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The mathematical model of wetting angle of heterogeneous nucleation

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science china(Technological sciences) 2004年第4期47卷 391-397页

作者： HUANG Cheng1, SONG Bo1, MAO jinghong2 & ZHAO Pei3.1. school of metallurgical and Ecological engineering, {3. of science and technology Beijing, Beijing 100083. china 2. school of Material science, {3. of science and technology Beijing, Beijing 100083. china 3. Central Iron and Steel Research Institute, Beijing 100081, china 1. school of metallurgical and Ecological engineering University of Science and Technology Beijing 100083 Beijing China 2. school of Material science University of Science and Technology Beijing 100083 Beijing China 3. Central Iron and Steel Research Institute 100081 Beijing China

The heterogeneous nucleation has been analyzed in terms of the thermodynamic theory, and the mathematical model of wetting angle of heterogeneous nucleation has been developed based on the dynamic requirements of hetero- and homogeneous nucleation. With the wetting angel model, the wetting angles of different catalysts in liquid iron have been calculated. The result shows that the wetting angle of most catalysts is smaller than 40, and the value of f() is far less than 1. The wetting angles of TiN, TiC and RE2O3.are smaller, while the wetting angle of MnO is bigger among the ordinary nucleation catalysts. The wetting angles calculated by this model are in agreement with the results of other research work.

关键词： heterogeneous nucleation, mathematical model, wetting angle, undercooling.

Application of the annexation principle to the study of thermodynamic properties of ternary metallic melts In-Pb-Ag and In-Bi-Sb

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Rare Metals 2002年第2期21卷 142-151页

作者： zhang jianmetallurgical engineering {3..university of science and technology Beijing, Beijing 100083. china metallurgical engineering school University of Science and Technology Beijing 北京 100083

Based on the phase diagrams, measured activities an the annexationprinciple, the calculating models of mass action concentrations forin-Pb-Ag and In-Bi-Sb ternary metallic melts have been *** results of calculation both agree with practice, and obey the lawof mass action, showing that the models formulated can reflect thestructural reality of the corresponding melts and the annexationprinciple is applicable to the them.

关键词： activity mass action concnetration th annexation principle In-PB-Ag

The characteristics of arc beam shaping in hybrid plasma and laser deposition manufacturing

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science china(Technological sciences) 2006年第2期49卷 238-247页

作者： zhang Hai’ou1, QIAN Yingping1,3. WANG Guilan1 & ZHENG Qiguang2 1. school of Material science and {3., Huazhong university of science and {3., Wuhan 43.074, china 2. Institute of Laser {3. and engineering, Huazhong university of science and {3., Wuhan 43.074, china 3. Mechanical engineering College, Hubei university of {3., Wuhan 43.068, china 1. school of Material science and technology Huazhong University of Science and Technology Wuhan 430074 China 3. Mechanical engineering College Hubei University of Technology Wuhan 430068 China 2. Institute of Laser technology and engineering Huazhong University of Science and Technology Wuhan 430074 China

As a new direct metal prototyping technology,the hybrid plasma and laser deposition manufacturing (PLDM) is proposed in this paper. In order to figure out the characteristics of plasma arc beam and mould in the PLDM process of high temperature alloy, the high speed CCD camera is used to obtain the picture around the plasma arc. Afterwards the sketch of picture is clearly obtained. And the effect of laser parameter, such as average power, pulse width, pulse repetition frequency and the angle between laser beam and plasma arc beam on the plasma arc appearance, is studied experimentally. The results show that the modality of plasma arc beam is markedly influenced by laser beam. And the improvements of shape precision and surface state of the layer deposited by PLDM are confirmed.

关键词： plasma hybrid laser, direct deposition, plasma arc beam, molding character, high-temperature alloy.

Surface Nanocrystallization of Magnesium Alloy AZ91D by High-Energy Shot Peening

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journal of Wuhan university of technology(Materials science) 2009年第4期24卷 515-519页

作者：张津 school of Materials science & engineering University of Science and Technology Beijing College of Materials science & engineering Chongqing University of Technology

High-energy shot peening （HESP）, a method to produce severe plastic deformation by high velocity flying balls, was applied on die cast magnesium alloy AZ91D. Effects of surface nanocrystallization by HESP and heat treatment at different temperatures were investigated. The mi- crostructure evolution was conducted using X-ray diffraction （XRD） and field emission scanning electronic microscopy （FESEM）. The hardness was measured by microhardness tester. The experimental results show that surface nanocrystrallization of AZ91D obtained by HESP would lead to the increase of microhardness. Low temperature heated at 100℃ for 1 h do not change the property obviously. However, both the microstructure and microhardness vary greatly after heat treatment at 400℃ for 1 h.

关键词： AZ91 D surface nanocrystallization HESP microhardnss corrosion resistance

Thermodynamic properties and mixing thermodynamic parameters of binary homogeneous metallic melts

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Rare Metals 2003年第1期22卷 25-32页

作者： zhang Manmetallurgical engineering {3., university of science and technology Beijing, Beijing 100083. china metallurgical engineering school University of Science and Technology Beijing 北京 100083

After the investigation on the thermodynamic properties and mixingthermodynamic parameters of binary homogeneous metallic melts involving compound, peritectic as wellas solid solution, it was found that the equations of mixing free energy DELTA G^m and excess freeenergy DELTA G^(XS) of them can he expressed by the following equations: DELTA G^m = SIGMA x [SIGMAN_i DELTA G_I^(THETA) + RT(SIGMA N_j ln N_j + SIGMA N_i ln N_i )] and DELTA G^(XS) = DELTA G^m -RT(a ln a + b ln b), respectively.

