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Journal of university of science and technology beijing 2004年第3期11卷 240-244页

作者： Hong zhang Jianxin Xie zidong wang 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

Pure copper rods containing continuous columnar crystals were fabricatedusing the downward CUS (Continuous Unidirectional Solidification) equipment. When the technologicalparameters were set as the ranges of mould temperature 1100-1300℃, cooling distance (the distancefrom the exit of the cast mould to the start point of cooling) 10-20 mm, casting speed 0.2-2.5 mm/s,cooling water (20-25℃) volume 1000-1320 L/h, and when these parameters matched reasonably, the CUSprocess was performed stably, and pure copper rods containing continuous columnar crystals withbright and smooth surface were produced. The dendritic arm spacing of the crystals in copper rodsdecreased with increasing the casting speed. The results of the texture by X-ray diffractionanalysis showed that the rods has strong fiber texture.

关键词： copper continuous unidirectional solidification mould temperature castingspeed microstructure texture

Nonlinear Theory on Dynamic Controlling Interface Patterns DuringSolidification of a Dilute Binary Alloy

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International Journal of Minerals,Metallurgy and materials 1999年第4期13卷 253-258页

作者： zidong wang Hanqi Hu(Material science and engineering school, university of science and technology beijing, beijing 100083, china) Material science and engineering school University of Science and Technology Beijing Beijing 100083 China

In non-equilibrium nonlinear region, the nonlinear equations of time dependence of perturbation amplitude at the solid/liquidinterface during solidification of a dilute binary alloy are established on the base of assuming that there is local equilibrium at the solid/liquid interface and considering that curvature, temperature and composition at the solid/liquid interface which are related to the perturbation amplitude are nonlinear. As a result, patterns at the solid/liquid interface during solidification process, which is from nonsteadystate to steady state can be controlled by these nonlinear equations.

关键词： nonlinearity solidification, dilute binary alloy, dynamic control

Dislocation Densites of Deformed Steel Sheets Based on Positron Annihilation

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International Journal of Minerals,Metallurgy and materials 1998年第1期12卷 47-50页

作者： Yonglin Kang Xianjin wang (materials science and engineering school, university of science and technology beijing, beijing 100083, china) materials science and engineering school University of Science and Technology Beijing Beijing 100083 China

The variation regularity of dislocation densites of some deformed steel sheets under three kinds of strainpaths as uniaxial tension, plane strain and equal biaxial stretching was investigated by means of positron lifetimespectrum and Doppler-broadening techniques. The results show that the increasing rate of dislocation densites isrelated to the plastic strain path. A relationship between the increasing rate of micro-defects, macro-instability andforming limits during the process of steel sheet forming was got based on analyzing the mechanism of dislocationdensity increasing under different stress-strain condihons.

关键词： positron annihilation dislocation steel sheet strain path

Sol-gel Preparation and Infrared Radiation Property of Boron-substituted Cordierite Glass-ceramics

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Journal of materials science & technology 2010年第5期26卷 445-448页

作者： Shuming wang and Fenghua Kuang school of materials science and engineering,university of science & technology beijing,beijing 100083,china [a] school of materials science and engineering university of science & technology beijing beijing 100083 china

Boron for aluminum substitution in the cordierite structure has been examined by sol-gel preparation of different samples along the compositional junction Mg2Al4-xBxSi5O18 with x=0,0.5,1,*** increasing the x value from 0 to 1.5 the crystallization behavior changed *** amount B2O3 doping can promote the sintering of amorphous cordierite gel,effectively restrain the precipitation of μ-cordierite and enhance the crystallization of α-*** substitution of B3＋ for Al3＋ in cordierite crystal structure can effectively improve the near-infrared spectral emissivity of this cordierite based glass-ceramics.

关键词： Sol-gel Glass-ceramics Infrared radiation B3+ substitution Solid solution

Microstructural Features During Strain Induced Ferrite Transformation in 08 and 20Mn Steels

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Journal of university of science and technology beijing 2001年第2期8卷 105-110页

作者： Ping Yang, Feng-e Cui, Fuming wang (materials science and engineering school, university of science and technology beijing, beijing 100083, china) (Metallurgy school, university of science and technology beijing, beijing 100083, china) Univ Sci & Technol beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China Univ Sci & Technol beijing Met Sch Beijing 100083 Peoples R China

The microstructure evolution during strain induced ferrite transformation was followed in thermal-simulation tests of clean 08 and 20Mn steels. The influences of carbon equivalence and initial austenite grain size on ferrite grain refinement and the volume fraction of ferrite during straining were inspected. The results revealed that the accelerating effect of ferrite transformation by strain was increased as the carbon equivalence decreased. However, finer ferrite grains were obtained at higher carbon content. At strain of similar to1.5 ferrite grains less than 3 mum and 2 mum can be obtained in 08 and 20Mn steels respectively. Whereas the ferrite grain refinement in 08 steel was due to both effects of strain induced transformation and ferrite dynamic recrystallization, that in 20Mn was mainly due to strain induced transformation. Heavy strain can produce fine ferrite grains in coarse austenite grained 08 steel, but it would lead to band microstructure in coarse austenite grained 20Mn.

