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EFFECTS OF COMBINED ADDITIONS OF TUNGSTEN AND MOLYBDENUM ON THE CREEP PROPERLIES OFFe_3Al-BASED ALLOYS

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Acta Metallurgica Sinica(English Letters) 2000年第6期13卷 1136-1140页

作者： x.q. yu and Y.S. Sun (Department of Materials Science and Engineering, Southeast University, Nanjing 210096, China) Dep. of Materials and Eng. Southeast Univ. Nanjing 210096 China

Effects of combined additions of tungsten and molybdenum on the creep properties of Fe3AI-based alloys have been investigated. Results show that combined additions of tungsten and molybdenum increase significantly the creep rupture life of the Fe3Al base alloys at high temperature. TEM analysis of the alloys containing tungsten plus molybdenum indicates that both solid-solution strengthening and precipitation harden- ing make the significant increase of creep rupture life.

关键词： Fe3Al creep property tungsten molybde8

NUMERICAL SIMULATION OF TEMPERATURE FIELD DURING MAGNETIC FIELD qUENCHING

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Acta Metallurgica Sinica(English Letters) 2005年第6期18卷 773-776页

作者： M. H. Liu Z.H. Li x.q. yu J.R. Chen Kunming University of Science ＆ Technology Kunming 650093 China Hebei University of Science ＆ Technology Shijiazhuang 050018 China

Based on the theories of the heat transfer, the principle of phase transformation and the theory of electric and magnetic field, the mathematical model of transient temperature field involving phase transformation during magnetic field quenching is established. The heat exchange equation including magnetic field is founded. The finite element equation is set up. The distributing of transient temperature on the coupling effects of heat and magnetism is obtained. With test and measurement, the results show that after magnetic field quenching, cooling velocity is decreased, cooling curve is flatten out, and the hardness is slightly raised.

关键词： magnetic field quenching specific heals abrupt change non-linear heatconduction equation finite element equation

MICROSTRUCTURES AND OxIDATION RESISTANCE OF Fe_3Al WELD OVERLAY

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Acta Metallurgica Sinica(English Letters) 2001年第4期14卷 253-256页

作者： x.G. Mi x.q. yu, Y.S. Sun and J.R. Sun Department of Materials Science and Engineering, Southeast University, Nanjing 210096, China Dept. of Mat. Sci. Southeast Univ. Nanjing 210096 China

Using the Fe3Al electrode through manual arc surfacing (MAS), Fe3Al coatings were deposited on the stainless steel substrate. The microstructures, hardness and oxidation resistance of the weld overlay were investigated. The results show that crack-free overlays can be obtained when pre-heating the substrate at 500°C and postweld heat treatment at 700°C are used. Elements of Al, Cr and Ni, etc. transfer between the substrate and the overlay, but this does not influence the microhardness of the substrate and the Fe3Al overlay. Oxidation tests show that the Fe3Al overlay has excellent oxidation resistance in comparison with the stainless steel substrate at 800°C and 900°C.

关键词： Aluminum Intermetallics Iron Microstructure Oxidation resistance

Acute and chronic excitotoxicity in ischemic stroke and late-onset Alzheimer's disease

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Neural Regeneration Research 2025年第7期20卷 1981-1988页

作者： Shan Ping yu Emily Choi Michael qJiang Ling Wei Department of Anesthesiology Emory University School of MedicineAtlantaGAUSA Center for Visual and Neurocognitive Rehabilitation Atlanta Veterans Affairs Medical CenterDecaturGAUSA

