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PREPARATION AND XRD STUDY OF LITHIUM DEFICIENT Lib COMPOUND

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Acta Metallurgica Sinica(English Letters) 2004年第5期17卷 667-671页

作者： z.j.Liu b.Y.Huang z.Y.Li StateKeyLaboratoryforPowderMetallurgy CentralSouthUniversityChangsha410083China

The Lib compounds in lithium deficient state were prepared by three methods and its crystal structure was investigated by using XRD. It is found that the lattice constant c of the compound will increase step by step with decreasing Li content from 0.2796nm of the normal Lib to 0.2886, 0.2981 and 0.3118nm of the lithium deficient Lib. The change of the lattice constant is reversible.

关键词： Lib compound crystal structure electrode materials X-ray diffraction

A practical model for efficient anti-fatigue design and selection of metallic materials:Ⅰ.Model building and fatigue strength prediction

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journal of Materials Science & Technology 2021年第11期70卷 233-249页

作者： R.Liu P.zhang z.j.zhang b.Wang z.F.zhang Laboratory of Fatigue and Fracture for Materials Shi-changxu Innovation Center for Advanced MaterialsInstitute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China

The high cost and low efficiency of fatigue tests are bottleneck problem for the anti-fatigue design of metallic *** this problem,a theoretical fatigue model is proposed in this study,the possible applications have also been *** results would be introduced in two serial papers,in which the first paper focuses on the model building and the applications on fatigue strength prediction;the second paper put emphasis on the influencing factors of the model parameters and the applications on fatigue strength *** this first paper,a theoretical model is proposed considering both the strength and plastic restrictions of fatigue *** the model builds up a brief relationship among yield strength(Y),tensile strength(T)and fatigue strength(F),it is named as the Y-T-F *** the verification with fatigue strength data covering various kinds of metallic materials and loading conditions,this Y-T-F model exhibits both generality and *** the Y-T-F model,the efficient fatigue strength prediction could be conducted by brief linear fitting and calculation,just through yield strength,tensile strength and several known fatigue strength ***,through its deduced Y-F model,the analytical formula of fatigue strength continuously changing with materials strengthening can be obtained,as well as the maximum value of fatigue strength and corresponding critical yield *** summary,the Y-T-F model would be useful for reducing the fatigue tests,thus providing new possibilities on the efficient anti-fatigue design and selection of metallic materials.

关键词： Yield strength Tensile strength Plasticity Fatigue strength Anti-fatigue design

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Distinct dendritic α phase emerging on the surface of primary α phase in a compressed near-α titanium alloy

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journal of Materials Science & Technology 2018年第4期34卷 666-669页

作者： z.Liu z.b.zhao j.R.Liu Q.j.Wang R.Yang Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

The characteristic of the surface morphology of primary α phase was studied in a deformed near-α tita- nium alloy. Dendritic α phase emerged on the surfaces of primary α phase when the alloy was air-cooled in α ＋β phase field after deformation. The dendritic α grain has the same orientation with its original primary α grain. The formation of the dendritic α phase could be explained by interface instability in epi- taxial growth process of the primary α phase. The dislocations induced by deformation could facilitate the formation of dendritic α phase leading to the dendritic α phase and more obvious with the increase of strain. The growth of dendritic α phase was finally limited by the nucleation of second α phase with cooling.

关键词： Epitaxial growth Dendritic α phase Microstructure Interface instability Hot deformation

Analysis of local crystallographic orientation in an annealed Ti60 billet

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journal of Materials Science & Technology 2019年第4期35卷 591-595页

作者： z.b.zhao z.Liu Q.j.Wang j.R.Liu R.Yang Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

A heterogeneous microstructure in terms of local orientation distribution is often found in near-α titanium alloys. The presence of large regions with similar crystallographic orientation, called ‘macrozones',could drastically decrease the fatigue performance of titanium alloys. The present work reports on the crystallographic orientation of a near-α titanium alloy, Ti60, billet after annealing in an α+β phase *** texture was found to be weak, and no obvious macrozone was found in our measured zone where the variant selection is suppressed. Meanwhile, in-depth electron backscattered diffraction(EbSD) analysis was applied to evaluate the final microstructure, and the mechanisms by which they formed were analyzed.

关键词： Titanium alloys Microstructure Texture Heat treatment EbSD

Deformation behaviors of Cu bicrystals with an inclined twin boundary at multiple scales

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journal of Materials Science & Technology 2017年第7期33卷 698-702页

作者： L.L.Li z.j.zhang P.zhang j.Tan j.b.Yang z.F.zhang Shenyaag National Laboratory for Materials Science lastitute of Metal Research Chinese Academy of Sciences Shenyaag 110016 China

Cu bicrystals of different sizes with a sole twin boundary（Tb） inclined at 45？with respect to the loading direction were deformed under unidirectional and cyclic loading, respectively. It is found that the slip bands（Sbs） parallel to the Tb can be activated near the Tb at all scales without obeying the Schmid＇s *** is concerned with the local stress enhancement in the macroscale while it is more closely related to the scarce dislocation sources in the microscale. Moreover, a wedge-shaped zone formed near the Tb in the microscale ascribed to the limited specimen size.

