检索结果-南通市图书馆

STRUCTURAL DETERMINATION OF TITANIUM-OXIDE NANOPARTICLES BY X-RAY ABSORPTION SPECTROSCOPY

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 53-57页

作者： z.Y. Wu J. zhang K. Ibrahim M.I. Abbas g. Li Y. Tao T.D. Hu F.q. Liu H.J. qian Y.N. Xie q.H. zhang L. gao z.z. Chen Beijing Synchrotron Radiation Facility Institute of High Energy Physics The Chinese Academy of Sciences

As a potential application of titanium-oxide nanoparticles, it is extremely important to investigate a detailed picture of the surface and interior structural properties of nanocrystalline materials, such as rutile and anatase with diameters 7.0 and 4.5nm, respectively. X-ray absorption spectroscopy has been used to identify the local Ti environment and related electronic structure. We combine the experimental results at the Ti edge in both bulk and nano-crystals to determine the lattice distortion in terms of differently characteristic preedge features and the variation in the multiple-scattering region of X-ray absorption near-edge structure (XANES) spectra. The relationship between the transition peaks and the surface-to volume ratio is also discussed.

关键词： X-ray absorption near edge structure nano particle transition metal oxide

EFFECT OF LOW-FREqUENCY ELECTROMAgNETIC FIELD ON THE AS-CASTINg MICROSTRUCTURES AND MECHANICAL PROPERTIES OF HDC 2024 ALUMINUM ALLOY

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2008年第3期21卷 205-210页

作者： q.F. zhu z.H. zhao J.z. Cui Y.B. zuo F. qu Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern Univer- sity Shenyang 110004 China

The influences of the low frequency electromagnetic field on the horizontal direct chill casting process were investigated experimentally. Ingots of 2024 aluminum alloy with a cross size of 40 mm× 200 mm were produced by the conventional horizontal chill casting process and low frequency electromagnetic horizontal chill casting processre- spectively. The as-cast structures and the mechanical property of the ingots were examined. The results showed that the low frequency electromagnetic field could sub- stantially refine the microstructures and pronouncedly reduce the macrosegregation in the horizontal direct chill casting process. Moreover, the surface quality of the ingot was prominently improved by the low frequency electromagnetic field. The fracture strength and elongation percentage of the ingot was increased with the low frequency electromagnetic field.

关键词： Horizontal direct chill casting Low frequency electromagnetic field 2024 aluminum alloy Microstructures Macrosegregation

FATIgUE CRACK gROWTH FEATURE OF Fe-Cr-Ni MATRIX COMPOSITE REINFORCED BY TITANIUM CARBIDE PARTICULATE AT 1023K

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1999年第6期12卷 0-0,0-0+0-0页

作者： z. F. wan X.D. Hui g.q. Yuan Y. S. Yang X.C Chen Shandong University of Technology Jinan 250061 China Institute of Metal Research The Chinese Academy of Sciences Shenyang 110015 China Institute of Physics The Chinese Academy of Sciences Beijing 100080 China

The initiation and propagation of the short fatigue crack in a 10vol% titanium carbide particulate reichreed cast Fe-26Cr-14Ni mathe coopsite at 1023K were *** is shown that the titanium carbide particulate may hinder the crack propagation and fatigue fracture of the composite. The relationships between fatigue crack propagation rate and stress intensity factor are da/dN=4.2×10-c(△K)4 for the matrix alloy and da/dN=1.4×10-19(△K)c for the composite. The fatigue thresholds of the composite and mathe alloy are 78 and 3.2MPa.m1/2, respectively. Microcracks initiate at the intedece between titanium carbide particulate and austenite and then propagate in carkide particles. The fracture sudece of the composite shows a distinct transition from wavy and serated cleavage near the threshold regime to striation-type splitting in the stable fatigue crack propagation stage and to a veined morphology characteristic in unstable rapid region.

关键词： fatigue crack initiation and propagation Fe-Cr-Ni matrix composite titanium carbide particulate

Irradiation-induced homogeneous plasticity in amorphous/amorphous nanolaminates

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第22期54卷 70-77页

作者： L.Huang z.q.Chen P.Huang X.K.Meng F.wang State Key Laboratory for Mechanical Behavior of Material School of Materials Science and EngineeringXi'an Jiaotong UniversityXi'an710049China Institute of Materials Engineering National Laboratory of Solid State MicrostructuresCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210023China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi'an Jiaotong UniversityXi'an710049China

Achieving homogeneous plastic deformation in metallic glasses is a long-standing goal yet to be solved in materials science. Here we investigate the effect of ion irradiation on the plastic deformation behavior of zrCu/zrCuNiAlSi amorphous/amorphous nanolaminates(A/ANLs) via nanoindentation testing. The experimental results indicate a dramatic change in deformation mode from multiple shear banding events to homogeneous compressive deformation before and after ion irradiation on the A/ANLs in the areas underneath the indenter. Ion irradiation-induced changes of both fraction and distribution of free volume inside each constituent layer and interfacial state in the A/ANLs may be responsible for the unusual homogeneous deformation behavior. Our results suggest that the mechanical property of A/ANLs could be modified by tuning both the inner and interfacial structure via ion irradiation.

