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Experimental Study and Numerical Simulation of the Casting-Forging Complex Near Net Forming of Alternator Claw-pole

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上海交通大学学报 2004年第z2期38卷 79-82页

作者： J.l.Song D.J.Hu q.C.wang H.q.Chen H.G.Guo School of Mechanical and Power Engineering Shanghai Jiaotong University Shanghai200030 China Scool of Materials Science and Engineering Taiyuan Heavy Machinery Institute Taiyuan030024 China School of Mechanical and Power Engineering Shanghai Jiaotong University Shanghai200030 China Scool of Materials Science and Engineering Taiyuan Heavy Machinery Institute Taiyuan030024 China Scool of Materials Science and Engineering Taiyuan Heavy Machinery Institute Taiyuan030024 China Scool of Materials Science and Engineering Taiyuan Heavy Machinery Institute Taiyuan030024 China

As a newly developed precision technology, casting-forging complex near net forming process is utilized to produce complex components with a short lead time, low cost and high precision, thus to accelerate the response speed of the market and enhance the competitive power of products. In this paper, the casting-forging complex near net forming process of alternator claw pole was developed and investigated with a combination of experimental and numerical simulation method. qualified near net workpiece was manufactured, mechanical parameter and relative field information during the forming process was also obtained. While the alternator claw-pole is processed with this technology, the forming force is small, the process is short and the quality of forgings is perfect. Therefore, the complex casting-forging near net forming process of claw-pole is an energy and material saving technology, which will have a vast developing and application prospect in the future.

关键词： alternator claw-pole casting-forging near net forming numerical simulation

Magnetic/Magnetostrictive Properties Together with Resistivity and Corrosion Behaviors of CoFe_2 and Its Composite with CoFe_2N

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Journal of Materials Science & Technology 2017年第7期33卷 744-750页

作者： B.q.Geng Y.q.Ma M.wang Z.l.Ding W.H.Song B.C.Zhao Key laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 China

The CoFe_2alloy（CF） was prepared by reducing CoFe_2O_4 in the H_2 ambient. Subsequently the CF sample was nitrided in the NH_3 atmosphere to produce the composite of CoFe_2N and CoFe_2. The magnetostriction, thermal expansion, resistivity and corrosion resistance of CF sample and the nitrided sample（CFN）at 1000？C were investigated. The saturation magnetostriction coefficiency λ_s and thermal expansion coefficient ？ at 300 K for the nitrided CFN were 50 ppm and 10 ppm/K, respectively, approximately equal to those for the CF sample. However, compared with CF, CFN presents a decrease in temperature coefficient R_λ（300 K） of magnetostriction by 11%. The smaller resistivity and improved corrosion resistance in the H_2SO_4 solution may expand the applications of the CoFe_2 in the fields needing lower resistivity or in the acidic environment.

关键词： CoFe alloy CoFe_2N alloy Magnetostriction Resistivity Corrosion resistance

IN　SITUlASER　RAMAN　SPECTROSCOPY　OF　THERMAl　DECOMPOSITION　OF　AMMONIUM　TUNGSTATE

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Chinese Chemical letters 1995年第12期6卷 1085-1086页

作者： li, XS Zhu, BZ wang, l Miao, YF Xin, q Chinese Acad Sci Dalian Inst Chem Phys State Key Lab Catalysis Dalian 116023 Peoples R China Henan Coll Educ Dept Chem Zhengzhou 450003 Peoples R China

The mechanism of thermal decomposition of ammonium tungstate has been studied by to situ laser Raman spectroscopy (lRS) combined with thermal gravimetric analysis (TG), differental thermal analysis (DTA) and X-ray dif...

