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Tensile and shearing behaviors of the particle raft

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Acta Mechanica Sinica 2021年第6期37卷 904-909,I0001页

作者： P.C.Zuo h.yu J.L.Liu Z.J.Wen College of Pipeline and Civil Engineering China University of Petroleum(East China)Qingdao266580China School of Science China University of Petroleum(East China)Qingdao266580China Key Laboratory of Mining Disaster Prevention and Control Shandong University of Science and TechnologyQingdao266590China

The particle raft is a two-dimensional condensed soft matter,which is composed of hydrophobic solid particles floating on a liquid *** this study,we have realized to conduct tension and shear experiments on the particle raft by using the self-assembled loading *** crack initiation and propagation are observed by the camera,and the curve of the non-dimensional force with respect to the displacement is *** experimental results have been compared with the particle flow code 3D(PFC3D)simulation,and they are in excellent *** indicates that the particle raft possesses mechanical properties between solid and *** findings provide some inspirations on engineering new devices and new materials at the microscale.

关键词： Particle raft Tension Shear Crack Force–displacement curve

Effects of fibers on expansive shotcrete mixtures consisting of calcium sulfoaluminate cement,ordinary Portland cement,and calcium sulfate

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第2期10卷 212-221页

作者： h.yu L.Wu W.V.Liu Y.Pourrahimian School of Mining and Petroleum Engineering Department of Civil and Environmental Engineering University of Alberta

The mining industry often uses shotcrete for ground stabilization. however, cracking within shotcrete is commonly observed, which delays production schedules and increases maintenance costs. A possible crack reduction method is using expansive shotcrete mixture consisting of calcium sulfoaluminate cement(CSA), ordinary Portland cement(OPC), and calcium sulfate(CS) to reduce shrinkage. Furthermore, fibers can be added to the mixture to restrain expansion and impede cracking. The objective of this paper is to study the effects of nylon fiber, glass fiber, and steel fiber on an expansive shotcrete mixture that can better resist cracking. In this study, parameters such as density, water absorption, volume of permeable voids, unconfined compressive strength(UCS), splitting tensile strength(STS), and volume change of fiber-added expansive mixtures were determined at different time periods(i.e. the strengths on the 28 th day, and the volume changes on the 1 st, 7 th, 14 th, 21 st, and 28 th days). The results show that addition of fibers can improve mixture durability, in the form of decreased water absorption and reduced permeable pore space content. Moreover, the expansion of the CSA-OPC-CS mixture was restrained up to50% by glass fiber, up to 43% by nylon fiber, and up to 28% by steel fiber. The results show that the STS was improved by 57% with glass fiber addition, 43% with steel fiber addition, and 38% with nylon fiber addition. The UCS was also increased by 31% after steel fiber addition, 26% after nylon fiber addition, and16% after glass fiber addition. These results suggest that fiber additions to the expansive shotcrete mixtures can improve durability and strengths while controlling expansion.

关键词： Shotcrete Restrained expansion Fibers Calcium sulfoaluminate cement(CSA) Ordinary Portland cement(OPC) Calcium sulfate(CS)

Selective conversion of CO_(2)to CO using earth abundant tin modified copper gas diffusion electrodes

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Materials Reports(Energy) 2023年第2期3卷 154-163,I0004页

作者： Preetam K.Sharma Shahid Rasul Da Li Eileen h.yu Department of Chemical Engineering Loughborough UniversityLoughboroughLE113TUUK Faculty of Engineering and Environment Northumbria UniversityEllison PlNewcastle Upon TyneNE18STUK State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyHarbin150090China

Earth-abundant copper-tin(CuSn)electrocatalysts are potential candidates for cost-effective and sustainable production of CO from electrochemical carbon dioxide reduction(eCO_(2)R).however,the requirement of highoverpotential for obtaining reasonable current,low Faradaic efficiencies(FE)and low intrinsic catalytic activities require the optimisation of the CuSn nanoarchitecture for the further advancement in the *** the current work,we have optimised Sn loading on Cu gas diffusion electrodes(GDEs)by electrochemical spontaneous *** with various Sn loadings were tested in a three-chamber GDE reactor to evaluate their CO_(2)reduction *** best performance of 92%CO Faradaic efficiency at a cathodic current density of 120 mA cm^(-2)was obtained from the 20 min Sn deposited Cu_(2)O sample operated at-1.13 V *** electrocatalyst had~13%surface coverage of Sn on Cu GDE surface,and had Sn in oxide form and copper in metallic *** catalyst also showed stable performance and was operable for>3 h under chronoamperometric *** surface of the GDE reduces from Cu2O to Cu during eCO_(2)R and goes further reconstruction during the eCO_(2)*** study demonstrates the potential of Cu-Sn for selective CO production at high current densities.

