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Acta Metallurgica Sinica(English Letters) 2005年第4期18卷 525-532页

作者： z. zhang C. Cai F.h. Cao z.N. Gao J.Q. zhang C.N. Cao Department of Chemistry Zhejiang University Hangzhou 310027 China Department of Chemistry Ningxia University Yinchuan 750021 China State Key Laboratory for Corrosion and Protection of Metals Institute of Metal Research The Chinese

The corrosion behavior of pure aluminum in neutral 3.0% （mass fraction） sodium chloride （Na-Cl） solution has been studied using electrochemical impedance spectroscopy （EIS） measurement in conjunction with the scanning electron microscopy （SEM） technique. EIS information on the evolution of pitting corrosion over a period of 15 days has been obtained and analyzed with equivalent circuit technique. The results shown that, during the ensemble constant immersion time, two time constants involved, the high frequency one originated from the protective layer on the corroding surface while the low frequenO, one from the diffusion process or the corrosion reaction and so on. And there existed a period for oxide film to growth and thickening prior to the of the attacking of chloride ions to the substrate. Meanwhile, good relationship between EIS and the material corrosion type/severity has been obtained, which has been interpreted according to the characteristics of corrosion process such as auto acceleration of pitting corrosion and the protection of local anodic reaction to the area around them.

关键词： pure aluminum pitting corrosion electrochemical impedance spectroscopy pit-rnorphology

Empirical models for predicting lateral spreading considering the effect of regional seismicity

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Earthquake Engineering and Engineering Vibration 2012年第1期11卷 121-131页

作者： zhang Jian Yang Changwei john X. zhao Graeme h. Mcgerry Department of Civil Engineering Southwest Jiaotong University Chengdu 610031 China GNS Science Lower Hutt New Zealand

A revised empirical model has been developed for predicting liquefaction-induced lateral spreading displacement （LD） as a function of both response spectral acceleration derived from strong-motion attenuation models and geotechnical parameters from Youd＇s LD data set （Youd website）. This revised model is different from the model of zhang and zhao, which overcame some drawbacks of earlier models for predicting lateral spreading and was primarily used in Japan and the western U.S. The revised model can potentially be applied anywhere if ground shaking （in terms of 5% damped acceleration or displacement response spectra） can be estimated using local strong-motion attenuation relationships. The revised model is examined using data from Japan and the western U.S. and applied to Turkey and New zealand, where the ground shaking is estimated using appropriate strong-motion attenuation relationships for each region. The accuracy of the revised model is evaluated by comparing its predicted lateral displacements with those measured in actual earthquakes. The results show that the revised model can account for the effects of local seismicity on lateral spreading displacements and is comparable with existing prediction models.

关键词： lateral spreading liquefaction strong-motion attenuation

Tizr-base Bulk Metallic Glass with over 50 mm in Diameter

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Journal of Materials Science & Technology 2010年第6期26卷 481-486页

作者： M. Q. Tang h.F. zhang z. W. zhu h.M. Fu A.M. Wang h. Li z.Q. hu Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences 72Wenhua Road Shenyang 110016 China

Low-cost Tizr-base bulk metallic glasses （BMGs）（Ti36.1zr33.2Ni5.8Be24.9）100-xCux （x=5, 7 and g） with a maximum size of over 50 mm in diameter were developed by optimizing the alloy composition. The idea is initiated by selecting a particular microstructure comprising primary β-Ti dendrite and amorphous phase. Afterwards, based on this composition of amorphous phase, a class of Tizr-base bulk metallic glasses was designed step by step to reach the optimum composition range. The glass transition temperature （Tg）, initial crystallization temperature （Tx） and width of supercooled region （AT） of （***33.2Nis.8Be24.9）91Cu9 BMG are 611, 055 and 44 K, respectively. The （Ti36.1zr33.2Ni5.8Be24.9）91Cu9 BMG exhibits low density of 5.541 g·cm-3 and high compressive fracture strength of 1800 MPa, which promises the potential application as structural materials.

