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Influences of Reaction Parameters and Ce Contents on Structure and Properties of Nano-scale Ce-HA Powders

Journal of Materials Science & Technology 2014年第8期30卷 776-781页

作者： l.J.Sun d.G.Guo W.A.Zhao l.y.Wang K.W.Xu State Key laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi'an Jiaotong University Chao Family Comprehensive Cancer Center Department of Pharmaceutical SciencesUniversity of California Irvine Sue and Bill Gross Stem Cell Research Center University of California Irvine The Key laboratory of Bioactive Materials Ministry of EducationCollege of Life SciencesNankai University Xi'an university of Arts and Science

Ce-incorporated apatite（Ce-HA） nano-scale particles with different Ce percentage contents（atomic ratio of Ce to Ce ＋ Ca is 5%,10%and 20%,respectively） were synthesized via a simple wet chemical method in this *** crystal structure,chemical groups,thermal stability,crystal morphologies and crystal sizes of the Ce-HA nano-particles were characterized by X-ray diffraction（XRd）,Fourier transform infrared spectroscopy（FTIR）,and transmission electron microscopy（TEM）.The influences of reaction temperature,reaction time,pH value,and the atomic ratio of Ce to Ce ＋ Ca on the structure and performance of Ce-HA particles were *** results show that the lattice constants,particle sizes,crystallinity and thermal stability of Ce-HA vary with the doped Ce *** the increase of Ce content,the lattice constants of the Ce-HA nano-particles remarkably increase but the particle size,crystallinity and thermal stability gradually *** reaction temperature as well as the reaction time has no significant effect on the properties of the final products,while the pH value has a direct relationship with their final chemical *** obtained Ce-HA nanosize particles possess potential application in preparing artificial bone implants,bone tissue engineering scaffold and other bioactive coatings.

关键词： Cerium Apatite Nano-scale powder Wet chemical approach Biomedical materials

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Molecular dynamics Simulation of Porous layer-enhanced dislocation Emission and Crack Propagation in Iron Crystal

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Journal of Materials Science & Technology 2011年第11期27卷 1025-1028页

作者： d. li F.y. Meng X.Q. Ma l.J. Qiao W.y. Chu department of Physics University of Science and Technology Beijing Beijing 100083 China Corrosion and Protection Center Key Lab of Environmental Fracture （Ministry of Education） University of Science and Technology Beijing Beijing 100083 China

The internal stress induced by a porous layer or passive layer can assist the applied stress to promote dislocation emission and crack propagation, e.9. when the pipeline steel is buried in the soil containing water, resulting in stress corrosion cracking （SCC）. Molecular dynamics （Md） simulation is performed to study the process of dislocation emission and crack propagation in a slab of Fe crystal with and without a porous layer on the surface of the crack. The results show that when there is a porous layer on the surface of the crack, the tensile stress induced by the porous layer can superimpose on the external applied stress and then assist the applied stress to initiate crack tip dislocation emission under lowered stress intensity KI, or stress. To respond to the corrosion accelerated dislocation emission and motion, the crack begins to propagate under lowered stress intensity KI, resulting in SCC.

关键词： Molecular dynamics simulation dislocation emission Crack propagation Porouslayer Stress intensity

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Evolution of the Microstructure and Strength in the Nugget Zone of Friction Stir Welded SiCp/Al-Cu-Mg Composite

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Journal of Materials Science & Technology 2014年第1期30卷 54-60页

作者： d.Wang B.l.Xiao Q.Z.Wang Z.y.Ma Shenyang National laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences university of Science and Technology of China

A 6 mm-thick SiCp/2009AI composite plate was successfully joined by friction stir welding （FSW） using an ultrahard material tool to investigate the evolution of the microstructure and the strength in the nugget zone （NZ）. While some SiC particles were broken up during FSW, most of them rotated in the matrix. large compound particles on the interfaces were broken off during FSW, whereas the amorphous layer and small compound particles remained on the interfaces. The dynamically recrystallized AI grains nucleated on the surface of fractured SiC particles during FSW, forming nano-sized grains around the SiC particles. The yield strength of the NZ decreased slightly due to the variation in the size, shape, and distribution of the SiC particles. The clean interfaces were beneficial to the load transfer between SiC particles and AI matrix and then increased the ultimate tensile strength of the NZ.

