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Superplasticity of a SiCw/Zn-22Al Composites

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Journal of Materials Science & Technology 2004年第2期20卷 172-174页

作者： Xiaojing XU, Wei WANG and Lan CAIsch.ol of mech.nical eng.neering, Jiangsu University, Zhenjiang 212013, China sch. of mech. eng. Jiangsu Univ. Zhenjiang 212013 China

In this paper, the superplastic characteristics of a 15 SiC(vol. pct) whisker reinforced Zn-22AI alloy composites, fabricated by low pressure infiltration and solute treatment after extrusion with the extrusion rate of 10:1, was investigated. The result showed that the composite exhibited a tensile elongation of 150% and a strain rate sensitivity value of about 0.33 at the initial strain rate of 6.67×10-2 s-1 and at 658 K where an appropriate amount of liquid phase was presented in the composite.

关键词： Superplasticity SiCw/Zn-22Al matrix composite Liquid phase

THE INVESTIGATION ON THE RHEOLOGICAL BEHAVIOR OF SEMI-SOLID ALUMINUM ALLOY DURING DIE CASTING

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Acta Metallurgica Sinica(eng.ish Letters) 2002年第6期15卷 511-516页

作者： X.J. Yang and J.Liu sch.ol of mech.nic & Electronic eng.neering, Nanchang University, Jiangxi 330029, China sch.ol of mech.nic & Electronic eng.neering, Shanghai University, Shanghai 200072, China sch. of mech. and Electron. eng. Nanchang Univ. Nanchang 330029 China sch. of mech. and Electron. eng. Shanghai Univ. Shanghai 200072 China

Under the condition of die casting and reheating temperature of 570-580 degC, the rheological behavior of semi-solid aluminum alloy (A356) is pseudoplasticity at the shearrate of 2X10^-1X10^4s^(-1), and also shows dil... 详细信息

关键词： shear rate apparent viscosity viscosity model thixocasting

Improvement on strip flatness of cold temper mills by modifying roll contour shape

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Journal of University of Science and Technology Beijing 2004年第3期11卷 251-255页

作者： Xiaoyan Li Jie Zhang Xianlin Chen Jianguo Cao Haixia Li mech.nical eng.neering sch.ol, University of Science and Technology Beijing, Beijing 100083, China mech. eng. sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

A study on roll gap profile (strip profile) control was accomplished in a1700 mm single-stand temper mill. Some critical problems such as the deviation of work roll contourcaused by grinding and wear, the effectiveness of work roll bending were discussed. Using a finiteelement model, the effects of roll contours (ground and wear) on strip profile were *** roll bending effect on strip thickness was also analyzed. It is pointed out that there are somespecial features of flatness control in the temper mill: during temper rolling, roll deformation isslight due to small rolling load, and the loaded roll gap profile mainly depends on work rollcontour, while the backup roll has a little effect on gap crown; the effect of bending force ongauge can not be ignored due to the coupling between flatness control and gauge control. A new rollcontour arrangement adaptable to the mill was presented and has been put into practical *** application of the new set of rolls showed some good results: larger crown control range of workroll bender, higher rolling stability, better strip profile and flatness quality.

关键词： cold rolling temper mill strip shape control roll contour arrangement bending

Numerical Analysis of Hydroforming Deep Drawing of Conical Cup

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Journal of Materials Science & Technology 2001年第1期17卷 131-132页

作者： Yongming KONG Xianbin ZHOU and Min LI Research Center of Sheet Metal Forming, sch.ol of mech.nical eng.neering & Automation, Beijing University of Aeronautics & Astronautics, Beijing 100083, China sch. of mech. eng. Beijing Univ. of Aeron. and Astron. Beijing 100083 China

Aided by the FE-code. analysis is carried to find the proper hydroforming deep-drawing condition for the perfect forming of a conical cup that can not be drawn successfully by conventional deep drawing method. Hydraulic counter pressure must be reasonably controlled, otherwise defects such as fracture and wrinkling can not be avoided. Therefore, the forming procedure is divided into three stages, and the counter pressure is adjusted intentionally to make the blank clamped onto the punch at a suitable time, then deformation at dangerous area is resisted by the effect of the counter pressure and the conical cup can be formed without defects.