关键词： metallic melt mixing thermodynamic parameter coexistence theory activity mass action concentration

Analysis for twinning and slip in face-centered cubic crystals under axisymmetric co-deformation

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science china(Technological sciences) 2006年第5期49卷 521-536页

作者： CHEN Zhiyong1,2, CAI Hongnian1, zhang Xinming2, WANG Fuchi1 & TAN Chengwen1,3.1. school of Material science and {3., Beijing Institute of technology, Beijing 100081, china 2. school of Material science and {3., Central South university, Changsha 410083. china 3. school of Material science and {3., Beijing university of Aeronautics and Astronautics, Beijing 100083. china 1. school of Material science and engineering Beijing Institute of Technology Beijing 100081 China 2. school of Material science and engineering Central South University Changsha 410083 China 3. school of Material science and engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

The maximum work principle of Bishop-Hill was developed to analyze the axisymmetric co-deformation in face-centered cubic crystals (f.c.c.) for twinning on {111} 112 and slip on {111} 110 systems. The influence of ξ , the ratio of critical re- solved shear stress for twinning to slip, on the yield stress states and corresponding active slip or/and twinning systems for orientations in the standard stereographic triangle of cubic crystal was investigated systematically. The Taylor factors and the anisotropy of yield strength for three important orientations [100], [110] and [111] in orientation space were analyzed. It is found that the yield strength asymmetry for the case of axisymmetric de- formation of tension and compression can be explained based on the microscopic theory of crystal plasticity. The concept of orientation factor for twinning ability was proposed and the deformation mechanism map in the orientation space was established for the case of axisymmetric deformation. The deformation texture formation and development of f.c.c. crystals with low stacking fault energy for axisymmetric tension can be explained qualita- tively on the basis of analyzed results.

关键词： twinning slip face-centered cubic crystals axisymmetric co-deformation Bishop-Hill maximum work principle yield strength anisotropy

A Fuzzy Model for Evaluating the Mining Condition of Underground Coal Mines

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International journal of Minerals,Metallurgy and Materials 1999年第4期13卷 242-245页

作者： Zhongrue Li Shaowen zhang(Resources engineering school, {3. of science and technology Beijing, Beding 100083. china) Resources engineering school University of Science and Technology Beijing Beijing 100083 China

In mining industries no mines are identical and each mine has its own unique set of mining conditions. In order to study thecondition of mines for efficiency, safety and economy reasons, a fuzzy model is presented based on fuzzy evaluation. Relevant data fromfive mines were collected and the model was used to evaluate the mining condition of these mines. The evaluation results are in conformity with the real situation.

关键词： fuzzy model mining condition coal mine

Chemical Extraction Preparation of Delithiated Cathode Materials of Li-ion Battery

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journal of Wuhan university of technology(Materials science) 2009年第6期24卷 863-866页

作者：闫时建 school of Materials science and engineering Taiyuan University of Science and Technology

A method of conventional chemical reaction to prepare delithiated cathode materials of Li-ion battery was introduced. The cathode material of Li-ion battery was mixed with oxidizing agent Na2S2O8 in water solution, and the solution was stirred continuously to make the chemical reaction proceed sufficiently, then the reaction product was filtered and finally the insoluble delithiated cathode material was obtained. A series of tests were conducted to verify the composition, crystal structure and electrochemical property of the delithiated cathode materials were all desirable. This method overcomes the shortcomings of battery charging preparation and chemical extraction preparation employing other oxidizing agents.

关键词： chemical extraction delithiated cathode material Li-ion battery

Effects of Na/K ratio on the phase structure and electrical properties of Na_xK_(1-x)NbO_3.lead-free piezoelectric ceramics

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Rare Metals 2010年第2期29卷 220-225页

作者： zhang Qian, zhang Boping, Li Haitao, and SHANG Pengpeng school of Materials {3. and engineering, university of {3. and technology Beijing, Beijing 100083. china school of Materials science and engineering University of Science and Technology Beijing

Lead-free piezoelectric NaxK1-xNbO3.x = 0.3.0.8）（NKN） ceramics were fabricated by normal sintering at 1060°C for 2 *** and electrical properties of the ceramics were investigated with a special emphasis on the influence of Na *** grain size of the produced dense ceramic was decreased by increasing Na content.A discontinuous change in the space distance was found at the composition close to Na0.7K0.3.bO3.ceramic, which indicates the presence of a transitional composition between two different orthorhombic phases, which is similar to the behavior of morphotropic phase boundary（MPB） in NaxK1-xNbO3.*** MPB-like behavior contributes to the enhanced piezoelectric coefficient d3. of 122 pC/N, planar-mode electromechanical coupling coefficient kP of 28.6%, and dielectric constant εr of 703. respectively for the Na0.7K0.3.bO3.*** temperature TC and the transitional temperature TO-T from orthorhombic to tetragonal phase are observed at around 420°C and 200°C, respectively.

关键词： lead-free piezoelectric ceramics NKN sintering morphotropic phase boundary(MPB)