关键词： Metal-matrix composites Friction stir welding Microstructure Mechanical properties

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RATIONAl GENERAl SOluTIONS OF HIGHER ORdER AlGEBRAIC OdES

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Journal of Systems Science & Complexity 2013年第2期26卷 261-280页

作者： HuANG yanli NG l X Chu WINKlER Franz School of Computer Science and Software Engineering Tianjin Polytechnic University Research Institute for Symbolic Computation(RISC) Johannes Kepler University department of Mathematics Quy Nhon University

This paper generalizes the method of Ng6 and Winkler （2010, 2011） for finding rational general solutions of a first order non-autonomous algebraic ordinary differential equation （AOdE） to the case of a higher order AOdE, provided a proper parametrization of its solution hypersurface. The authors reduce the problem of finding the rational general solution of a higher order AOdE to finding the rational general solution of an associated system. The rational general solutions of the original AOdE and its associated system are in computable 1-1 correspondence. The authors give necessary and sufficient conditions for the associated system to have a rational solution based on proper reparametrization of invariant algebraic space curves. The authors also relate invariant space curves to first integrals and characterize rationally solvable systems by rational first integrals.

关键词： Algebraic OdE associated system invariant algebraic space curve rational first integral rational general solution.

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Effect of static annealing on superplastic behavior of a friction stir welded Ti-6Al-4V alloy joint and microstructural evolution during deformation

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Journal of Materials Science & Technology 2022年第35期130卷 112-123页

作者： C.l.Jia l.H.Wu P.Xue d.R.Ni B.l.Xiao Z.y.Ma Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Key laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

Structural integration is one of the most critical developing directions in the modern aerospace field,in which large-scale complex components of Ti alloys are proposed to be fabricated via the method of welding + superplastic ***,the undesired strain localization appeared during superplastic deformation of the entire joint has largely hindered the development of this *** our study,a combination process of friction stir welding(FSW) + static annealing+ superplastic deformation was first time proposed to eliminate severe local *** achieve this result,a fully fine lamellar structure was obtained in the nugget zone(NZ) via FSW,which was totally different from the mill-annealed structure in the base material(BM).After annealing at 900℃ for 180 min,the BM and NZ then exhibited the similar elongation of> 500% and similar flow stress at 900 ℃,3 × 10^(-3)s^(-1),which was the precondition for achieving uniform superplastic deformation in the entire ***,the different microstructures in the BM and NZ tended to become the similar equiaxed structure after deformation,which was the result of different microstructural evolution mechanisms in the NZ and *** the NZ,there was a static and dynamic spheroidization of the fully lamellar structure during the process,which could largely reduce the flow softening of the fully lamellar *** the BM,a new view of "langdon-CRSS theory"(CRSS,critical resolved shear stress) was proposed to describe the fragmentation of the coarse equiaxed structure,which established the relationship between grain boundary sliding and intragranular deformation during deformation.

关键词： Friction stir welding Titanium alloys Superplasticity Static annealing Microstructure

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Tuning thermal expansion by a continuing atomic rearrangement mechanism in a multifunctional titanium alloy

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Journal of Materials Science & Technology 2021年第21期80卷 234-243页

作者： d.l.Gong H.l.Wang E.G.Obbard S.J.li R.yang y.l.Hao Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China School of Mechanical Engineering Dongguan University of TechnologyDongguan523808China department of Electrical Engineering and Telecommunications University of New South WalesSydneyNSW2052Australia

As to multifunctional titanium alloys with high strength and low elastic modulus, thermal training is crucial to tune their thermal expansion from positive to negative, resulting in a novel linear expansion which is stable in a wide temperature range. Aided by the high-order Hooke's law of elastic solids,a reversible atomic rearrangement mechanism was proposed to explain the novel findings which are unexpected from typical shape memory alloys. To confirm this continuous mechanism, a Ti-Nb based alloy, which possesses a nanoscale spongy microstructure consisting of the interpenetrated Nb-rich and Nb-lean domains produced by spinodal decomposition, was used to trace the crystal structure change by in-situ high energy synchrotron X-ray diffraction analyses. By increasing exposure time, the overlapped diffraction peaks can be separated accurately. The calculated results demonstrate that, in the nanoscale Nb-lean domains, the crystal structure parameters vary linearly with changing temperature along the atomic pathway of the bcc-hcp transition. This linear relationship in a wide temperature range is unusual for first-order martensitic shape memory alloys but is common for Invar alloys with high-order spin transitions. Furthermore, the alloy exhibits smooth dSC curves free of transformation-induced heat peaks observed in shape memory alloys, which is consistent with the proposed mechanism that the reversible transition is of high-order.

