis indicated that the true fracture toughness and energy dissipation can be calculated by linear elastic fracture mechanics only when the brittleness number is higher than 10;otherwise, size effect tests should be adopted to determine the fracture parameters.

关键词： size effect Inherent anisotropy Fracture toughness Fracture energy effective FPZ size Quasi-brittle geomaterials

size-effect on Ni electrocatalyst:The case of electrochemical benzyl alcohol oxidation

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Nano Research 2023年第1期16卷 202-208页

作者： Jian Zhong Yongli Shen Pei Zhu Shuang Yao Changhua An Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion School of Chemistry and Chemical EngineeringTianjin University of TechnologyTianjin 300384China Tianjin Key Laboratory of Advanced Functional Porous Materials Institute for New Energy Materials&Low-Carbon TechnologiesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China

The nanoparticles(NPs)of Ni with different sizes endows its distinctive physical and chemical properties,which represents a typical strategy for the development of high-performance catalysts.However,the size effect of metallic Ni-NPs on electrocatalytic performance remains ambiguous.Herein,the Ni-NPs with different sizes supported on nitrogen doped carbon(NC)has been synthesized by controlling the pyrolysis temperature,leading to the synthesis of Ni@NC-500(8.3 nm),Ni@NC-280(1.9 nm)and Ni@NC-200(1.0 nm).The electrooxidation of benzyl alcohol(BA)over these nanocatalysts shows the yield of benzoic acid was 99%,82%,55%on Ni@NC-280,Ni@NC-200 and Ni@NC-500,respectively.The experimental and theoretical simulation demonstrate that the difference in the adsorption strength of reactant molecules by Ni-NPs is responsible for their different performance,where the Ni@NC-280 exhibits an optimal adsorption configuration between Ni@NC-280 electrode and BA.This work provides a new angle for designing and synthesizing efficient electrocatalysts,which may be extended to the exploration of various promising electrocatalytic systems.

关键词： size effect electro-oxidation Ni nanoparticles benzyl alcohol

size effect on the microstructure, phase transformation behavior, and mechanical properties of NiTi shape memory alloys fabricated by laser powder bed fusion

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Journal of Materials Science & Technology 2023年第26期157卷 200-212页

作者： Hao Jiang Xiebin Wang Rui Xi Guichuan Li Huiliang Wei Jiangwei Liu Bo Zhang Sergey Kustov Kim Vanmeensel Jan Van Humbeeck Guoqun Zhao Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China Department of Materials Engineering University of Leuven(KU Leuven)Heverlee B3001Belgium School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China School of Energy and Power Engineering Shandong UniversityJinan 250061China Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection Jinan 250101China Departament de Física Universitat de les Illes BalearsCra Valldemossa km 7.5Palma de Mallorca E07122Spain

In this work,NiTi samples with different thicknesses(0.15-1.00 mm)were fabricated by laser powder bed fusion(LPBF)under variable scanning speeds(500-1200 mm s^(-1)).The densification behavior,phase transformation behavior,and mechanical properties of the sample with different thicknesses are studied.The results indicate a strong size effect in the LPBF-fabricated NiTi alloy.The decrease of the sample thickness results in(i)the increase of porosity,(ii)the decrease of the number of adhered NiTi powder particles at the surface,(iii)the monotonous decrease of the martensitic transformation temperatures(MTTs),and(iv)the decrease of the shape recovery temperature.The influence of sample thickness on the melt-pool behavior,and thus the microstructure and performance of NiTi alloys are discussed.It is suggested that the melt-pool is deeper and narrower in the thin samples than in the thick samples.We conclude that,apart from the LPBF process conditions,the sample dimensions have also to be considered to fabricate NiTi structures with predictable properties.

关键词： Shape memory alloy NiTi Additive manufacturing Laser powder bed fusion size effect

size effect of deformation nanotwin bundles on their strengthening and toughening in heterogeneous nanostructured Cu

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Science China(Technological Sciences) 2021年第1期64卷 23-31页

作者： YOU ZeSheng LUO ShuSen LU Lei Herbert Gleiter Institute of Nanoscience Nanjing University of Science and TechnologyNanjing 210094China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

Herein, we fabricated a heterogeneous nanostructured Cu with deformation nanotwin bundles(NTBs) embedded in a matrix of nanograins by means of dynamic plastic deformation at liquid nitrogen temperature. We conducted fracture mechanical measurements to investigate the effect of longitudinal length of the NTBs on their strengthening and toughening. Results suggest that an increase in the NTB length had a marginal influence on the tensile strength;however, it remarkably promoted both fracture initiation toughness and crack growth toughness. Longer NTBs are more effective not only in intrinsically enhancing crack tip plasticity by suppressing the strain localization and void nucleation but also in serving as crack bridges behind the crack front to extrinsically resist the fracture by shielding the crack tip.

