检索结果-南通市图书馆

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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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 technology, huazhong university of science and technology,{3., China 2. Institute of laser technology and Engineering, huazhong university of science and technology,{3., China 3. Mechanical Engineering College, Hubei university of technology, wuhan 43.068, China School of Material science and technology Huazhong University of Science and Technology

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.

Effect of Powder Particle Size on the Properties and Microstructure of Ti(C,N)-Based Cermet

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2001年第1期20卷 47-51页

作者： Yong Zheng, Weihao Xiong (key state Laboratory of Die technology,{3., wuhan 43.074, China) 华中科技大学材料成形与模具技术国家重点实验室湖北武汉 430074

The influence of raw powder particle size on the properties and microstructures of Ti (C, N)-based cermets has been studied. The conclusions are as follows: The microstructures of cermets were composed of two kinds of grains, the one with black cores surrounded by obvious rim structures, and the other whose cores were white with unconspicuous rim structures and adhesive phase. In the cermet made from fine powders, the amount of grains with white cores was much more than that in cermet made from coarse powders. In addition, their properties were also much better.

关键词： Ti(C, N)-based cermet powder particle size property microstructure

Modeling and simulation of heat transfer for glass bulb mold

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2005年第7期15卷 650-655页

作者： ZHOU Huamin and LI Dequn (state key Laboratory of Mold & Die technology,{3., wuhan 43.074, China) state key Laboratory of Mold & Die technology Huazhong University of Science and Technology Wuhan 430074 China

Cooling system design in glass bulb pressing operation can greatly affect the productivity and the quality of the final product. The concept of cyclic-averaged steady temperature field is proposed in modeling. Heat transfer in the mold region is considered to be a cyclic-steady, three-dimensional conduction; heat transfer within the glass melt region is treated as a transient, one-dimensional conduction; heat exchange between the cooling system surface and coolant is treated as a steady heat convection. A hybrid model consisting of a three-dimensional boundary element method for the mold region and a finite-difference method with a variable mesh for the melt region is used for numerical simulation. Compared with the experimental data, the numerical model developed here is computationally efficient and sufficiently accurate.

关键词： glass bulb mold numerical simulation boundary element method cyclic-averaged steady temperature field.

Preparation of Oriented Barium Titanate Thin Films by Combination of Electrophoretic Deposition with Hydrothermal Treatment

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials science & technology 2010年第11期26卷 996-1000页

作者： Lihong Xue and Youwei Yan state key Laboratory of Materials Processing and Die and Mould technology,{3. {3. of science and technology,wuhan 43.074,China state key Laboratory of Materials Processing and Die and Mould technology Huazhong University of Science and Technology Wuhan 430074 China

Highly oriented barium titanate （BaTiO 3. thin films on Pt substrate were fabricated by combination of electrophoretic deposition with hydrothermal *** structure and morphology of thin films were characterized by X-ray diffraction and field-emission scanning electron *** is found that the titania precursor film,Ba（OH）2 concentration and hydrothermal temperature play crucial roles in the film morphology and *** BaTiO3.thin films with highly （110） preferred orientation can be formed on polycrystalline Pt substrate by appropriate adjustment of the reaction *** orientation parameter f of highly oriented BaTiO3.films was up to *** films exhibited a smooth and crack-free surface and remained in the layered *** situ topotactic transformation and dissolution-crystallization mechanisms were proposed to explain the morphology and orientation of BaTiO3.films during hydrothermal treatment.

关键词： Barium titanate Preferred orientation Electrophoretic deposition Hydrothermal treatment

Removal of elemental mercury by iodine-modified rice husk ash sorbents

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2010年第10期22卷 1629-1636页

作者： Pengfei Zhao,Xin Guoff,Chuguang Zheng state key Laboratory of Coal Combustion,huazhong {3. of {3. and technology,wuhan 43.074,China state key Laboratory of Coal Combustion Huazhong University of Science and Technology

Iodine-modified calcium-based rice husk ash sorbents （I2/CaO/RHA） were synthesized and characterized by X-ray diffraction, X-ray fluorescence, and N2 isotherm adsorption/desorption. Adsorption experiments of vapor-phase elemental mercury （Hg^0） were performed in a laboratory-scale fixed-bed reactor. I2/CaO/RHA performances on Hg^0 adsorption were compared with those of modified Cabased fly ash sorbents （I2/CaO/FA） and modified fly ash sorbents （I2/FA）. Effects of oxidant loading, supports, pore size distribution, iodine impregnation modes, and temperature were investigated as well to understand the mechanism in capturing Hg^0. The modified sorbents exhibited reasonable efficiency for Hg^0 removal under simulated flue gas. The surface area, pore size distribution, and iodine impregnation modes of the sorbents did not produce a strong effect on Hg^0 capture efficiency, while fair correlation was observed between Hg^0 uptake capacity and iodine concentration. Therefore, the content of 12 impregnated on the sorbents was identified as the most important factor influencing the capacity of these sorbents for Hg^0 uptake. Increasing temperature in the range of 80-140℃ caused a rise in Hg^0 removal. A reaction mechanism that may explain the experimental results was presumed based on the characterizations and adsorption study.

关键词： mercury sorbents fly ash rice husk ash iodine impregnation

Flame-retardant Mechanism of Magnesium Oxychloride in Epoxy Resin

在线全文

学校读者我要写书评

暂无评论

Journal of wuhan university of technology(Materials{3.) 2009年第1期24卷 127-131页

作者：秦麟卿 state key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology Center for Material Research and Analysis Wuhan University of Technology

Flame-retardant mechanism of magnesium oxychloride （M OC） in EP was in-vestigated by limiting oxygen index （LOI）, XRD, SEM, TG-DTG and DSC. The results show that MOC performed well as an inorganic flame-retardant in EP. When the content of MOC is 50%, the LOI of EP reaches 29.6% and mass of residual char reaches 9.6%. The flame retarde mechanism of MOC is due to the synergies of diluting, cooling, catalyzing char forming and obstructing effects.