关键词： Metallic glasses Ion irradiation Plastic deformation Nanolaminates Interface

Synthesis and Characterization of Fe_(50)Cr_(14)Mo_(14)C_(14)B_6gd_2 Bulk Amorphous Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2010年第9期26卷 783-786页

作者： M. Iqbal J.I. Akhter H.F. zhang z.q. Hu Physics Division Pakistan Institute of Nuclear Science &: Technology P.O. Nilore Islamabad Pakistan Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China

Bulk amorphous steel having 7 mm thickness was synthesized to evaluate its thermal stability and mechanical *** steel was synthesized by Cu mold casting technique using 1-2N pure *** of the material was done by X-ray diffraction,differential scanning calorimetry and scanning electron *** activation energies were calculated by Kissinger equation and it was found that the steel had better stability against *** properties like Vicker s hardness,nanohardness,elastic modulus and elastic recovery of as-cast and annealed samples were *** was concluded that the present steel had good glass-forming ability（gFA） and mechanical properties.

关键词： Bulk amorphous steels Activation energy glass-forming ability Mechanical properties

PROPERTIES OF MgB_2 FILMS FABRICATED ON COPPER CATHODES BY ELECTROCHEMICAL TECHNIqUE

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2008年第5期21卷 351-354页

作者： H.z. Yang X.g. Sun W.q. Huang M.L. Li X.M. Yu B.S. zhang Y. qi q. zhao Institute of Materials Physics and Chemistry School of Sciences Northeastern University Shenyang 110004 China Key Laboratory for Anisotropy and Texture of Materials Ministry of Education Northeastern University Shenyang 110004 China Department of Applied Physics School of Sciences Shenyang University of Technology Shenyang 110178 China

An electrochemical technique has been introduced and applied to fabricate superconducting MgB2 films in molten salts. MgCl2, Mg（BO2）2, NaCl, and KCl were used as electrolyte, graphite was used as the anode, and copper was used as the cathode, respectively. X-ray diffraction （XRD） analysis was chosen to investigate the phase composition and crystallinity of the films at different electrolysis temperatures. Stan- dard four-probe technique and SqUID were applied to investigate the temperature dependence of resistance （R-T） properties and magnetic properties of the films, respectively. The results indicate that MgB2 films have been fabricated on the copper cathodes, and superconducting transition takes place close to 50 K.

关键词： MgB2 film Electrochemistry Cu cathode

THE EFFECTS OF NEgATIVE BIAS AND FLUX RATIO ON THE PROPERTIES OF TiN THIN FILMS FORMED BY FILTERED CATHODIC ARC PLASMA TECHNIqUE

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 369-374页

作者： Y.J.zhang P.X.Yan z.g.Wu W.W.zhang J.wang q.J.Xue DeparunentofPhysics LanzhouUniversitryLanzhou730000China DeparunentofPhysics LanzhouUniversitryLanzhou730000China／／StateKeyLaboratoryofSolidLubricationInstituteofChemicalPhysicsTheChineseAcademyofSciencesLanzhou730000China StateKeyLaboratoryofSolidLubrication InstituteofChemicalPhysicsTheChineseAcademyofSciencesLanzhou730000China

The filtered cathodic vacuum-arc (FCVA) technique is a supplementary and alterna tive technique with respect to convendtional physical and chemical vapour deposi tion which can remove macro-particles effectively and make the deposition proces s at ambient temperature. In this work, high quality TiN thin films were deposi ted on silicon substrates at low temperature using the improved filtered cathodi c arc plasma (FCAP) technique. AFM, XRD, TEM were employed to characterize the T iN thin films. The effects of the negative substrate bias on the grain size, pre ferred crystalline orientation, surface roughness of TiN thin films were discuss ed.

关键词： TiN filtered cathodic arc plasma preferred orientation

NUMERICAL INVESTIgATION OF STRAIgHT-LINE LASER FORMINg UNDER THE TEMPERATURE gRADIENT MECHANISM

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2006年第2期19卷 144-150页

作者： Y.J. Shi H. Shen z.q. Yao J. Hu School of Mechanical and Power Engineering Shanghai Jiaotong University Shanghai 200030 China

Laser forraing is a new flexible and dieless forming technique. To achieve the high accuracy forming, the temperature gradient mechanism （TgM） is studied. In the analysis of TgM, the plate bends about x-axis and about y-axis as well. To understand the deformation trend, the numerical simulation of deformation of plate is conducted by choosing different laser powers, laser spot diameters, scanning speeds, lengths, widths and thicknesses. From the results of simulation, it can be seen that the laser spot diameter, the scanning speed, laser power and thickness of plate play dominant roles in the laser forming process. However, the bending angles αx and αy show different trends with the variation of parameters. In addition, in comparison with above four parameters, the effect of length and width of plate on the beading angle may be neglected, but their effects are significant for the bending radius R.

关键词： laser forming temperature gradient mechanism metal plate

Influence of Rotor Iron Bridge Position on DC-winding-induced Voltage in Wound Field Switched Flux Machine Having Partitioned Stators

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electrical Engineering 2021年第3期7卷 20-28页

作者： zhongze Wu z.q.zhu Chao wang Wei Hua Kai wang Wentao zhang School of Electrical Engineering Southeast UniversityNanjing 210096China Department of Electronic and Electrical Engineering University of SheffieldSheffield S102TNUK College of Automation Nanjing University of Aeronautics and AstronauticsNanjing 211106China

In this study,the influence of the position of the rotor iron bridge on the DC-winding-induced voltage pulsation in a partitioned stator wound field switched flux machine is *** and finite element(FE)analyses show that both the open-circuit and on-load DC-winding-induced voltages can be minimized by positioning the rotor iron bridge adjacent to the inner air gap closer to the DC *** is due to a smoother inner air-gap magnetic reluctance while maintaining the average electromagnetic torque at 92.59%of the maximum *** analyzed machine with the rotor iron bridge adjacent to the inner air gap is prototyped,and the experimental results validate the analytical and FE results.

关键词： DC winding induced voltage flux switching iron bridge partitioned stator switched flux wound field