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STRENGTHENING CAST IRON MATRIX BY ALLOYINGELEMENTS WITH POSITIVE AND NEGATIVESEGREGATION

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Acta Metallurgica Sinica(English Letters) 1997年第4期10卷 329-332页

作者： Fan, z.K. wang, Y.q. Liang, S.H. Huang, H.S. Xi'an Univ of Technology Xi'an China

The combinational use of alloying elements with positive and negative segregation has been shown to be very effective in strengthening the matrix of cast iron. Negative segregation alloying elements, Cu and Si, make the inner parts of dendritic austenites and eutectic cells get good hardenability. On the contrary, positive segregation alloying elements Cr and Mn make the outer parts of dendrites have higher microhardness. Appropriate combination of the above two types of alloying elements can produce a uniform microhardness and high strength in gray cast irons.

关键词： Cast iron Chromium Copper Hardness Manganese Segregation (metallography) Silicon Strengthening (metal)

Pinless Friction Stir Spot Welding of Mg-3Al-1zn Alloy with zn Interlayer

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Journal of Materials Science & Technology 2016年第1期32卷 76-88页

作者： R.z.Xu D.R.Ni q.Yang C.z.Liu z.Y.Ma College of Materials Science and Engineering Shenyang Aerospace University Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

With the addition of a thin zn interlayer, 2.4 mm thick Mg-3AI-1zn alloy sheets were friction stir spot welded （FSSW） using a pinless tool with fiat, convex and concave shoulder shapes. The results showed that an alloying reaction took place between the Mg substrate and zn interlayer during FSSW, forming a discontinuous intermetallics layer composed of dispersive （α-Mg ＋ Mgzn） eutectic structure under- neath the shoulder and a Mg-zn intermetallics bonding zone at the outside of the joints. This alloying reaction increased the bonded area and eliminated the hook defects, thereby producing sound FSSWjoints with a shallow keyhole without hook defects. The increase of plunge depth was beneficial to the Mg-zn diffusion, thereby increasing the tensile-shear load of the joints. However, excessive plunge depths re- sulted in a decrease of the effective sheet thickness, reducing the strength of the joints. At a small plunge depth, the convex and concave shoulders were more beneficial to the interface reaction than the fiat shoul- der. The maximum joint load of 6.6 kN was achieved by using the concave shoulder at a plunge depth of 1.0 mm. A post-welding heat treatment promoted the dissolution of the discontinuous reaction layer in the joints; however, it led to the occurrence of void defects, influencing the bonding strength.

关键词： Friction stir spot welding Magnesium alloys zn interlayer Hook defects

Anisotropic Electroplastic Effects on the Mechanical Properties of a Nano-Lamellar Austenitic Stainless Steel

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Acta Metallurgica Sinica(English Letters) 2021年第4期34卷 534-542页

作者： Y.R.Ma H.J.Yang D.D.Ben X.H.Shao Y.z.Tian q.wang z.F.zhang Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Sciences and Technology of ChinaHefei230026China Shenyang National Laboratory of Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang110016China

Effects of electropulsing treatment(EPT)on the microstructural evolution and mechanical properties of a cold-rolled 316 L austenitic stainless steel with nano-lamellar structure were *** EPT experiments were carried out with the electric current direction along the rolling direction(RD)and the transverse direction(TD)of the samples,*** anisotropic electroplastic effects for the RD and TD specimens,i.e.,reduced hardness/strength and enhanced ductility,were obtained owing to the different recrystallization behaviors of the RD and TD specimens during *** RD specimens after EPT with larger recrystallized grain size and higher volume fraction of recrystallization show lower strength and higher elongation than that of the TD *** main reason might be attributed to the change of the current direction in the two kinds of samples,which results in the different sensitivity of the microstructures to thermal and athermal effects during EPT.

关键词： Stainless steel Electroplastic effect Electropulsing Recrystallization Anisotropy Strength Plasticity

The Novel Mechanical Property of Tongue of a Woodpecker

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Journal of Bionic Engineering 2009年第3期6卷 214-218页

作者： P zhou X q Kong C W Wu z Chen National Key Laboratory for Structural Analysis of Industrial Equipment Dalian University of Technology Department of Civil and Environmental Engineering University of Missouri

Biomaterials such as bone,teeth,nacre and silk are known to have superior mechanical properties due to their specific nanocomposite *** we report that the woodpecker's tongue exhibits a novel strength and flexibility due to its special composite micro/*** tongue consists of a flexible cartilage-and-bone skeleton covered with a thin layer tissue of high strength and *** the interface between the cartilage-and-bone skeleton and the tissue layer,there is a hierarchical fiber-typed *** is this special design of the tongue that makes the woodpeckers efficient in catching the insects inside *** special micro/nanostructures of the woodpecker's tongue show us a potential method to enhance the interfacial connection between soft and hard material layers for bio-inspired composite system designs.

关键词： woodpeckcr hyoid cartllage multilevel structure tensile strength

Stamping Robust Design Method and Its Application

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上海交通大学学报 2004年第z2期38卷 161-165页

作者： z.q. Lin Jian Ai Weigang zhang Shuhui Li School of Mechanical Engineering Shanghai Jiaotong Univ. Shanghai200030 China Baoshan Iron&Steel Co. ltd Baoshan Shanghai China School of Mechanical Engineering Shanghai Jiaotong Univ. Shanghai200030 China School of Mechanical Engineering Shanghai Jiaotong Univ. Shanghai200030 China

The application of the robust design to stamping is discussed in the paper. The regression equation of the quality index and its influencing factors can be attained by using method of central composite design. Stamping computer simulation takes the place of real stamping experiments to fulfill the special experimental conditions. The real stamping experiments prove the correctness and the feasibility of the stamping robust design method-central composite design.