Stroke and Alzheimer's disease are common neurological disorders and often occur in the same *** comorbidity of the two neurological disorders represents a grave health threat to older *** review presents a brief background of the development of novel concepts and their clinical *** activity of glutamatergic N-methyl-D-aspartate receptors and N-methyl-D-aspartate receptor-mediated Ca^(2+)influx is critical for neuronal *** ischemic insult induces prompt and excessive glutamate release and drastic increases of intracellular Ca^(2+)mainly via N-methyl-D-aspartate receptors,particularly of those at the extrasynaptic *** Ca^(2+)-evoked neuronal cell death in the ischemic core is dominated by necrosis within a few hours and days known as acute ***,mild but sustained Ca^(2+)increases under neurodegenerative conditions such as in the distant penumbra of the ischemic brain and early stages of Alzheimer's disease are not immediately toxic,but gradually set off deteriorating Ca^(2+)-dependent signals and neuronal cell loss mostly because of activation of programmed cell death *** on the Ca^(2+)hypothesis of Alzheimer's disease and recent advances,this Ca^(2+)-activated“silent”degenerative excitotoxicity evolves from years to decades and is recognized as a unique slow and chronic *** N-methyl-D-aspartate receptor subunit GluN3A,primarily at the extrasynaptic site,serves as a gatekeeper for the N-methyl-D-aspartate receptor activity and is neuroprotective against both acute and chronic *** stroke and Alzheimer's disease,therefore,share an N-methyl-D-aspartate receptor-and Ca^(2+)-mediated mechanism,although with much different time *** is thus proposed that early interventions to control Ca^(2+)homeostasis at the preclinical stage are pivotal for individuals who are susceptible to sporadic late-onset Alzheimer's disease and Alzheimer's disease-related

关键词： Ca^(2+)hypothesis cognitive deficits hyperactivity late-onset Alzheimer's disease neurodegeneration N-methyl-D-aspartate receptors N-methyl-D-aspartate receptor subunits pathogenesis preventive treatment

EFFECT OF CERIUM ION IMPLANTATION ON THE AqUEOUS CORROSION BEHAVIOR OF ZIRCONIUM

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Acta Metallurgica Sinica(English Letters) 2004年第6期17卷 812-816页

作者： D.q.Peng x.D.Bai q.G.Zhou x.W.Chen R.H.yu x.Y.Liu DepartmentofMaterialsScienceandEngineering TsinghuaUniversityBeijing100084ChinaManuscriptreceived9September2003

In order to study the influence of cerium ion implantation on the aqueous corrosion behavior of zirconium, specimens were implanted by cerium ions with a dosage range from 1×1016 to 1×1017 ions/cm2 at about 150℃, using MEVVA source at an acceler ative voltage of 40kV. The valence of the surface layer was analyzed by x-ray photo- electron spectroscopy (xPS); Three-sweep potentiodynamic polarization measurement was employed to value the aqueous corrosion resistance of zirconium in a 0.5mol/L H2SO4 solution. It was found that a remarkable decline in the aqueous corrosion behavior of zirconium implanted with cerium ions compared with that of the as-received zirconium. Finally, the mechanism of the corrosion resistance decline of the cerium-implanted zirconium is discussed.

关键词： zirconium corrosion resistance cerium ion implantation potentio- dynamic polarization x-ray photoelectron spectroscopy (xPS)

Tensile Elastic Behavior of a Zr-Cu-Ag-Al Bulk Metallic Glass

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Journal of Materials Science & Technology 2014年第6期30卷 595-598页

作者： q.P.Cao J.B.Jin q.yu x.D.Wang D.x.Zhang Y.Jiang J.Z.Jiang International Center for New-Structured Materials (ICNSM) State Key Laboratory of Silicon MaterialsDepartment of Materials Science and Engineering Zhejiang University Department of Mechanical Engineering University of Nevada Reno NV 89557 USA State Key Laboratory of Modern Optical Instrumentation Zhejiang University

Tensile elastic behavior of bulk Zr46（Cu4.5/5.5Ag1/5.5）46Al8 metallic glass was experimentally investigated. It exhibited linear and non-linear time-independent elastic deformation with a demarcative stress of approximately 500 MPa within the timescale in the present work, and repeated loading-unloading before yielding did not alter stress-strain relationship. The pure linear elastic strain limit is 0.6%, significantly lower than 2% as generally reported, but still much higher than 0.1% observed for typical crystalline alloys. Deviation from linear elastic behavior at stresses higher than 500 MPa is explained here as a macroscopic manifestation of local fluctuations in elastic strain, which becomes pronounced at stresses higher than the critical value. The occurrence of non-linear elasticity is possibly also related to the sinusoidal relationship between shear stress and atomic displacement.