关键词： Electrochemical CO_(2)reduction Cu-Sn binary Catalyst Optimising loading Selective CO production Surface reconstruction

The effect of Co and Cr substitutions for Ni on mechanical properties and plastic deformation mechanism of FeMnCoCrNi high entropy alloys

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Journal of Materials Science & Technology 2020年第13期47卷 146-155页

作者： h.F.Zhang h.L.Yan h.yu Z.W.Ji Q.M.hu N.Jia Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Material Science and EngineeringNortheastern UniversityShenyang 110819China State Key Lab Rolling&Automat Northeastern UniversityShenyang 110819China Institute of Metal Research Chinese Academy of ScienceShenyang 110016China Shen Yang University of Technology Shenyang 110870China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China

The elastic constants,ideal tensile strength(ITS),stacking fault energy(SFE),lattice constant and magnetic moment of FeMnCoCrNi high entropy alloys with varying Co and Cr contents at 0 and 300 K were systematically investigated by first-principle *** the alloys with Co substitution for Ni,at both temperatures the elastic stability of the face-centered cubic(fcc)phase,bulk elastic modulus(B),Young’s modulus(E),shear modulus(G)and ITS increase monotonically with increasing Co ***,the Cauchy pressure(Cp),Pugh ratio(B/G),Poisson ratio(v),Zener anisotropy ratio(AZ)and elastic anisotropy ratio(AVR)decrease *** SFE also decreases with the increase of Co,resulting in the change of plastic deformation mechanism from dislocation slip to mechanical twinning,and then to hcp-martensitic *** elucidates the underlying mechanism of the effect of Co addition on the strength and micromechanical behavior of FeMnCoCrNi *** with Co,the Cr substitution for Ni leads to the more complex change of elastic constants and *** increase of Cr shows the similar effect on SFE and deformation mechanism as that of *** variation of valence electron concentration and magnetism affect the *** increase of either Co or Cr leads to the reduced magnetic moments of Fe and *** could be responsible for the monotonic decrease of both lattice constant and SFE as the Co content ***,for the Cr addition case,multiple factors may affect the evolution of lattice constant and *** findings shed light on the deformation mechanism of the alloys with different compositions.

关键词： high entropy alloys First-principle calculations Elastic constants Ideal tensile strength Stacking fault energy

Design and optimization of the composition and mechanical properties for non-equiatomic CoCrNi medium-entropy alloys

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Journal of Materials Science & Technology 2023年第8期139卷 232-244页

作者： J.X.Yan Z.J.Zhang P.Zhang J.h.Liu h.yu Q.M.hu J.B.Yang Z.F.Zhang Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering Chongqing Jiaotong UniversityChongqing 400074China chool of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China School of Information Science and Engineering Shenyang University of TechnologyShenyang 111003China

The development of multi-principal element alloys(MPEAs,also called as high-or medium-entropy al-loys,hEAs/MEAs)provides tremendous possibilities for materials ***,designing MPEAs with desirable mechanical properties confronts great challenges due to their vast composition *** this work,we provide an essential criterion to efficiently screen the CoCrNi MEAs with outstanding strength-ductility *** negative Gibbs free energy difference△E_(FCC-BCC)between the face-centered cubic(FCC)and body-centered cubic(BCC)phases,the enhancement of shear modulus G and the decline of stacking fault energy(SFE)γ_(isf)are combined as three requisites to improve the FCC phase stability,yield strength,deformation mechanisms,work-hardening ability and ductility in the *** effects of chemical composition on△E_(FCC-BCC),G andγisf were investigated with the first principles calculations for Co_(x)Cr_(33)Ni_(67-x),Co_(33)Cr_(y)Ni_(67-y)and Co_(z)Cr_(66-z)Ni_(34)(0≤x,y≤67 and 0≤z≤66)*** on the essential criterion and the calculation results,the composition space that displays the neg-ative Gibbs free energy difference△E_(FCC-BCC),highest shear modulus G and lowest SFEγ_(isf)was screened with the target on the combination of high strength and excellent *** this context,the optimal composition space of Co-Cr-Ni alloys was predicted as 60 at.%-67 at.%Co,30 at.%-35 at.%Cr and 0 at.%-6 at.%Ni,which coincides well with the previous experimental evidence for Co_(55)Cr_(40)Ni_(5)*** valid-ity of essential criterion is further proved after systematic comparison with numerous experimental data,which demonstrates that the essential criterion can provide significant guidance for the quick exploitation of strong and ductile MEAs and promote the development and application of MPEAs.

