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Mold-filling ability of semisolid alloy

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Journal of University of Science and Technology Beijing 2002年第4期9卷 253-257页

作者： ShumingXing LizhongZhang dabenzeng JuntaoShi Departmentofmechanicalengineering NorthernJiaotongUniversityBeijing100044China Departmentofmechanicalengineering TsinghuaUniversityBeiiing100084.China

The mold-filling ability of the semisolid alloy has very important effects onthe quality and properties of the work pieces produced by the semisolid forming process. Thefactorial experiments show that all of the heating factors, such as mold temperature, heatingtemperature and the keeping time of billets, have some effects on the mold-filling ability ofsemisolid alloy. According to the analysis of influencing extent on the filling ability, it is foundthat the most important one of the factors is the mold temperature instead of the billetstemperature, the next one is the heating temperature of the billet, and the keeping time rows on thethird. It is also found that there is an interrelation between the billet heating temperature andthe mold temperature. The effect of the interrelation on the mold-filling ability is even strongerthan the keeping time. The higher the mold temperature, heating temperature or the keeping time is,the better the mold-filling ability of the semisolid alloy is. The parameter to describe themold-filling ability, defined as the maximum filling height along the uptight direction or themaximum filling length along the horizontal direction, can be theoretically determined according tothe flowing theory of viscous fluid.

关键词： semisolid alloy semisolid processing mold-filling ability aluminumalloy

Semi-solid Pressing Bonding Strength between Steel and Cu-graphite Composite

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Journal of Materials Science & Technology 2005年第2期21卷 265-268页

作者： PengZHANG YunhuiDU HanwuLIU dabenzeng JianzhongCUI LiminBA DepartmentofMechanicalEngineering NorthernJiaotongUniversityBeijing100044China DepartmentofMechanicalEngineering TsinghuaUniversityBeijing100084China DepartmentofMetalForming NortheastenUniversityShenyang110004China AnshanAutomobileFittingsFactory Anshan114014China

The pressing bonding of steel plate with QTi3.5-3.5graphite slurry was studied. The relationship among preheating temperature of steel plate, preheating temperature of dies, solid fraction of QTi3.5-3.5graphite slurry, and interfacial shear strength of bonding plate could be established with artificial neural networks perfectly. This model could be optimized with a genetic algorithm. The results show that the optimum bonding parameters are: 618℃ for preheating temperature of steel plate, 526℃ for preheating temperature of dies and 46.2% for solid fraction of QTi3.5-3.5graphite slurry, and the largest interfacial shear strength of bonding plate is 128.3 MPa.

关键词： Steel-mushy QTi3.5-3.5graphite bonding Artificial neural networks Genetic algorithm

Interfacial mechanical property of steel-mushy Al-20Sn bonding

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Journal of University of Science and Technology Beijing 2004年第2期11卷 165-168页

作者： PengZhang YunhuiDu HanwuLiu dabenzeng JianzhongCui LiminBat DepartmentofMechanicalEngineering BeijingJiaotongUniversityBeijing100044China DepartmentofMechanicalEngineering TsinghuaUniversityBeijing100084China MetalFormingDepartment NortheasternUniversityShenyang110006China AnshanAutomobileFittingsFactory Anshan114014China

The bonding of a steel plate to Al-20Sn slurry was conducted using thecasting rolling technique. The surface of the steel plate was defatted, descaled, immersed (inK_2ZrF_6 flux aqueous solution) and stoved. Al-20Sn slurry was prepared using the electromagneticmechanical starring method. The interfacial mechanical property of the bonding plate was researchedto determine the relationship between the diffusion time and the interfacial shear strength. Inorder to identify the mechanism of bonding, the interfacial structure of the bonding plate wasstudied. The results show that at a prebeat temperature of the steel plate of 505 deg C and a solidfraction of Al-20Sn slurry of 35 percent, the relationship between the interfacial shear strength Sand the diffusion time t is S=28.8+4.3t-0.134t^2 +0.0011t^3. When the diffusion time is 22 s, thelargest interfacial shear strength is 70.3 MPa, and the corresponding interface is a new one whichis made up of Fe-Al compound and Fe-Al solid solution alternatively and in a right proportion. Inthis interfacial structure, the interfacial embrittlement does not happen and Fe-Al compound canplay its role in strong combination adequately.