关键词： robust design central composite design computer simulation integrated quality index

Microstructure Evolution of in situ (Ti3AlC+Ti5Si3 )/Ti3Al Composite Sheet with a Novel quasi-continuous Chain Reinforcement Distribution Architecture Prepared by Using Roll Bonding and Reaction Annealing

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Journal of Materials Science & Technology 2013年第12期29卷 1191-1196页

作者： J.C.Pang G.H.Fan X.P.Cui A.B.Li L.Geng z.z.zheng q.W.wang School of Materials Science and Engineering Harbin Institute of Technology

The Ti3Al matrix composite sheet with a novel quasi-continuous chain reinforcement distribution was prepared by using roll bonding and subsequent reaction annealing with pure Ti and SiCp/Al *** (Ti3AlC t Ti5Si3) reinforcements were produced by in situ reaction of the as-rolled Tie(SiC p/Al) laminated composite sheet after a two-stage annealing treatment including first annealing at 660 C and second annealing at 1250 *** microstructure evolution during the reaction annealing was *** the first reaction annealing,TiAl3was formed,and the SiC particles were pushed together due to the Kirkendall effect,and after the second reaction annealing,Ti3Al,Ti3AlC and Ti5Si3were *** addition,the reinforcement distribution presents a quasi-continuous chain microstructure in Ti3Al matrix composite sheet.

关键词： Composite Intermetallic Fabrication Reaction synthesis

Tensile Elastic Behavior of a zr-Cu-Ag-Al Bulk Metallic Glass

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Journal of Materials Science & Technology 2014年第6期30卷 595-598页

作者： q.P.Cao J.B.Jin q.Yu X.D.wang D.X.zhang Y.Jiang J.z.Jiang International Center for New-Structured Materials (ICNSM) State Key Laboratory of Silicon MaterialsDepartment of Materials Science and Engineering Zhejiang University Department of Mechanical Engineering University of Nevada Reno NV 89557 USA State Key Laboratory of Modern Optical Instrumentation Zhejiang University

Tensile elastic behavior of bulk zr46（Cu4.5/5.5Ag1/5.5）46Al8 metallic glass was experimentally investigated. It exhibited linear and non-linear time-independent elastic deformation with a demarcative stress of approximately 500 MPa within the timescale in the present work, and repeated loading-unloading before yielding did not alter stress-strain relationship. The pure linear elastic strain limit is 0.6%, significantly lower than 2% as generally reported, but still much higher than 0.1% observed for typical crystalline alloys. Deviation from linear elastic behavior at stresses higher than 500 MPa is explained here as a macroscopic manifestation of local fluctuations in elastic strain, which becomes pronounced at stresses higher than the critical value. The occurrence of non-linear elasticity is possibly also related to the sinusoidal relationship between shear stress and atomic displacement.

关键词： Bulk metallic glass Tension test Elastic-plastic deformation

Reducing force transmissibility in multiple degrees of freedom structures through anti-symmetric nonlinear viscous damping

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Acta Mechanica Sinica 2012年第5期28卷 1436-1448页

作者： z.-K.Peng z.-q.Lang G.Meng S.A.Billings State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Department of Automatic Control and Systems Engineering University of Sheffield

In the present study, the Volterra series theory is adopted to theoretically investigate the force transmissibility of multiple degrees of freedom （MDOF） structures, in which an isolator with nonlinear anti-symmetric viscous damping is assembled. The results reveal that the anti-symmetric nonlinear viscous damping can significantly reduce the force trans- missibility over all resonance regions for MDOF structures with little effect on the transmissibility over non-resonant and isolation regions. The results indicate that the vibration isolators with an anti-symmetric damping characteristic have great potential to solve the dilemma occurring in the design of linear viscously damped vibration isolators where an increase of the damping level reduces the force transmissibility over resonant frequencies but increases the transmissibility over non-resonant frequency regions. This work is an extension of a previous study in which MDOF structures installed on the mount through an isolator with cubic nonlinear damping are considered. The theoretical analysis results are also verified by simulation studies.

关键词： Nonlinear viscous damping Force transmissibility - Vibration isolation Volterra series

Three principles for preparing Al wire with high strength and high electrical conductivity

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Journal of Materials Science & Technology 2019年第5期35卷 742-751页

作者： J.P.Hou R.Li q.wang H.Y.Yu z.J.zhang q.Y.Chen H.Ma X.M.Wu X.W.Li z.F.zhang Materials Fatigue and Fracture Division Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China National quality Supervision & Inspection Center of Electrical Equipment Safety Performance Zhejiang Huadian Equipment Testing Institute Hangzhou 310015 China Electric Power Research Institute of Liaoning Electric Power Co. Ltd. Liaoning Electric Power Co. Ltd. Shenyang 110006 China Department of Materials Physics and Chemistry School of Materials Science and Engineering Key Laboratory for Anisotropy and Texture of Materials Ministry of Education Northeastern University Shenyang 110819 China

The trade-off relation between the strength and the electrical conductivity has been a Iong-standing dilemma in metallic materials. In the study, three key principles, *** grains, sharp texture and nano-scale precipitates, were presented for preparing Al wire with high strength and high electrical conductivity based on the specially designed experiments for breaking the mutually exclusive relation between the strength and the electrical conductivity. The results show that the elongated grains could lead to a higher electrical conductivity in Al wire without sacrificing the strength;while, the sharp texture can efficiently strengthen the Al wire without influencing the electrical conductivity. Furthermore, nano-scale precipitates with proper size can simultaneously improve the strength and electrical conductivity of Al alloy wire. Under the guidance of the above three key principles, Al wires with high strength and high conductivity were prepared.

关键词： Al wire Texture Precipitates Strength Electrical conductivity