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Annealing-induced Hardening in a Nanostructured Low-carbon Steel Prepared by Using Dynamic Plastic Deformation

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Journal of Materials Science & Technology 2014年第8期30卷 731-735页

作者： L.X.Sun N.R.tao M.Kuntz J.q.Yu K.Lu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences Corporate Sector Research and Advance Engineering Production Technology 1 Materials and Process Engineering MetalsRobert Bosch GmbHP. O. Box 30 02 4070442 StuttgartGermany Research and Technology Center Asia Pacific Bosch(China) Investment Ltd.

Lamellar nanostructures were induced in a plain martensitic low-carbon steel by using dynamic plastic deformation at room *** nanostructured steel was hardened after annealing at 673 K for20 min,with a tensile strength increased from 1.2 GPa to 1.6 *** the remained nanostructures and annealing-induced precipitates in nano-scale play key roles in the hardening.

关键词： Nanostructure Annealing Precipitation hardening Low-carbon steel Dynamic plastic deformation

T-q diagram analyses and entransy optimization of the organic flash cycle(OFC)

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Science China(Technological Sciences) 2015年第4期58卷 630-637页

作者： wANG wen Hua CHENG Xue tao LIANG Xin Gang Key Laboratory for Thermal Science and Power Engineering of Ministry of Education School of AerospaceTsinghua University

The electrical power generation from low temperature heat source attracts more and more attentions but the temperature mismatching between the heat sources and working medium in the organic Rankine cycle(ORC)becomes an *** organic flash cycle(OFC)is an effective solution to this *** this paper,the OFC is analyzed by the concept of entransy loss and the T-q(temperature-heat flow rate)diagram for the heat-work *** equations for cycles of the basic OFC and the OFC whose heat source is the exhaust gas of the turbine in a Brayton cycle(the combined cycle)are derived theoretically and the results indicate that larger entransy loss rate leads to larger output power with prescribed inlet parameters of the hot stream in the discussed cases,which is displayed by the T-qdiagram *** numerical examples demonstrate that the optimal mass flow rate of the working medium for the maximum entransy loss rate is the same as that for the maximum output *** T-qdiagram analyses is in accordance with the numerical *** concept of entransy loss can be used as the criteria for the OFC optimization.

关键词： OFC T. q diagram entransy loss combined cycle optimization

EFFECT OF Mo AND Mo_2C ON THE MICROSTRUCTURE AND PROPERTIES OF THE CERMETS BASED ON Ti(C,N)

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Acta Metallurgica Sinica(English Letters) 2008年第3期21卷 211-219页

作者： S.q. Zhou w. Zhao w.H. Xiong Y.N. Zhou School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China The University of waterloo Waterloo ON N2L3G1 Canada

Effect of Mo and Mo2 C on the microstructure and properties of Ti（C,N）-based cermets was investigated in this article. The results have indicated that the weight percentage of Mo from 5 to 10 can reduce Ti（C,N） grain diameter and thickness of the rim, and Ti（C,N） grain can be wetted by Ni-Cu-Mo liquid so as to get small contiguity of Ti（C,N） grain. In that way, the transverse rupture strength of Ti（C,N）-based cermets has reached 1800-1900 MPa; the fracture toughness has been due to 16-18 MPa.m1/2. But 15 wt pct Mo was not more effective on Ti（C,N）-based cermets, because the thickness of the rim becomes larger. In the circumstance of Mo2 C, 5 wt pct Mo2 C was good for microstructure and properties of Ti（C,N）-based cermets, but 11 wt pct Mo2C has resulted in larger contiguity of Ti（C,N） grain and big Ti（C,N） grain diameter so as to reduce transverse rupture strength and fracture toughness. So that, the effect of Mo on Ti（C,N）-based cermets is better than Mo2C.

