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MECHANISM FOR DIFFUSION OF BORON IN γ-Fe

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Acta Metallurgica Sinica(English Letters) 1992年第5期5卷 318-323页

作者： yu zongsen CHEN Ning university of science and technology beijing,beijing,china beijing Univ of science and Technology Beijing China

Mechanism for diffusion of B in γ-Fe is believed to be mainly by means of boron-vacancy complexes other than as interstitial atoms *** was made of calculation on the ba- sis of theoretical model proposed by the *** calculated diffusion coefficient of B in γ-Fe after this mechanism is consistent with the experimental *** addition,this is also supported by the non-equilibrium segregation phenomenon of B at grain boundaries of γ-Fe and the lattice constant measurement of Fe-B alloy.

关键词： boron vacancy diffusion non-equilibrium segregation γ-Fe

SIZE DISTRIBUTION AND BEHAVIOUR OF VC PARTICLES IN FERRITIC NODULAR CAST IRON

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Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 92-97页

作者： WANG yu SONG Weixi HAN Qiyong university of science and technology beijing,beijing,china The Institute of Precise and Special New materials, university of science and technology beijing,beijing 100083,china beijing Univ of science and Technology Beijing China

Size distribution and precipitation of VC particles in ferritic nodular cast iron have been examined by techniques of ultrasonic screening,small angle X-ray scattering and chemical *** VC particles are sized over a wide *** superfine ones, dispersed in the ferritic matrix,are the majority.A saturated dispersion with ultrafine VC particles may be approached as the V content increasing in the ***5 seems to play an important role in the precipitation strengthening for ferritic nodular cast iron.

关键词： nodular cast iron ferrite size distribution VC particle

Analysis on Microstructure and Misorientation of Ultrathin Hot Strip of Low Carbon Steel Produced by Compact Strip Production

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Journal of materials science & technology 2002年第6期18卷 501-503页

作者： Hao yu, Yonglin KANG and Jie FUSchool of materials science and Engineering, university of science and technology beijing, beijing 100083, china Sch. of Mat. Sci. and Eng. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The microstructure and misorientation of ultrathin hot strip were analyzed by CSP technology using electron back scattered diffraction (EBSD) method and Autoforge finite element program. The experimental results showed that the finishing hot rolling microstructures were the mixture of recrystallized and deformed austenite. After phase transformation, ferrite grains embody substructures and dislocations, leading to the high strength and relatively low elongation rate of the ultrathin hot strip. The FEM simulation of strain mode and distribution in deformation area has been fulfilled. The simulation results are in good agreement with the theoretical analysis and experimental results.

关键词： CSP Electron back scattered diffraction, Texture, Finite element method

Precipitatation Behavior of FeTiP Phase in High Strength IF Steel

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International Journal of Minerals,Metallurgy and materials 2000年第3期14卷 197-203页

作者： Zisu Zhao, Weimin Mao, Yongning yu (university of science and technology beijing, beijing 100083, china) university of science and technology beijing Beijing 100083 China

The influence of chemical composition and annealing parameters on the behavior of FeTiP precipitation has been investigated. With increasing Ti content the yield strength and tensile strength were reduced, and the tendency of FeTiP precipitation became more remarkable. No FeTiP precipitate was observed and the best mechanical properties have been obtained in the steel sheet, of which the atom ratio of Ti to N is approximately equal to 1. In the temperature range of 700 to 800℃ the FeTiP precipitation could appear easily. The precipitation process was suppressed when the annealing temperature was below 600℃, and the FeTiP phase was dissolved above 900℃. The FeTiP precipitates would inhibit the migration of grain boundaries during the recrystallization in certain extent, and weaken the density of {111} fiber texture, which resulted in the reduction of r value. The relationship between composition and processing parameters, as well as their influence on the mechanical properties is discussed.

关键词： IF steel FeTiP precipitation

A Discussion on Evolution of Microstructures and Influence Factors during Continuous Rolling of Compact Strip Production

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Journal of materials science & technology 2004年第3期20卷 274-278页

作者： Hongbo DONG Yonglin KANG Hao yu department of materials Processing and Controlling, university of science and technology beijing, beijing 100083, china Dept. of Mat. Proc. and Control Univ. of Sci. and Technol. Beijing Beijing 100083 China

The evolution of microstructures and influence factors of ultrathin hot strips of low carbon steel produced by compactstrip production (CSP) techniques were investigated. The steel blocking samples of CSP six-passes were obtained,and microstructures at the different positions of workpiece for each pass were studied. At the same time, anexplicit finite element technique was used to reveal the continuous rolling process. By combining experiment resultswith simulation analysis, the effects of plastic strain, temperature, precipitation and interval time on evolution andrefinement of crystal grains have been investigated. The results are useful for the development of high strength hotstrips.