关键词： interfacial shear strength diffusion time interfacial structure

Influence of Solid Fraction on Structure of QTi3.5-15/Graghite Slurry

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Journal of Materials Science & Technology 2004年第6期20卷 794-796页

作者： PengZHANG YunhuiDU HanwuLIU dabenzeng dianzhongCUI LiminBA DepartmentofMechanicalEngineering BeijingJiaotongUniversityBeijing100044China DepartmentofMechanicalEngineering TsinghuaUniversityBeijing100084China MetalFormingDepartment NortheasternUniversityShenyang110006China AnshanAutomobileFittingsFactory Anshan114014China

The electromagnetic-mechanical stirring technology was used to prepare QTi3.5-15/graghite slurry. The distribution of graphite particies in QTi3.5-15/graghite slurry was studied using cold quenching method. The results show that solid fraction of QTi3.5-15/graphite slurry increases with the decreasing of stirring temperature. There is a linear relationship between solid fraction and stirring temperature. With the increasing of solid fraction, the distribution of graphite particies in slurry becomes uniform gradually. When the solid fraction is larger than 45%, the rising of graphite particies in slurry can be restricted, and QTi3.5-15/graghite slurry with uniform distribution of graphite particies can be prepared.

关键词： Copper alloy Electromagnetic stirring Composite Graphite particles

Study on Mechanical Property in Steel-Aluminum Solid to Liquid Bonding

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Journal of Materials Science & Technology 2003年第2期19卷 149-151页

作者： LizhongZHANC PengZHANG YunhuiDU dabenzeng JianzhongCUI LiminBA DepartmentofMechanicalEngineering NorthernJiaotongUniversityBeijing100044China DepartmentofMechanicalEngineering TsinghuaUniversityBeijing100084China MetalFormingDepartment NortheastenUniversityShenyang110004China AnshanAutomobileFittingsFactory Anshan114014China

The bonding of solid steel plate to liquid Al was conducted using rapid solidification. The influence of thickness of Fe-Al compound layer at the interface on interfacial shear strength of bonding plate was studied. The results show that the relationship between thickness of Fe-AI compound layer and interfacial shear strength is 5=30.4+8.51 h-0.51 h2 +0.007 h3 (where h is thickness of Fe-AI compound layer, S is interfacial shear strength). When thickness of Fe-AI compound layer is 10.7 um, the largest interfacial shear strength is 71.6 MPa.

关键词： Mechanical property Rapid solidification Interface Interfacial shear strength

Influence of Rolling Treatment on Interfacial Shear Strength of Steel-mushy Al-7graphite Bonding Plate

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Journal of Materials Science & Technology 2004年第6期20卷 694-696页

作者： PengZHANG YunhuiDU HanwuLIU dabenzeng JianzhongCUI LiminBA DepartmentofMechanicalEngineering BeijingJiaotongUniversityBeijing100044China DepartmentofMechanicalEngineering TsinghuaUniversityBeijing100084China MetalFormingDepartment NortheastenUniversityShenyang110006China AnshanAutomobileFittingsFactory Anshan114014China

At room temperature, the rolling treatment of steel-mushy Al-7graphite bonding plate was carried out under different relative reduction. The influence of rolling on interfacial mechanical property of this bonding plate was studied. The results show that, for steel-mushy Al-7graphite bonding plate which is made up of 1.2 mm in thickness 08AI steel plate and 2.0 mm in thickness Al-7graphite layer, there is a nonlinear relationship between interfacial shear strength of bonding plate and relative reduction of rolling. When relative reduction of rolling is smaller than 2.59%, with the increasing of relative reduction, interfacial shear strength of bonding plate increases gradually. When relative reduction of rolling is bigger than 2.59%, with the increasing of relative reduction, interfacial shear strength of bonding plate decreases continuously. When relative reduction of rolling is 2.59%, the largest interfacial shear strength 77.0 MPa can be obtained.