关键词： magnesium oxychloride epoxy resin flame-retardant properties flame retardedmechanism

HCWCI/Carbon Steel Bimetal Liner by Liquid-Liquid Compound Lost Foam Casting

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第10期19卷 13-19页

作者： XIAO Xiao-feng1,2, YE Sheng-ping2, YIN Wei-xin3. XUE Qiong4 (1. School of Mechanical Engineering and Automation, wuhan Textile university, wuhan 43.073. Hubei, China 2.{3. key Laboratory of Material Processing and Die and Mould technology, huazhong university of science and technology, wuhan 43.074, Hubei, China 3. wuhan Zhike Abrasive-Resistant Material science and technology Development Co Ltd, wuhan 43.073. Hubei, China 4. College of science, wuhan university of technology, wuhan 43.079, Hubei, China) School of Mechanical Engineering and Automation Wuhan Textile University Wuhan Hubei China state key Laboratory of Material Processing and Die and Mould technology Huazhong University of Science and Technology Wuhan Hubei China wuhan Zhike Abrasive-Resistant Material science and technology Development Co Ltd Wuhan Hubei China College of science Wuhan University of Technology Wuhan Hubei China

Impact, friction and corrosion from the grinding balls and the grinding medium during the mineral processing result in liner breakage. Liner, made from Hadfield steel or alloyed steel, could not have served in wet grinding environment for more than ten months. Composite liner, made from HCWCI (high Cr white cast iron) and carbon steel, has been developed successfully with liquid-liquid composing process based on LFC (lost foam casting). The microstructure of composite was analyzed with optical microscope, SEM (scanning electron microscope)/EDX energy-dispersive X-ray and XRD (X-ray diffraction). According to micrograph, the combination region of two metals was staggered like dogtooth, no mixtures occurred between two liquid metals, and its interface presented excellent metallurgical bonding state. The results of mechanical property test show that, the hardness of HRC, the fracture toughness, and the bending strength are more than 61, 16.5 J/cm2 and 1 600 MPa, respectively. Comparison between liners made from bimetal composite and alloyed steel has also been investigated in industrial hematite ball mill. The results of eight months test in wet grinding environment prove that the service life of bimetal composite liner is three times as long as that of one made from alloyed steel.

关键词： composite liner bimetal liquid-liquid compound composite interface lost foam casting high Cr white cast iron

Numerical simulation of the transient multiphase field during plasma deposition manufacturing composite materials

在线全文

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2009年第4期52卷 508-517页

作者： KONG FanRong1,2,ZHANG HaiOu1 & WANG GuiLan3.1 state key Laboratory of Digital Manufacturing Equipment and technology,{3. {3. of science and technology,wuhan 43.074,China 2 Research Center for Advanced Manufacturing,Southern Methodist {3.,3.01 Dyer Street,Dallas,Texas 75205,USA 3.College of Material science and Engineering,{3. {3. of science and technology,wuhan 43.074,China state key Laboratory of Digital Manufacturing Equipment and technology Huazhong University of Science and Technology Wuhan China Research Center for Advanced Manufacturing Southern Methodist University Dallas USA College of Material science and Engineering Huazhong University of Science and Technology Wuhan China

A solid/liquid/gas unified model has been developed to investigate the gradient composition formation during the plasma deposition manufacturing(PDM) composite materials process. In this model,an enthalpy porosity model was applied to deal with the melting and solidification of the deposited layer,and a level-set approach was introduced to track the evolution of the free surface of the molten pool and the deposited layer. Moreover,complicated physical phenomena occurring at the liquid/gas interface,including forced convection heat loss,heat emission and plasma heat source,have been incorporated into the governing equations by source terms. In this study,the numerical experiment of nickel base alloy powder deposited on the medium steel substrate by PDM technique was implemented based on the staggered grid and SIMPLEC algorithm. Concentration gradient distribution of the solute material at the composite material interface,fluid flow and temperature distribution in the molten pool and the deposited layer have been investigated in detail.

关键词： plasma deposition manufacturing composite material solid/liquid/gas unified model level-set approach

Modeling and simulation of residual stresses during glass bulb pressing process

在线全文

学校读者我要写书评

暂无评论

science China(Technological sciences) 2007年第1期50卷 103-117页

作者： ZHOU HuaMin, XI GuoDong & LI DeQun state key Laboratory of Plastic Forming Simulation and Mold & Die technology,{3., wuhan 43.074 state key Laboratory of Plastic Forming Simulation and Mold & Die technology Huazhong University of Science and Technology

The residual stresses accumulated in the forming process have great effects on the product quality of the glass bulb. Based on the characteristics analysis of glass bulb forming, a mathematical model has been established for calculating residual stresses of glass pressing process. The material is assumed as thermorheologically simple thermoviscoelastic material, and the flow-induced stress is neglected. The consequences of equilibrium and compatibility equations are discussed in detail, and the boundary conditions are specified for various stages of the forming process. The numerical solution is based on the theory of thin layers, combined with finite difference method in the time and layer difference in the thickness direction. The presented model and solution method could easily be extended to general pressing process of glass, and applied to problems relative to glass pressing, providing extensive reference values. keywords glass bulb - residual stresses - mathematical modeling - numerical simulation - theory of thin layers Supported by the National Natural science Foundation of China (Grant No. 50205011), and the Program for New Century Excellent Talents in university (Grant No. NCET-04-0718)

关键词： glass bulb residual stresses mathematical modeling numerical simulation theory of thin layers