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Reactive Diffusion Bonding of SiCp/Al Composites by Insert Powder Layers with Eutectic Composition

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Journal of materials science & technology 2005年第5期21卷 779-781页

作者： Jihua HUANG Yueling DONG, Jiangang ZHANG, Yun WAN and Guoan ZHOUSchool 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 Beijing 100083 China

Mixed Al-Si and Al-Cu powders were investigated as insert layers to reactive diffusion bond SiCp/6063 metal matrix composite （MMC）. The results show that SiCp/6063 MMC joints bonded by the insert layers of the mixed Al-Si and Al-Cu powders have a dense joining layer of high quality. The mass transfer between the bonded materials and insert layers during bonding leads to the hypoeutectic microstructure of the joining layers bonded by both the mixed Al-Si and Al-Cu powders with eutectic composition. At fixed bonding time （temperature）, the shear strength of the joints by both insert layers of the mixed Al-Si and Al-Cu powders increases with increasing the bonding temperature （time）, but get maxima at bonding temperature 600℃ （time 90 min）.

关键词： Reactive diffusion bonding Insert powder layer SiCp/Al metal matrix composites

Distribution of Nb atom in the TiAl+Nb system

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Rare Metals 2001年第1期20卷 5-12页

作者： Xiaodong Ni, Xidong Hui, Guoliang Chen (Applied science School, university of science and technology beijing, beijing 100083. china State Key Laboratory for Advanced Metals and materials, university of science and technology beijing, china) Appl. Sci. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

Based on MEAM (the modified embedded atom method) potential and an average atom model similar to B-W (Bragg-Williams) method, the distribution of Nb atoms in TiAl+Nb compounds with various composition was calculated. The calculation results showed that Nb atoms prefer to occupy the Ti sublattice of L10 structure for all compounds in question. With increasing atomic fraction of Nb and Al, Nb atoms exhibited a trend of ordered distribution on the Ti sublattice and result in a new L10 derivative superlattice structure.

关键词： Computer simulation Intermetallics Superlattices Ternary systems

Flotation Separating Rutile from Calcium and Silicon Gangue Minerals

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Rare Metals 2001年第4期20卷 205-208页

作者： Hao Ding1, HaiLin 2 1) beijing Academy of Building materials, beijing 100041, china 2) university of science and technology beijing, beijing 100083. china 北京建筑材料研究院北京 100041 北京科技大学北京 100083

Rutile separation from calcite, apatite and quartz by flotation was investigated. The results show that the rutile separation from calcium and silicon gangue minerals can be realized with alkyl-imino-bismethylene phos... 详细信息

关键词： rutile calcium and silicon gangue minerals flotation separate alkyl-imino-bismethylene phosphoric acid sodium hexametaphosphate

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

Optimum Design of Movable Screen Jig Cycle

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International Journal of Minerals,Metallurgy and materials 1999年第4期13卷 246-249页

作者： Chunbao Sun Yubo Sun(1 Resources engineering School, university of science and technology beijing, beijing 100083. china2 Department of Mineral engineering, Northeastern university. Shenyang 10006. china) Resources engineering School University of Science and Technology Beijing Beijing 100083 China Department of Mineral engineering Northeastern University Shenyang 110006 China

The basic method for designing and calculating reasonable jig cycle of movable screen jig was presented. The reasonabilityand reliability of designed jig cycle were verified by' means of the test on artificial mixed materials. An iron ore (12-100 mm) was treatedin tile TJD-75 model movable screen jig with the jig cycle. The good results were achieved. This would provide a reliable basis for designof commercial movable-screen jig.

关键词： movable-screen jig jig cycle optimum design

Fractal Structure of the Core Loss Spectrum of Co-based Amorphous Soft Magnetic Alloy with Constant Permeability

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International Journal of Minerals,Metallurgy and materials 1999年第1期13卷 54-56页

作者： Yiping Chen (Applied science School, university of science and technology beijing, beijing 100083. china) Applied science School University of Science and Technology Beijing Beijing 100083 China

In order to check the traditional core loss formula, the core loss spectrum P(f) of Co-based amorphous soft magnetic alloy with constant permeability has been studied. It is found that within a high frequency range from 10 kHz to 200 kHz and at Bm = 0. 1 T,the P(f) has the fractal structure P (f) = Po, and with the increasing of induced anisotropy energy Ku, the fractal dimension Dfrises, thus the total power loss at high frequency increases and the frequency characteristic of P(f) becomes worse.

关键词： amorphous soft magnetic alloy constant permeability core loss fractal

Preparation and characterization of nano-crystalline diamond films on glass substrate

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Journal of university of science and technology beijing 2004年第3期11卷 216-220页

作者： Fanxiu Lu Wubao Yang Zhilin Liu Weizhong Tang Yumei Tong 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

Adherent nano diamond films were successfully deposited on glass substrate bymicrowave plasma assisted CVD method in H_2-CH_4 and Ar-CH_4 environment. Raman, AFM (Atomic ForceMicroscope), TEM (Transmission Electron Microscope), FTIR, and Nano Indentation techniques were usedfor characterization of the obtained nano diamond films. It was found that the average grain sizewas less than 100 nm with a surface roughness value as low as 2 nm. The nano diamond films werefound to have excellent transparency in visible and IR spectrum range, and were as hard as naturaldiamond. Experimental results were presented. Mechanisms for nano diamond film deposition werediscussed.

关键词： nano diamond films microwave plasma assisted CVD characterization glasssubstrate

Surface hardening of Fe-based alloy powders by Nd:YAG laser cladding followed by electrospark deposition with WC-Co cemented carbide

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Rare Metals 2010年第4期29卷 380-384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 Beijing China

This paper presents the results of a study concerned with the surface hardening of Fe-based alloys and WC-8Co cemented carbide by inte- grating laser cladding and the electrospark deposition processes. Specimens of low carbon steel were processed firstly by laser cladding with Fe-based alloy powders and then by electrospark deposition with WC-SCo cemented carbide. It is shown that, for these two treatments, the electrospark coating possesses finer microstructure than the laser coating, and the thickness and surface hardness of the electrospark coating can be substantially increased.

关键词： laser cladding electrospark deposition surface hardening Fe-based alloy cemented carbide

INFLUENCE OF ASSOCIATED AND SEPARATE PRECIPITATION OF γ″ AND γ′ ON STRUCTURE STABILITY IN INCONEL718 AND MODIFIED ALLOYS

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Acta Metallurgica Sinica(English Letters) 1993年第6期6卷 410-414页

作者： DONG jianxin XIE Xishan ZHANG Shouhua university of science and technology beijing,beijing,china doctorate student,Department of materials science and engineering,university of science and technology beijing,beijing 100083.china Univ of science and technology Beijing Beijing China

The precipitation behavior in Inconel 718 and modified alloys has been studied by means of *** structure of associated precipitation and compact morphology of γ″+γ′ were ob- tained by modifying the contents of Al,Ti and *** results show that the com- pact morphology of γ″+γ′ has the best structure stability at higher *** of the transformation γ″→δ in alloy 718 the dissolution of strengthening phases in modified alloy leads material degradation.

关键词： superalloy structure stability associated precipitation compact morphology Inconel 718