关键词： Rolling treatment Relative reduction Interfacial shear strength

Interfacial Structure of Steel-Mushy Al-20Sn Bonding Plate

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Journal of Materials Science & Technology 2004年第2期20卷 193-195页

作者： PengZHANG YunhuiDU HanwuLIU dabenzeng JianzhongCUI LiminBA DepartmentofMechanicalEngineering BeijingJiaotongUniversityBeijing100044China DepartmentofMechanicalEngineering TsinghuaUniversityBeijing100084China MetalFormingDepartment NortheasternUniversityShenyang110006China AnshanAutomobileFittingsFactory Anshan114014China

Fe-AI compound at the interface of steel-mushy AI-20Sn bonding plate was studied quantitatively. The relationship between ratio of Fe-AI compound at interface and bonding parameters (such as preheat temperature of steel plate, solid fraction of AI-20Sn slurry and rolling speed) was established by artificial neural networks perfectly. The results show that when the bonding parameters are 505℃ for preheat temperature of steel plate, 34.3% for solid fraction of AI-20Sn slurry and 10 mm/s for rolling speed, the reasonable ratio of Fe-AI compound corresponding to the largest interfacial shear strength of bonding plate is obtained. Its value is 72%. This reasonable ratio of Fe-AI compound is a quantitative criterion of interfacial embrittlement, that is, when the ratio of Fe-AI compound at interface is larger than 72%, interfacial embrittlement will occur.

关键词： Interfacial structure Fe-Al compound Artificial neural networks

Thickness of compound layer in steel-aluminum solid to liquid bonding

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Journal of University of Science and Technology Beijing 2003年第5期10卷 48-52页

作者： PengZhang YunhuiDu HanwuLiu ShumingXing dabenzeng JianzhongCui LiminBa DepartmentofMechanicalEngineering NorthernJiaotongUniversityBeijing100044China DepartmentofMechanicalEngineering TsinghuaUniversityBeijing100084China MetalFormingDepartment NortheasternUniversityShenyang110006China AnshanAutomobileFittingsFactory.Anshan114014 China

The bonding of solid steel plate to liquid aluminum was studied using rapidsolidification. The surface of solid steel plate was defatted, descaled, immersed (in K_2ZrF_6 fluxaqueous solution) and stoved. In order to determine the thickness of Fe-Al compound layer at theinterface of steel-aluminum solid to liquid bonding under rapid solidification, the interface ofbonding plate was investigated by SEM (Scanning Electron Microscope) experiment. The relationshipbetween bonding parameters (such as preheat temperature of steel plate, temperature of aluminumliquid and bonding time) and thickness of Fe-Al compound layer at the interface was established byartificial neural networks (ANN) perfectly. The maximum of relative error between the output and thedesired output of the ANN is only 5.4%. From the bonding parameters for the largest interfacialshear strength of bonding plate (226℃ for preheat temperature of steel plate, 723℃ for temperatureof aluminum liquid and 15.8 s for bonding time), the reasonable thickness of Fe-Al compound layer10.8 μm was got.

关键词： bonding of steel plate to liquid aluminum rapid solidification thickness ofFe-Al compound layer artificial neural networks

Influence of Diffusion Time on Steel-Aluminum Solid to Liquid Bonding Interfacial Structure

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Journal of Materials Science & Technology 2002年第5期18卷 468-470页

作者： PengZHANG Yunhui ShumingXING LizhongZHANG dabenzeng Jianzhong LiminBA Dept. of Mech. Eng. Northern Jiaotong Univ. Beijing 100044 China Dept. of Mech. Eng. Tsinghua Univ. Beijing 100084 China Metal Forming Dept. Northeastern Univ. Shenyang 110004 China Anshan Automobile Fittings Factory Anshan 114014 China

The bonding of steel plate to aluminum liquid was conducted using rapid solidification. The influence of diffusion time on interfacial structure was studied. The results showed that under the condition of 750癈 for the temperature of aluminum liquid and 200癈 for the preheat temperature of steel plate, when diffusion time was shorter than 4.3 s, there was only Fe-AI solid solution at the interface. When diffusion time was longer than 4.3 s, Fe-AI compound began to form at the interface. The relationships between diffusion time t and thickness of Fe-AI compound layer H are H=-9.72+2.62t-0.08t2 (4.3 s15 s).

关键词： Diffusion Rapid solidification Interfacial structure.