关键词： clean carbon steel strain induced transformation grain refinement ferrite dynamic recrystallization

Annealing Texture Evolution of Ti-IF Steel during Batch Annealing

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International Journal of Minerals,Metallurgy and materials 1998年第3期12卷 175-179页

作者： Jing Shi Xianjin wang(Material science and engineering school, university of science and technology beijing, beijing 100083, china) Material science and engineering school University of Science and Technology Beijing Beijing 100083 China

Texture development and recrystallization behavior of Ti-IF steel during Batch Annealing (BA) were investigared with X-ray diffraction and EBSP in lab, and the results were compared with research work on continu ous annealing (CA) with rapid heating rate. The basic tendencies are similar that eary nucleation takes place in ND fibers, RD fibers are consumed at the end of recrystallization, and ND texture dominates over annealing texture. However, the detailed texture transformation during batch annealing is different and somewhat more compicated than tha in rapid-heating process. Moreover, misorientation plays an important role in texture transformation of BA In addition, the results of EBSP are consistent with that of ODF well.

关键词： Ti-IF steel texture batch annealing X-ray diffraction EBSP

Refinement of packet size in low carbon bainitic steel by special thermo-mechanical control process

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Journal of university of science and technology beijing 2004年第3期11卷 221-224页

作者： Chengjia Shang Xuemin wang Shanwu Yang Xinlai He 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

The packet size of bainitic steel can be refined by a specialrelaxation-precipitation-control phase transformation (RFC) technology. When processed by RPCprocess, the low carbon bainitic steel composes of two kinds of main intermediate transformationphases. One is ultra-fine lath-like bainitic ferrite and the lath is less than 1μm in width andabout 6 μm in length; the alignment of laths forms a refined packet, and the size of packets isabout 5-7 μm in length and about 3-4μm in width. The other is acicular structure. The morphologyand distribution of these acicular structures are influenced by relaxation process, the thin andshort acicular structures cut the prior austenite grain and refine the bainitic packet size. For theoptimum relaxation time, the packet size can be refined to the finest. The mechanical propertiesare influenced by relaxation time and the 800 MPa grade low carbon bainitic steel with excellenttoughness can be obtained by RPC process.

关键词： packet size refinement bainitic steel RPC process

In Situ Studies of Deformation and Fracture in Sputtering Copper Film

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International Journal of Minerals,Metallurgy and materials 2000年第1期14卷 38-41页

作者： Jinxu Li Yimin Zeng Yanbin wang Wuyang Chu materials science and engineering school, university of science and technology beijing, beijing 100083, china materials science and engineering school University of Science and Technology Beijing Beijing 100083 China

Nanocrystalline copper films were prepared by sputtering and then in situ straining experiments were performed using a trans- mission electron microscope. Macroscopically, these copper films exhibited very low ductili... 详细信息

关键词： in situ straining, deformation fracture nanocrystalline copper film

Wear characteristics of spheroidal graphite roll WC-8Co coating produced by electro-spark deposition

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Rare Metals 2010年第2期29卷 174-179页

作者： wang Jiansheng, MENG Huimin, YU Hongying, FAN Zishuan, and SUN Dongbai school of materials science and engineering, university of science and technology beijing, beijing 100083, china school of materials science and engineering University of Science and Technology Beijing

Electro-spark deposition（ESD） was adopted for preparing high property coatings by depositing WC-8Co cemented carbide on an spheroidal graphite roll *** microstructure and properties of the coating were investigated by X-ray diffraction（XRD）, scanning electron microscopy（SEM） with energy dispersive X-ray（EDX） and ball-disc configuration wear *** results show that nanosized particles and amorphous structures prevail in the coating which is metallurgically bonded to the *** microstructures of the transition zone include columnar structure and equiaxed *** primary phases of the coating contain W2C, W6C2.54, Fe3W3C, and *** results of abrasive test show that the coating has low friction coefficients（μaverage = 0.18） and the wear mechanisms are mainly abrasive wear, fatigue wear, and oxidation *** maximum microhardness value of the coating is about 17410 N/*** study reveals that the electro-spark deposition process has better coating quality and the coating has high wear resistance and hardness.

关键词： electro-spark deposition WC/Co coatings wear resistance microstructure

Numerical prediction of the incremental melting and solidification process

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Journal of university of science and technology beijing 2003年第4期10卷 50-54页

作者： Jun wang, Chengchang Jia, and Sheng Yinmaterials 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

A mathematical formulation is applied to represent the phenomena in theincremental melting and solidification process (IMSP), and the temperature and electromagneticfields and the depth of steel liquid phase are calculated by a finite difference technique using thecontrol volume method. The result shows that the predicted values are in good agreement with theobservations. In accordance with the calculated values for different kinds of materials anddifferent size of molds, the technological parameter of the IMS process such as the power supply andthe descending speed rate can be determined.

关键词： incremental melting and solidification process (IMSP) numerical prediction electromagnetic field temperature field technological parameter