关键词： fracture toughness nanotwins J-integral size effect toughening mechanism

size effect in the Al3Sc dispersoid-mediated precipitation and mechanical/electrical properties of Al-Mg-Si-Sc alloys

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Journal of Materials Science & Technology 2020年第22期54卷 78-84页

作者： Ruihong Wang Shengyu Jiang Bao'an Chen Zhixiang Zhu School of Materials Science and Engineering Xi'an University of TechnologyXi'an710048PR China State Key Laboratory of Advanced Power Transmission Technology Global Energy Interconnection Research Institute Co.Ltd.Beijing102209PR China

A significant size effect is found in the Al3 Sc dispersoid-mediated precipitation in an Al-Mg-Si-Sc alloy.When the Al3 Sc dispersoid size smaller than about 40 nm,β " precipitates nucleate directly on the coherent dispersoids and grow by sacrificing the latter.While the dispersoid size greater than^40 nm,Q' and U2 phases are additionally produced that nucleate on the dislocations induced by the semi-/incoherent dispersoids.Mechanical and electrical properties are highly sensitive to the Al3 Sc dispersoid-tuned precipitation.The co-precipitation of β",Q' and U2 phases leads to an obvious improvement in hardness and simultaneously in electrical conductivity.

关键词： Al-Mg-Si-Sc alloy Al3Sc dispersoids Precipitation size effect Hardness and conductivity

Grain size effect on the assembly quality of micro-scaled barrel formed by microforming

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Advances in Manufacturing 2024年第1期12卷 19-32页

作者： Dien Hu Jieyichen Fang Feng Zeng Ming-Wang Fu Department of Mechanical Engineering Research Institute of Advanced ManufacturingThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongPeople’s Republic of China Xiamen Yulong Machinery Co.Ltd. Xiamen361023FujianPeople’s Republic of China

In this research,a method employing micro-extrusion was designed to produce the micro-scaled barrel-shaped parts with complex geometrical features to study the feasibility of the proposed microforming method and its grain size effect on the formability of the complicated internal features in terms of deformation behavior,material evolution,accuracy of dimensions and final components quality.The results reveal that the deformation behavior is highly affected by grain size and becomes unpredictable with increased grain size.In addition,assembly parameters including feature dimension,tolerance and coaxiality also vary with grain size,and the variation of grain size needs to be accommodated by different assembly types,viz.,clearance fit or transition fit.From the microstructural evolution aspect,it was identified there were two dead zones and four shear bands,and the formation of these deformation zones was barely affected by the variation in grain size.Though bulges,cracks,and fracture induced voids were observed on the surface of the final components,tailoring the microstructure of the working material with finer grains could significantly avoid these defects.This study advances the understanding of forming microparts by extrusion processes and provides guidance for microforming of similar microparts.

关键词： Microformed part size effect Extrusion Microstructural evolution Dimensions Assembly accuracy

Strong size effect on deformation twin-me diate d plasticity in body-centered-cubic iron

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Journal of Materials Science & Technology 2023年第13期144卷 235-242页

作者： Ligong Zhao Guoxujia Chen He Zheng Shuangfeng Jia Kaixuan Li Renhui Jiang Lei Li Ying Zhang Huayu Peng Peili Zhao Ziyang Huang Jianbo Wang School of Physics and Technology Center for Electron MicroscopyMOE Key Laboratory of Artificial Micro-and Nano-structuresand Institute for Advanced StudiesWuhan UniversityWuhan 430072China Suzhou Institute of Wuhan University SuzhouJiangsu 215123China Wuhan University Shenzhen Research Institute ShenzhenGuangdong 518057China