关键词： Medium-entropy alloys First-principles calculations Phase stability Stacking-fault energy Strength Ductility

Tailoring precipitation/properties and related mechanisms for a high-strength aluminum alloy plate via low-temperature retrogression and re-aging processes

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Journal of Materials Science & Technology 2022年第25期120卷 15-35页

作者： L.G.hou h.yu Y.W.Wang L.You Z.B.he C.M.Wu D.G.Eskin L.Katgerman L.Z.Zhuang J.S.Zhang State Key Laboratory for Advanced Metals&Materials University of Science&Technology BeijingBeijing 100083China BCAST Brunel University LondonKingston LaneUxbidge Middlesex UB83PHUnited Kingdom Institute of mineral resources Chinese Academy of Geological SciencesBeijing 100037China Nanjing Advanced Transportation Equipment New Technology Research Institute Nanjing 211800China Tomsk State University Tomsk634050Russian Federation Katgerman Aluminium Technology van Beuningenlaan 102334CC LeidenNetherlands Department of Materials Science and Engineering Delft University of TechnologyMekelweg 22628CD Delftthe Netherlands

The retrogression and re-aging(RRA)processes,aimed mainly at tailoring intergranular precipitates,could significantly improve the corrosion resistance(i.e.,stress corrosion cracking resistance)without considerably decreasing the strength,which signifies that an efficient control of the size,distribution and evolution of intergranular and intragranular precipitates becomes critical for the integrated properties of the(mid-)thick high-strength Al alloy *** to RRA process with retrogression at200℃ (T77),this study investigated the impact of a modified RRA process(MT77)with lower retrogression temperatures(155-175℃ )and first-stage under-aging on the properties of a high-strength AA7050 Al alloy,in combination with detailed precipitate *** study showed that the strength/microhardness of the RRA-treated alloys decreased with raising retrogression temperature and/or prolonging retrogression time,along with the increased electrical *** rapid responsiveness of microstructure/property typical of retrogression at 200℃ was obviously postponed or decreased by using MT77 process with longer retrogression time that was more suitable for treating the(mid-)thick *** the other hand,higher retrogression temperature facilitated more intragranularηprecipitates,coarse intergranular precipitates and wide precipitate free zones,which prominently increased the electrical conductivity alongside a considerable strength loss as compared to the MT77-treated *** the preferred MT77 process,the high strength approaching T6 level as well as good corrosion resistance was ***,though a relatively homogeneous through-thickness strength was obtained,some small discrepancies of properties between the central and surface areas of an 86-mm thick 7050 Al alloy plate were observed,possibly related to the quenching *** precipitate evolution and mechanistic connection to the properties were discussed and reviewed for high-strengt

关键词： Aluminum alloy heat treatment Precipitation Strength Grain boundary

ANALYSIS ON ThE BEhAVIOR OF PRECIPITATES IN ULTRA-ThIN hOT STRIP OF PLAIN LOW CARBON STEEL PRODUCED BY COMPACT STRIP PRODUCTION

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Acta Metallurgica Sinica(English Letters) 2002年第4期15卷 375-379页

作者： h.yu,Y.L.Kang,h.B.Dong,D.L.Liu and J.FuUniversity of Science and Technology Beijing, Beijing 100083, China Manuscript received 10 October 2001 in revised form 25 January 2002 Univ. of Sci. and Technol. Beijing Beijing 100083 China

This paper investigated the mechanism of precipitation and its influence upon prop-erties of ultra-thin hot strips of low carbon steel produced by CSP techniques using experiment and thermodynamics theory. The experimental results show that there are lots of fine and dispersive precipitates in microstructures. By analysis, most of aluminum nitrides are in grains, while coexisted precipitates of MnS are along grain boundaries. Coexisted precipitates compose cation-vacancy type oxides such as Al2O3 in the core, while MnS is at the fringe of surface. The precipitation behavior of AIN and MnS in the hot strip is studied by thermodynamic calculation. At last, implica-tions between strengthening effect and techniques are analyzed using obtained solubility products.

关键词： CSP precipitation thermodynamics strengthening

Mechanistic Study into the hypervalent Iodine-Catalyzed Difluorination of Alkenes

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Mechanistic Study into the Hypervalent Iodine-Catalyzed Difl...

Mechanistic Study on Ni-Catalyzed Silylation of Aryl Methyl Ethers

中国化学会第十二届全国物理有机化学学术会议

作者： Z.Xu Q.Zhang h.yu Y.Fu hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Urban Pollutant ConversionAnhui Province Key Laboratory of Biomass Clean EnergyiChEMDepartment of ChemistryUniversity of Science and Technology of China Department of Chemistry and Centre for Atomic Engineering of Advanced Materials Anhui University Institute of Industry & Equipment Technology Hefei University of Technology

＜正＞Organofluorine compounds are of great importance in modern organic *** the past years,the hypervalent iodine-catalyzed reaction has been demonstrated to be an efficient method to construct organofluorine compoun...

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Mechanistic Study on Ni-Catalyzed Silylation of Aryl Methyl ...