关键词： Tizr-base alloy Bulk metallic glass (BMG) Fracture strength

Evolution mechanisms of microstructure and mechanical properties in a friction stir welded ultrahigh-strength quenching and partitioning steel

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Journal of Materials Science & Technology 2022年第7期102卷 213-223页

作者： z.W.Wang J.F.zhang G.M.Xie L.h.Wu h.zhang 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 State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819China

Ultrahigh-strength quenching and partitioning(Q&P) steels have attracted strong interests in the auto manufactory,while the comprehensive understanding in the microstructure and mechanical behavior of their welded joints is highly needed to enrich their *** the present work,it is designed to make an insight into these imperative *** strength Q&P 1180 steel joints to parent metal were successfully fabricated via friction stir welding(FSW) technique under different parameters. Apparent hardening and softening were observed in stir zone(Sz) and heat-affected zone(hAz) respectively,whose microstructures strongly depended on the peak temperature and cooling rate during *** formation of fresh martensite was the main mechanism for the Sz hardening,while the decomposition of metastable phases played key roles in the microhardness drop of the hAz.A heat source zone-isothermal phase transition layer model was proposed to clarify the impregnability of the joint strength under parameter *** dual-phase structure,nano-carbide particles,tempered initial martensite,and ultrafine-grained ferrite synergistically improved the strain hardening ability of the hAz,which eventually resulted in the equal strength FSW joints.

关键词： Ultrahigh-strength Q&P steel Friction stir welding Microstructure Mechanical property Strain hardening

DAMPING BEhAVIOR OF ULTRAFINE-GRAINED PURE ALUMINUM L2 AND ThE DAMPING MEChANISM

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Acta Metallurgica Sinica(English Letters) 2006年第3期19卷 223-227页

作者： z.M. zhang C.J. Xu J.C. Wang h.z. Liu School of Materials Science ＆ Engineering Xi＇an University of Technology Xi＇an 710048 Ghina State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 Ghina

Ultrafine-grained pure aluminum L2 with a mean grain size of 1.01μm was produced by equal channel angular pressing （ECAP） and annealing at 150℃ for 2h. Damping behavior of the alloy was measured using a dynamic mechanical thermal analyzer. The alloy had an excellent damping capacity Q^-1 with the ambient value being 9.8×10^-3 at 1.0hz when the strain amplitude was 2.0×10^-5. The damping behavior of the alloy showed a non-linear damping variation tendency, that is, with an increase in temperature and a decrease of frequency, the damping capacity of the alloy increased. The damping capacity increased with the strain amplitude when the strain amplitude was less than 4.6×10^-5. When the strain amplitude was higher than 4.6×10^-5, the damping capacity became a constant and independent of strain amplitude. The high damping capacity was attributed to dislocation unpinning and a drag of dislocation on pinning points.

关键词： ECAP ultrafine grain damping capacity aluminum alloy

Magnetic and Transport Properties of Mn_(0.98)Cr_(0.02)Te Epitaxial Films Grown on Al_2O_3 Substrates

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Journal of Materials Science & Technology 2014年第2期30卷 103-106页

作者： z.h.Wang D.Y.Geng J.Li Y.B.Li z.D.zhang Shenyang National Laboratory for Materials Science Institute of Metal Researchand International Centre for Materials PhysicsChinese Academy of Sciences Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of Sciences

The epitaxial Mno0.98Cr0.02Te films on single crystal Al2O3 （0001） substrates were prepared by pulsed laser deposition. The X-ray diffraction and scanning electron microscopy results showed that the good continuous epitaxial film was obtained with substrate temperature of 500 ℃. When the substrate temperature reached 700 ℃, the film was island growth and the manganese oxides phase appeared. The temperature dependence of both the magnetization and electrical resistance showed a sharp rise at around 60 K due to the magnetoelastic coupling. The temperature dependence of the electrical resistance of Mno0.98Cr0.02Te provided evidence for a transition from the metallic to semiconducting state at 305 K due to the spin disorder scattering with a large contribution from the influence of magnon drag.