关键词： CSP Microstructure Strain Temperature Precipitation

Nucleation of Cold Rolled FeCo Alloy during Annealing and Its Influence on the Formation of Recrystallization Texture

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Journal of materials science & technology 2000年第5期16卷 543-545页

作者： Guohui ZHU, Weimin MAO+ and Yongning yu (department of Metal materials, university of science and technology beijing, beijing 100083, china) department of Metal materials University of Science and Technology Beijing Beijing 100083 China

The orientation distribution of recrystallization grains formed during annealing, as well as their misorientation relationship to the deformation matrix in cold rolled FeCo alloy have been investigated. It was found that most of the recrystallization nuclei were located near the boundary area with rather random orientations, and their misorientation angles to the deformation matrix were generally very high. However a few nuclei were also observed inside the deformation grains, to which they had very similar orientations. Therefore the misorientation angles between the nuclei and the deformation matrix were generally very low. The orientation and the misorientation distributions of the nuclei have very strong influence on the recrystallization process which could result in a very weak recrystallization texture. The corresponding mechanism is discussed.

关键词： In Nucleation of Cold Rolled FeCo Alloy during Annealing and Its Influence on the Formation of Recrystallization Texture

Multimedia Data Coding and its Development

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International Journal of Minerals,Metallurgy and materials 2000年第3期14卷 229-232页

作者： Xingye yu, Yang Yang (Information Engineering School, university of science and technology beijing, beijing 100083, china) Information Engineering School University of Science and Technology Beijing Beijing 100083 China

The requirements of data coding in multimedia applications are presented, the current technique of coding and relative standards is introduced, then the work that have been doing is presented, i.e. the wavelet-based coding method and the VE (Visual Entropy)-based coding method. The experiment results prove that these methods have gained a better perceptual quality of a reconstructed image and a lower bit rate. Their performance evaluations are better than JPEG (Joint Photographic Experts Group) coding. Finally, the future topics of study are put forward.

关键词： multimedia data coding MPEG (Moving Picture Experts Group) VE (Visual Entropy)

Magnetic properties and structure of very thin permalloy films

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Journal of university of science and technology beijing 2004年第3期11卷 225-229页

作者： Guanghua yu Haifeng Li Tao Yang Fengwu Zhu materials science and Engineering School, university of science and technology beijing, beijing 100083, china Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

In order to study the magnetic properties and structure of very thinpermalloy films, Ni_(81)Fe_(19) films of 12 nm in thickness were prepared by different instrumentsat an ultrahigh base vacuum and a lower base vacuum. The anisotropic magnetoresistance coefficients(ΔR/R) of Ni_(81)Fe_(19) (12 nm) films reached 1.6 % and 0.6 %, and the coercivities were 127 and334 A/m, respectively. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were usedto study the structure and surface chemical state. The experimental results show that the filmsprepared at the ultrahigh base vacuum have a smoother surface, a bigger grain size and a denserstructure with fewer defects than those prepared at the lower base vacuum.

关键词： NiFe film anisotropic magnetoresistance (AMR) coercivity structure

DISTRIBUTION AND EFFECT OF Ce IN RE BEARING DUCTILE IRON

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Acta Metallurgica Sinica(English Letters) 1992年第6期5卷 419-424页

作者： ZHU Ruihui WANG yu HAN Qiyong SONG Weixi university of science and technology beijing,beijing,china Engineer,Institute of Precise and Special New materials,university of science and technology beijing,beijing 100083,china beijing Univ of science and Technology Beijing China

The dependence of nodularization of graphite upon Ce content in RE bearing nodular cast iron,prepared by directional solidification,has been investigated by electrolytic extraction-radioisotope assay analysis of Ce in each phase of the iron together with measurement of nodulized *** show that the Ce occurs mainly as alloyed form. In the graphite phase,the Ce content is believed to be characterization of *** graphite would completely nodulized only the Ce is over a certain content in graphite phase.

关键词： RE nodular cast iron directional solidification graphite Ce