关键词： Bulk metallic glass Tension test Elastic-plastic deformation

An in-vitro Investigation of Iron-Containing Hydroxyapatite/Titanium Composites

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Journal of Materials Science & Technology 2011年第6期27卷 546-552页

作者： q. Chang H.q. Ru D.L. Chen x.Y. yue L. yu C.P. Zhang Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education) Northeastern University Shenyang 110004 China Department of Mechanical and Industrial Engineering Ryerson University 350 Victoria Street Toronto Ontario M5B 2K3 Canada

The in-vitro biological behavior of a newly-developed iron-containing hydroxyapatite/titanium（HA/Ti） composite was investigated by immersing the composites in the simulated body fluid（SBF） for up to 5 *** addition of iron was observed to have a significant influence on the in-vitro biological behavior of the *** obtained results revealed that the stability of the composites in the physiological solution was markedly *** solubility decreased in the order of pure HA,HA/5（Ti-33Fe）,and HA/15（Ti33Fe）.Precipitation occurred on the surface of HA/5（Ti-33Fe） composite,showing a good combination of physiostability with bioactivity,while HA/15（Ti-33Fe） composite exhibited superior physiostability since there was no obvious change on the surface of HA/15（Ti-33Fe）.

关键词： Hydroxyapatite composite Iron Titanium Simulated body fluid Biological behavior

Excellent strength-ductility combination in Co_(36)Cr_(15)Fe_(18)Ni_(18)Al_(8)Ti_(4)Mo_(1)multi-principal element alloys by dual-morphology B2 precipitates strengthening

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Journal of Materials Science & Technology 2023年第3期134卷 60-66页

作者： x.S.Liu R.Li x.F.Fan q.q.Liu x.Tong A.x.Li S.xu H.Yang S.B.yu M.H.Jiang C.Huo P.F.yu M.T.Dove G.Li State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China College of Computer Science Sichuan UniversityChengdu 610065China School of Physical and Chemical Sciences Queen Mary University of LondonMile End RoadLondon E14NSUnited Kingdom School of Mechanical Engineering Dongguan University of TechnologyDongguan 523808China

Precipitation strengthening provides one of the most widely-used mechanisms for strengthen-ing multi-principal-element alloys(MPEAs).Here,we report dual-morphology B2 precipitates in Co_(36)Cr_(15)Fe_(18)Ni_(18)Al_(8)Ti_(4)Mo_(1)MPEA obtained by thermo-mechanical *** microscopy charac-terization reveals that the dual-morphology B2 precipitates are either recrystallized B2 particles formed at the grain boundaries or triple junctions with recrystallization process,or rod-like within the non-recrystallized FCC *** dual-morphology B2 precipitates enhance the yield strength and ultimate tensile strength up to 1120 MPa and 1480 MPa,*** work suggests the mechanical proper-ties of the alloy can be optimized by B2 precipitation strengthening to meet the needs of engineering applications.

关键词： Multi-principal element alloys B2 precipitates Heterogeneous nucleation Precipitation strengthening

THEORETICAL STUDY OF GIANT MAGNETO-IMPEDANCE IN AMORPHOUS FILMS WITH LONGITUDINAL MAGNETIC ANISOTROPY

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Acta Metallurgica Sinica(English Letters) 2000年第4期13卷 995-1000页

作者： yu, J.q. Zhou, Y. Cai, B.C. Zhao, x.L. Shanghai Jiaotong Univ Shanghai China

Giant magneto-impedance (MI) effect in thin films with longitudinal magnetic anisotropy was studied theoretically. The effective permeability of films as a function of external magnetic field Ha, anisotropy field and other parameters of films was presented by Landau-Lifshitz-Gilbert theory. The theoretical results agree well with the experimental data, which shows a strong dependence of the impedance on the applied magnetic field.

关键词： Electric currents Magnetic anisotropy Magnetic fields Skin effect