关键词： Magnetic properties Mno0.98Cr0.02Te films X-ray diffraction Epitaxial film

Derimorphisms over Algebras and Applications

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Algebra Colloquium 2023年第2期30卷 193-204页

作者： X.Cao S.h.Liu X.S.Lu z.J.Ye z.R.Yu Y.h.zhang School of Mathematical Sciences Shanghai Jiao Tong University 800 Dongchuan RoadShanghai 200240China MoE Key Lab of Scientific and Engineering Computing Shanghai Jiao Tong University 800 Dongchuan RoadShanghai 200240China

The new concept"derimorphism"generalizing both derivation and homomor-phism is *** a derimorphism is invertible,its inverse is a Rota-Baxter *** general theory of derimorphism is *** classification of all derimorphisms over an associative unital algebra is *** to the nonexistence of nontriv-ial positive derivations,it is shown that nontrivial positive derimorphisms do exist over any pair of opposite orderings over R[x],the lattice-ordered full matrix algebra and upper triangular matrix algebra over a totally ordered field.

关键词： derimorphism Rota-Baxter operator opposite orderings positive derimor-phism

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

An Implicit Block LU-SGS Algorithm-Based Lattice Boltzmann Flux Solver for Simulation of hypersonic Flows

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Advances in Applied Mathematics and Mechanics 2019年第1期11卷 72-90页

作者： z.X.Meng S.z.Li K.Peng W.h.zhang College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China National Innovation Institute of Defense Technology Academy of Military ScienceBeijing 100091China

This paper proposes a stable and efficient implicit block Lower-Upper Symmetric-Gauss-Seidel(LU-SGS)algorithm-based lattice Boltzmann flux solver(LBFS)for simulation of hypersonic *** this method,the finite volume method(FVM)is applied to discretize the Navier-Stokes equations,and the LBFS is utilized to evaluate the numerical flux at the cell *** LBFS,the local solution of discrete velocity Boltzmann equation(DVBE)with the non-free parameter D1Q4 lattice Boltzmann model is adopted to reconstruct the inviscid flux across the cell interface,and the viscous flux is approximated by conventional smooth function *** order to improve the robustness and convergence rate of the simulation for hypersonic flows,especially for problems with complex geometry,the implicit block LU-SGS algorithm is introduced to solve resultant discrete governing equations.A double cone model at Mach number of Ma=9.86 is firstly simulated to validate the proposed scheme,and a hypersonic flight vehicle with wings and rudders at Mach number of Ma=5.56 is then calculated to extend the application in practical engineering *** results show that the proposed scheme could offer a more accurate and effective prediction for hypersonic flows.

关键词： hypersonic flows lattice Boltzmann flux solver implicit block LU-SGS finite volume method

ELECTROChEMICAL STUDY ON ThE LOCALIzED CORROSION OF TWO DIFFERENT TEMPER LY12 ALLOYS

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Acta Metallurgica Sinica(English Letters) 2005年第5期18卷 609-619页

作者： F.h. Cao L. Guo L.J. zhang z. zhang J. Q. zhang Department of Chemistry Yuquan Campus Zhejiang University Hangzhou 310027 China State Key Laboratory for Corrosion and Protection of Metals Institute of Metal Research The Chinese Academy of Sciences Shenyang 110016 China

The corrosion behavior of two different aged LY12 alloys in EXCO （234g/L NaCl, 50g/L KNO3 0.1M hNO3） and MIL-h-600 （35g/L NaCl, 5g/L （Nh4）2SO4） solutions were studied using electrochemical impedance spectroscopy （EIS） in conjunction with SEM technique respectively, and the ph variation of the above accelerated corrosion solution during materials corroding was also measured to characterize the corrosion processes. At the beginning of corrosion, EIS plots exhibited two capacitive arcs in the high frequency range （Cd） and mediate frequency range （ Cf） originating from the original corroded surface and the newly formed interface respectively, and a low frequency inductive loop due to the relaxation phenomenon of reaction intermediates. In the EXCO,solution, the EIS results showed that once the exfoliation corrosion occurred, the inductive loop disappeared. The results also showed that the exfoliation corrosion susceptibility of state T6 is much higher than that of state T3, but the intergranular corrosion susceptibility has a reverse order. Based on the relationship of EIS results with SEM and metalloscopy morphologies of the corroding substrates and physic-chemical meaning of EIS parameters, an index （Cf/Cd） has been proposed to characterize the extent of the localized corrosion, which variation tallies with the real corrosion extent correctly. Meanwhile, good agreement was found between the experimental results and the electrochemical model proposed and, good coherence between the electrochemical features and the distribution type of constituent particles of corroding material was observed.

关键词： electrochemical impedance spectroscope LY12 alloy exfoliation corrosion intergranular corrosion