关键词： Numerical Analysis of Hydroforming Deep Drawing of Conical Cup Figure

Three-Dimensional Rigid-Plastic FEM Simulation of Bulk Forming Processes with New Contact and Remeshing Techniques

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Journal of Materials Science & Technology 2001年第3期17卷 329-332页

作者： Debin Shan and Youngsuk Kim sch.ol of mech.nical eng.neering, Kyungpook National University, Taegu 702-70 1, South Korea Hyunsoo Kim graduate sch.ol of mech.nical eng.neering, Kyungpook National University, Taegu 702-701, South Korea E-mail: shandb@public sch. of mech. eng. Kyungpook Natl. Univ. Taegu 702-701 South Korea

Some techniques such as die surface description, contact judgement algorithm and remeshing are proposed to improve the robustness of the numerical solution. Based on these techniques, a three-dimensional rigid-plastic FEM code has been developed. Isothermal forging process of a cylindrical housing has been simulated. The simulation results show that the given techniques and the FEM code are reasonable and feasible for three-dimensional bulk forming processes.

关键词： Three-Dimensional Rigid-Plastic FEM Simulation of Bulk Forming Processes with New Contact and Remeshing Techniques FEM Simulation

Metal deformation in skew rolling step-shaft

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Journal of University of Science and Technology Beijing 2003年第5期10卷 59-63页

作者： Yongqiang Kang, Jinping Liu, Cuiping Yang, and Zheng.uan Humech.nical eng.neering sch.ol, University of Science and Technology Beijing, Beijing 100083, China mech. eng. sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The process of rolling step-shaft was simulated with the help of the FEM(Finite-Element Model) software-DEFORM^(TM) 3D. The characteristics of metal flow in differentperiods were analyzed, and the curve of variety in non-round area at different cross-sections of therolled piece, the curve of variety in bulge volume and the curve of variety in non-column volumewere obtained. On this base the method of tool design is worked out and validated by experiment.

关键词： skew rolling FEM metal deformation non-column volume bulge volume

Effect of Rare Earths-Treated Glass Fiber on Impact Wear-Resistance of Metal-Plastic Multilayer Composites

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Journal of Rare Earths 2002年第4期20卷 282-286页

作者：程先华薛玉君谢超英 sch. of mech. eng. Shanghai Jiaotong Univ. Shanghai 200030 China sch. of Mat. Sci. and eng. Shanghai Jiaotong Univ. Shanghai 200030 China

The friction and wear properties under impact load and dry friction conditions of metal-plastic multilayer composites filled with glass fiber, treated with rare earth elements, were investigated. The worn surfaces were observed and analyzed by scanning electron microscopy (SEM). It shows that applying rare earth elements surface modifier to treat the glass fiber surface can enhance the interfacial adhesion between the glass fiber and polytetrafluoroethylene (PTFE), as well as promote the interface properties of the composites. This helps to form a uniformly distributed and high adhesive transfer film on the counterface and abate the friction between the composite and the counterface. As a result, the wear of composite is greatly reduced. The composite exhibits excellent friction properties and impact wear-resistance.

关键词： rare earths metal-plastic multilayer composites friction properties impact wear-resistance

Improved AAG based recognization of machining feature

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Journal of Harbin Institute of Technology(New Series) 2002年第2期9卷 180-187页

作者：顾琳张广玉杨乐民刘文剑 sch. of mech. eng. Harbin Inst. of Technol. Harbin 150001 China

The lost information caused by feature interaction is restored by using auxiliary faces (AF) and virtual links (VL). The delta volume of the interacted features represented by concave attachable connected graph (CACG) can be decomposed into several isolated features represented by complete concave adjacency graph (CCAG). We can recognize the feature’s sketchy type by using CCAG as a hint; the exact type of the feature can be attained by deleting the auxiliary faces from the isolated feature. United machining feature (UMF) is used to represent the features that can be machined in the same machining process. It is important to the rationalizing of the process plans and reduce the time costing in machining. An example is given to demonstrate the effectiveness of this method.

关键词： machining feature feature recognition feature interaction graph matching auxiliary face virtual link united machining feature intermediate information cell

Research on Modeling and Reusing of Computer Numerical Control Software with Object-oriented Technology

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Journal of Donghua University(eng.ish Edition) 2001年第3期18卷 66-69页

作者：胡俊王宇晗王涛蔡建国 sch. of mech. eng. Shanghai Jiaotong Univ. Shanghai 200030 China

To improve the reusable and configurable ability of computer numerical control ( CNC ) software, a new method to construct reusable model of CNC software with object-oriented (OO) technology is proposed. Based on analyzing function of CNC software, the article presents how to construct a general class library of CNC software with OO technology. Most function modules of CNC software can he reused because of inheritable capability of classes. Besides, the article analyzes the object relational model in request/report mode, and multitask concurrent management model, which can he applied on double-CPU hardware platform and Windows 95/NT environment. Finally, the method has been successfully applied on a turning CNC system and a milling CNC system, and some function modules have been reused.

关键词： CNC Software, Object- Oriented, Request/Report,Multitask Concurrent Process.