Deformation twinning serves as an important mode of plastic dissipation processes in nanoscale body-centered cubic(BCC)metals,but its origin and spatio-temporal features are mysterious.Here,applying in situ tensile experiments,we report a strong size effect on mediating the twinning behaviors and twin boundary(TB)-dislocation interaction mechanisms in BCC iron(Fe)nanowires(NWs).There exists a critical diameter(d)of∼2.5 nm,above which the deformation twinning rather than dislocation slip dominates the plasticity.Unlike the traditional reflection TBs,the intermediate isosceles TBs are consis-tently observed as mediated by the 1/12partial dislocations.Moreover,we uncover two distinct TB-related deformation mechanisms,including twin variant re-orientation and TB cracking for NWs with d17 nm,respectively.Further molecular dynamics and statics simulations provide the basic underlying mechanisms for size-dependent plasticity,which have been largely overlooked in previous experimental investigations.Our findings highlight the importance of grain size in mediating the deformation behaviors in Fe,serving as possible guidance for exploring single-crystalline and poly-crystalline Fe-based materials(e.***.steel)with optimized mechanical performance.

关键词： size effect Full dislocation,Isosceles twin boundary Twin variant rotation TB cracking

Insights into the size effect of ZnCr_(2)O_(4)spinel oxide in composite catalysts for conversion of syngas to aromatics

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Green Energy & Environment 2023年第2期8卷 530-537页

作者： Yi Fu Youming Ni Wenhao Cui Xudong Fang Zhiyang Chen Zhaopeng Liu Wenliang Zhu Zhongmin Liu National Engineering Laboratory for Methanol to Olefins Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian116023LiaoningChina University of Chinese Academy of Sciences Beijing100049China

Direct conversion of syngas to aromatics(STA)over oxide-zeolite composite catalysts is promising as an alternative method for aromatics production.However,the structural effect of the oxide component in composite catalysts is still ambiguous.Herein,we investigate the size effect by selecting ZnCr_(2)O_(4)spinel,as a probe oxide,mixing with H-ZSM-5 zeolite as a composite catalyst for STA reaction.The CO conversion,aromatics selectivity and space-time yield(STY)of aromatics are all significantly improved with the crystal size of ZnCr_(2)O_(4)oxide decreases,which can mainly attribute to the higher oxygen vacancy concentration and thus the rapid generation of more C1oxygenated intermediate species.Based on the understanding of the size-performance relationship,ZnCr_(2)O_(4)-400 with a smaller size mixing with H-ZSM-5 can achieve32.6%CO conversion with 76%aromatics selectivity.The STY of aromatics reaches as high as 4.79 mmol g_(cat)^(-1)h^(-1),which outperforms the previously reported some typical catalysts.This study elucidates the importance of regulating the size of oxide to design more efficient oxidezeolite composite catalysts for conversion of syngas to value-added chemicals.

关键词： size effect Syngas conversion Aromatics ZnCr_(2)O_(4)oxide H-ZSM-5 zeolite

Influence of mandrel-cores filling on size effect of cross-section distortion of bimetallic thin-walled composite bending tube

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Chinese Journal of Aeronautics 2023年第3期36卷 421-435页

作者： Yingxia ZHU Miaomiao WAN Wei CHEN Yun WANG Wenbin TU Fan XU School of Mechanical Engineering Jiangsu UniversityZhenjiang 212013China School of Mechanical Engineering Guilin University of Aerospace TechnologyGuilin 541004China

Two new size factors of cross-section hollow coefficient and bending degree are introduced to reveal the size effect of bending forming of bimetallic composite tube.Hollow coefficient and bending degree can limit the commonly used bent tube to the size description range of(0,2.00).The evolution laws of the cross-section distortion forms in the hollow coefficient-bending degree interval are revealed as well as the action of the mandrel-cores on the size effect.Results show the mandrel-cores filling can expand the forming limit of the bent tube,but also bring two other forming defects of wrinkle and rupture.The identification factor(hollow coefficient multiply bending degree)provides a method for querying the cross-section distortion forms of all composite bending tubes.In the identification factor interval(0,1.00),the distribution area of bending forming defects of the composite tube is continuous.The thin-walled composite bending tube collapses when identification factor in(0,0.39),wrinkles when identification factor in[0.39,0.50),and ruptures when identification factor in[0.50,1.00).The mathematical model of size effect is derived,by which the average cross-section distortion rate is found to distribute like a radial leaf in the hollow coefficient-bending degree qualified forming space.The best forming zone is hollow coefficient 0.46-0.68,and bending degree 0.25-0.47.

关键词： Bending Bimetallic composite tube Cross-section distortion size factor size effect Mandrel