关键词： bicrystal Micropillar Twin boundary Schmid factors Size effect

MODELING AND EXPERIMENTAL RESEARCH OF FOUR-STRAND LOW-FREQUENCY ELECTROMAGNETIC CASTING ALUMINUM ALLOY

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Acta Metallurgica Sinica(English Letters) 2007年第3期20卷 157-166页

作者： j.C. Li b.F. Wang j.z. Cui School of Materials ＆ Metallurgy Inner Mongolia University of Science and Technology Baotou 014010 China The Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern University Shenyang 110004 China

With the aid of ANSYS software, the effect of different mould external part materials on magnetic flux density in the aluminum melt and magnetic field interaction of four coils applied with same currents were investigated. Calculating results showed that magnetic flux density in the aluminum melt was greatly improved and the magnetic field interaction among different coils was decreased when external part of mould is made of soft magnetic material. based on the finding, a four-strand low-frequency electromagnetic casting 6063 aluminum alloy experiment was carried out in the laboratory . The experiment showed that the surface of the billet was smooth and had no exudations and cold shuts, the as-cast microstructures were fine, uniform, equiaxed, net-globular or globular under low-frequency electromagnetic field. The microstructure becomes finer with increased current value.

关键词： low-frequency electromagnetic casting finite element method aluminum alloy mould

Strategies for improving ductility of ordered intermetallics

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Progress in Natural Science:Materials International 2016年第1期26卷 1-12页

作者： z.b.j.ao j.H.Luan C.T.Liu Center for Advanced Structural Materials Department of Mechanical and Biomedical Engineering College of Science and Engineering City University of Hong Kong

Ordered intermetallics possess attractive high-temperature properties; however, low ductility and brittle fracture limit their use as engineering materials in many cases. This paper provides a comprehensive review on the recent progress in the development of ductile ordered intermetallics and summarizes the strategies used to improve the tensile ductility of ordered intermetallics, including control of ordered crystal structures,engineering grain-boundary structure and chemistry, eliminating environmental embrittlement, microstructure optimization, control of phase stability, and promoting transformation-/twining-induced plasticity. The basic ideas and related mechanisms underlying these ductilizing strategies are discussed. In addition, a brief mention of the current use of intermetallic alloys for structural and corrosion applications is made.

关键词： Ordered intermetallics Ductility Ductilizing strategy Microstructure Alloy design

On the topological number in Kelvin's circulation of inviscid fluids

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Communications in Theoretical Physics 2024年第12期76卷 176-180页

作者： z b Guo State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University

Kelvin's circulation,as a loop integral of the velocity field,is first shown to be equal to Γc=2πΔnΓ1+constant in an inviscid fluid,with Γ1a unit *** integer Δn is interpreted as the number of net 27r-rotations of the velocity vector in one cyclicality along the circulation loop and hence it is a topological *** from the linkage number in the helicity invariant,which only exists in 3D space,the topological number in the circulation invariant is independent of the spatial dimension.A further study reveals that this new topological phase 2πΔn is rooted at the gauge invariance of the circulation and it is a counterpart of the berry's phase in the quantum system.

关键词： berry's phase fluids Kelvin’s circulation topological number

Compressive property and energy absorption characteristic of interconnected porous Mg-zn-Y alloys with adjusting Y addition

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journal of Magnesium and Alloys 2024年第1期12卷 171-185页

作者： j.A.Liu S.j.Liu b.Wang W.b.Sun X.j.Liu z.W.Han College of Materials Science and Engineering Key Laboratory of Automobile Materials(Ministry of Education)Jilin UniversityChangchun 130022PR China Key Laboratory of bionic Engineering(Ministry of Education) College of Biological and Agricultural EngineeringJilin UniversityChangchun130022PR China Weihai Institute for bionics-jilin University Weihai 264205PR China

In this study,interconnected porous Mg-2zn-xY alloys with different phase compositions were prepared by various Y additions(x=0.4,3,and 6 wt.%)to adjust the compressive properties and energy absorption *** characterization methods were then applied to identify the microstructure of the porous Mg-zn-Y and describe the details of the second *** tests were performed at room temperature(RT),200℃,and 300℃to study the impact of the Y addition and testing temperature on the compressive properties of the porous *** experimental results showed that a high Y content promotes a microstructure refinement and increases the volume fraction of the second *** the Y content increases,different Mg-zn-Y ternary phases appear:I-phase(Mg_(3)zn_(6)Y),W-phase(Mg_(3)zn_(3)Y_(2)),and LPSO phase(Mg_(12)znY).When the Y content ranges between 0.4%and 6%,the compressive strength increases from 6.30MPa to 9.23 MPa,and the energy absorption capacity increases from 7.33 Mj/m^(3)to 10.97 Mj/m^(3)at RT,which is mainly attributed to the phase composition and volume fraction of the second ***,the average energy absorption efficiency is independent of the Y *** addition,the compressive deformation behaviors of the porous Mg-zn-Y are altered by the testing *** compressive strength and energy absorption capacity of the porous Mg-zn-Y decrease due to the softening effect of the high temperature on the *** deformation behaviors at different temperatures are finally observed to reflect the failure mechanisms of the struts.

关键词： Porous magnesium Rare earth elements Microstructure Compressive behavior Energy absorption characteristic