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Timoshenko beam model for chiral materials

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Acta Mechanica Sinica 2018年第3期34卷 549-560页

作者： T.Y.Ma Y.N.wang l.Yuan J.S.wang q.H.qin Department of Mechanics Tianjin University School of Engineering Deakin University Research School of Engineering Australian National University

Natural and artificial chiral materials such as deoxyribonucleic acid （DNA）, chromatin fibers, flagellar filaments, chiral nanotubes, and chiral lattice materials widely exist. Due to the chirality of intricately helical or twisted microstructures, such materials hold great promise for use in diverse applications in smart sensors and actuators, force probes in biomedical engineering, structural elements for absorption of microwaves and elastic waves, etc. In this paper, a Timoshenko beam model for chiral materials is developed based on noncentrosymmetric micropolar elasticity theory. The governing equations and boundary conditions for a chiral beam problem are derived using the variational method and Hamilton＇s principle. The static bending and free vibration problem of a chiral beam are investigated using the proposed model. It is found that chirality can significantly affect the mechanical behavior of beams, making materials more flexible compared with nonchiral counterparts, inducing coupled twisting deformation, relatively larger deflection, and lower natural frequency. This study is helpful not only for understanding the mechanical behavior of chiral materials such as DNA and chromatin fibers and characterizing their mechanical properties, but also for the design of hierarchically structured chiral materials.

关键词： Timoshenko beam model Chiral material Chirality Deflection Microrotation

THERMAl STRUCTURAl DISORDER AND MElTING TRANSITION IN HIGH-ANGlE GRAIN-BOUNDARY: A MOlECUlAR-DYNAMICS STUDY

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Acta Metallurgica Sinica(English letters) 1998年第5期11卷 365-375页

作者： S.J.Zhao Y.C.wang J.q.You q.B.Yang l.G.Zhou H.q.Ye Xiangtan Univ Xiangtan China

A structural transition in the fcc ∑=5 (120)/[001] high-angle tilt grain-boundary(GB)is investigated by molecular-dynamics simulation. The calculations have been performed at various temperutures and the thermodynamic melting point Tm of the model system is determined by using a many-body potential fitted to copper. A thermal disorder transition in the GB region occurs well below the melting point. Our results indicate that such a transition is a continuous process and there is no evidence of premelting, which is entirely in accord with experiment results and theoretical *** we also observed that melting initiated at the interface and then propagated into the bulk quickly at or above Tm.

关键词： moleculandynamics grainboundary structural transition

Coarsening Kinetics of a Two Phase Mixture with Highly Disparate Diffusion Mobility

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Communications in Computational Physics 2010年第7期8卷 249-264页

作者： G.Sheng T.wang q.Du K.G.wang Z.K.liu l.q.Chen Department of Materials Science and Engineering Pennsylvania State UniversityUniversity ParkPA 16802USA Department of Materials Science and Engineering Iowa State UniversityAmesIA 50011USA Department of Mathematics Pennsylvania State UniversityUniversity ParkPA 16802USA Physics and Space Science Department Materials Science&Nanotechnology InstituteFlorida Institute of TechnologyMelbourneFL 32901USA

The coarsening kinetics of a two-phase mixture with a large diffusional mobility disparity between the two phases is studied using a variable-mobility Cahn Hilliard *** semi-implicit spectral numerical technique was employed,and a number of interpolation functions are considered for describing the change in diffusion mobility across the interface boundary from one phase to *** coarsening rate of domain size was measured using both structure and pair correlation functions as well as the direct computation of particle sizes in real space for the case that the coarsening phase consists of dispersed *** discovered that the average size(R)versus time(t)follows the R^(10/3)∝t law,in contrast to the conventional lSW theory,R^(3)∝t,and the interface-diffusion dominated two-phase coarsening,R^(4)∝t.

关键词： Coarsening kinetics Cahn-Hilliard equation phase-field method computer simulation

Irradiation-induced homogeneous plasticity in amorphous/amorphous nanolaminates

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Journal of Materials Science & Technology 2020年第22期54卷 70-77页

作者： l.Huang Z.q.Chen P.Huang X.K.Meng F.wang State Key laboratory for Mechanical Behavior of Material School of Materials Science and EngineeringXi'an Jiaotong UniversityXi'an710049China Institute of Materials Engineering National Laboratory of Solid State MicrostructuresCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210023China State Key laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi'an Jiaotong UniversityXi'an710049China