关键词： Coefficient of thermal expansion Multifunctional titanium alloys Spongy microstructure Atomic rearrangement Elastic anisotropy

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PHySICAl SIMulATION BASEd INTEllIGENT SySTEM FOR THE PREdICTION OF SHEET METAl dRAWING CAPABIlITy

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Acta Metallurgica Sinica(English letters) 2000年第2期13卷 451-458页

作者： d.lv d.N.He X.J.Bao y.Q.Zhang X.y.Ruan J.l.Cheng J.y.Jiang National die&Mold CAd Engineering Research Center Shanghai Jiaotong UniversityShanghai 200030China Shanghai Volkswagen Automotive Company limited Shanghai 201805China

With the combination of a new theoretical formula, physical simulation experiments, the technology of artificial neural network and database, an intelligent system for the prediction of sheet metal drawing capability is constructed for the first time. A modified criterion for sheet metal drawing capability is proposed in this paper, namely, the Technological limiting drawing Ratio, TldR = f(R, n, s, t, F, μ,r_d,r_p…). Based on the studies of other scholars, a new formula is derived to predict the TldR in this paper. Then a series of orthogonal physical simulation experiments are designed to investigate the effect of technological parameters on the TldR, and the results are analyzed in the paper. Then the predicting system is constructed with the combination of the theoretical formula, orthogonal experiments, the technology of artifocial neural network and database. The predicted results show good agreements with experimental data, so it can be used to avoid the blindness in the selection of sheet metal before stamping. The system operates under the Windows operating system, and it supports the mechanism of Client/Server as well as Intranet, so the system has high engineering value.

关键词： TldR theoretical analysis physical simulation orthogonal experiments neural network database predicting system

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Relationship between the fatigue behavior and grain structures of an as-extruded Mg-6.2%Zn-0.6%Zr(in wt.%)alloy

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Journal of Materials Science & Technology 2023年第18期149卷 119-126页

作者： B.J.Wang d.K.Xu C.l.Jiang l.y.Sheng E.H.Han School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang 110159China Key laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Binzhou Institute of Technology Binzhou 256606China Shandong Key laboratory of Advanced Aluminium Materials and Technology Binzhou 256606China Shenzhen Institute Shenzhen Key Lab Human Tissue Regenerate&RepairPeking UniversityShenzhen 518057China

Through investigating the tension-tension fatigue behavior of an as-extruded Mg-6.2 wt.%Zn-0.6 wt.%Zr(ZK60)alloy,it revealed that the determined fatigue strength at 107 cycles was quite sensitive to the grain *** them,the fine grain structure had the highest fatigue strength of 130 MPa,whereas the typical“bi-modal”grain structure had the lowest fatigue strength of 110 *** analysis demon-strated that for the fine grain structure,fatigue cracks preferentially nucleated at grain *** the“bi-modal”and coarse grain structures,the fatigue crack initiation was dominated by the cracking along slip bands.

关键词： Mg alloys Grain structure Cyclic slips Fatigue behavior Crack initiation

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A low-cost and High Efficiency Architecture of AES Crypto-engine

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China Communications 2008年第2期5卷 8-15页

作者： Z.F.Zhao d.y.yu l.li Vinno Technologies Inc

The growing market of WPAN has led to an increasingdemand of security measures and devices forprotecting the user data transmitted over the *** Encryption Standards(AES)isthe basic security approach for *** meet thelow cost,low power feature and high security demandof WPAN,a low cost,high efficient AES coreis proposed in this *** achieve low cost,methods of integration and resource sharing are usedin designing a very low-complexity architecture,especially in(inverse)byte substitution(inv)SubBytes)modules and(inverse)mix column(inv)MixColumn)modules,*** more,AESEncryptor and decryptor is integrated into a fullfunctional *** very low-cost andhigh efficiency AES core of IEEE 802.15.4-2006 isdesigned and emulated on Xilinx *** show that this kind of design can be used inresource critical applications,such as smart card,PdA and mobile phones.

关键词： AES S-box Sub-Byte WPAN

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^(199)Sn ANd ^(57)Fe MOSSBAuER SPECTROSCOPIC STudy OF THE MECHANICAlly AllOyEd Fe-Sn AllOyS

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Acta Metallurgica Sinica(English letters) 1998年第5期11卷 335-341页

作者： y.Z.yang y.l.Zhu Q.S.li X.M.Ma y.d.dong y.Z.Chuang Guangdong univ of Technology Guangzhou China

Nanocrystalline supersaturated solid solutions (Sa in Fe) with Sn content less than 50 at. %,and FeSn2 and Fe1.3Sn intermetallic compounds have been prepared by mechanical alloying of Fe and Sn mixture powders with composition of Fe1-xSnx (x≤0.5).The atomic alloying the formation and microstructure, especially the coordination environments, of the resultant alloys have been studied by X-ray diffraction, 57Fe and 119Sn Mossbauer Spectroscopy and diffrrential scanning calorimetry. The Fe and Sn coordination environments and the composition dependence of the hyperfine parameters on the Fe and Sn content have been fully discussed with respect to the solid dissolution alloying, grain refinement, and distortion caused or induced by mechanical alloying.

关键词： mechanical alloying Mossbauer effect nanocrystalline Fe-Sn alloy

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