Achieving homogeneous plastic deformation in metallic glasses is a long-standing goal yet to be solved in materials science. Here we investigate the effect of ion irradiation on the plastic deformation behavior of ZrCu/ZrCuNiAlSi amorphous/amorphous nanolaminates(A/ANls) via nanoindentation testing. The experimental results indicate a dramatic change in deformation mode from multiple shear banding events to homogeneous compressive deformation before and after ion irradiation on the A/ANls in the areas underneath the indenter. Ion irradiation-induced changes of both fraction and distribution of free volume inside each constituent layer and interfacial state in the A/ANls may be responsible for the unusual homogeneous deformation behavior. Our results suggest that the mechanical property of A/ANls could be modified by tuning both the inner and interfacial structure via ion irradiation.

关键词： Metallic glasses Ion irradiation Plastic deformation Nanolaminates Interface

Inhibiting effect of I-phase formation on the plastic instability of the duplex structured Mg-8li-6Zn-1.2Y(in wt.%)alloy

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Journal of Magnesium and Alloys 2023年第6期11卷 2196-2204页

作者： B.J.wang D.K.Xu X.q.Zhuang l.Y.Sheng School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang110159China Key laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Peking University Shenzhen InstituteShenzhen Key Lab Human Tissue Regenerate&RepairShenzhen 518057China

In this work,the tensile behaviors of Mg-8%li and Mg-8%li-6%Zn-1.2%Y alloys at ambient temperature were investigated and *** revealed that the plastic instability of Mg-8%li alloy was quite remarkable and the variation range of serrated flowing stress can reach5 *** the Mg-8%li-6%Zn-1.2%Y alloy,the formation of I-phase(Mg_(3)Zn_(6)Y)can simultaneously enhance the tensile strength and eliminate the plastic instability phenomenon,whilst its ductility was *** in-situ tensile tests revealed that for the Mg-8%li alloy,the severity and number of slip traces present in bothα-Mg andβ-li matrix phases increased remarkably with the applied tensile ***,slip traces were quite fine inβ-li matrix phase and could be clearly observed when the applied tensile strain exceeded 18%.Due to the incompatibility of plastic deformation occurred in two matrix phases,the induced strain concentration atα-Mg/β-li interfaces caused their subsequent *** the Mg-8%-6%Zn-1.2%Y alloy,the I-phase distributed atα-Mg/β-li interfaces suppressed the plastic deformation ofα-Mg matrix phase and the tensile strain was dominated by theβ-li matrix phase,resulting in the disappearance of plastic ***,the plastic strain would preferentially concentrate at I-phase/β-li interfaces and subsequently induced the cracking of I-phase.

关键词： Mg-li alloys Microstructure Plastic deformation Basal slip Cracking

Microstructure evolution and mechanical properties at high temperature of selective laser melted AlSi10Mg

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Journal of Materials Science & Technology 2021年第3期62卷 162-172页

作者： Y.Cao X.lin q.Z.wang S.q.Shi l.Ma N.Kang W.D.Huang State Key laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Key laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China

In this study,the microstructure and tensile properties of selective laser melted AlSilOMg at elevated temperature were investigated with focus on the interfacial ***-situ SEM and in-situ EBSD analysis were proposed to characterize the microstructural evolution with *** as-fabricated AlSilOMg sample presents high tensile strength with the ultimate tensile strength(UTS)of~450 MPa and yield strength(YS)of~300 MPa,which results from the mixed strengthening mechanism among grain boundary,solid solution,dislocation and Orowan looping *** holding at the temperature below 200℃for 30 min,the micro structure presents little change,and only a slight decrement of yield strength appears due to the relief of the residual ***,when the holding temperature further increases to 300℃and 400℃,the coarsening and precipitation of Si particles inα-Al matrix occur obviously,which leads to an obvious decrease of solid solution *** the same time,matrix softening and the weakness of dislocation strengthening also play important *** the holding temperature reaches to 400℃,the yield strength decreases significantly to about 25 MPa which is very similar to the as-cast Al *** might be concluded that the YS is dominated by the matrix *** the softening mechanism counteracts work hardening,the extremely high elongation occurs.

关键词： Selective laser melting AlSi10Mg Microstructure In-situ EBSD High temperature tensile property