关键词： Cermet Transverse rupture strength (TRS) Contiguity Fracture toughness

Localized space-tim e method of fundamental solutions for three-dimensional transient diffusion problem

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Acta Mechanica Sinica 2020年第5期36卷 1051-1057,I0002页

作者： L.qiu J.Lin q.-H.qin w.Chen International Center for Simulation Software in Engineering and Sciences College of Mechanics and MaterialsHohai UniversityNanjing 210098China College of Engineering and Computer Science Australian National UniversityCanberraACT 2601Australia State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Acoustic Institute of AcousticsChinese Academy of SciencesBeijing 100190China

A localized space-time method of fundamental solutions(LSTMFS)is extended for solving three-dimensional transient diffusion problems in this *** interval segmentation in temporal direction is developed for the accurate simulation of long-time-dependent diffusion *** the LSTMFS,the whole space-time domain with nodes arranged i divided into a series of overlapping subdomains with a simple *** each subdomain,the conventional method of fundamental solutions is utilized and the coefficients associated with the considered domain can be explicitly *** calculating a combined sparse matrix system,the value at any node inside the space-time domain can be *** experi-ments demonstrate that high accuracy and efficiency can be simultaneously achieved via the LSTMFS,even for the problems defined on a long-time and quite complex computational domain.

关键词： Localized spacetime method of fundamental solutions Meshless method Long-time evolution Transient diffusion

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

PARAMETRIC STUDY FOR THE PREPARATION OF ALIGNED SINGLE-wALLED CARBON NANOTUBES BY ANODE-ARC DISCHARGE METHOD

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 261-268页

作者： J.F.Dai q.wang w.X.Li Z.q.wei G.J.Xu StateKeyLaboratoryofNewNonferrousMetalMaterials DepartmentofPhysicsLanzhouUniversityofTechnologyLanzhou730050China StateKeyLaboratoryofNewNonferrousMetalMaterials InstituteofMaterialsLanzhouUniversityofTechnologyLanzhou730050China

well aligned quasi-straight single-walled carbon nanotubes (SwCNTs) and straight SwCNTs bundle have been prepared in large scale by anode-arc vaporization of gr aphite with metallic catalysts. Various parameters such as the catalyst preparat ion, the kinds and pressure of the buffer gases, the quantity of anode-arc curre nt intensity, and the method of purification have been examined. The influence o f these parameters on the deposited carbon yield is reported, together with obse rvations of the produced material. Improvement in synthetic techniques has resul ted in the optimal conditions for the production of large quantities of high qua lity SwCNTs in our semi-continuous synthesis method. The formation of carbon nan otubes (CNTs) was studied briefly in this paper. Owing to the magnetic pinching effect of arc current, the CNTs arrange in parallel lines along the arc current direction.

关键词： carbon nanotubes anode-arc preparation catalyst

Screening and Identifying Two Specifi c Molecular Markers in Maintainer Line of Cytoplasmic Male Sterility Cauliflower (Brassica oleracea var. botrytis)

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分子植物育种 2007年第2期5卷 269-270页

作者： C.G. wang 　J.M. Gao　 H. Li　 Y. Gu　 X.q. Chen　 w.q. Song College of Life Sciences Nankai University Tianjin 300071 China Department of agronomy Tianjin agricultural University Tianjin 300384 China Department of Horticulture Tianjin Agricultural University Tianjin 300384 China

Cytoplasmic male sterility (CMS) is a maternally inherited trait that prevents the production of function pollen, but maintains female fertility. It has been widely used in breeding programs to product F_1 hybrid seed

关键词：分子标记花椰菜细胞质种植技术

NUMERICAL SIMULATION OF EXTRUSION OF COMPOSITE POwDERS PREPARED BY HIGH ENERGY MILLING

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Acta Metallurgica Sinica(English Letters) 2004年第1期17卷 51-54页

作者： X.q.Li w.P.Chen w.Xia q.L.Zhu Y.Y.Li E.D.wang College of Mechanical Engineering South China University of Technology.Guangzhou 510640 China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

Based on the characteristic of high energy milling and the micromechanics of composite material, a plastic constitutive equation is implemented for milled composite powders. To check the equation, the extrusion of Ti/Al composite powders prepared by high energy milling was simulated. It was from the numerical analysis that the predicted extrusion pressure mounted up with milling time and extrusion ratio increasing, which was perfect agreement with experimental results.

关键词： high energy milling composite powder plastic constitutive equation extrusion numerical simulation

STUDY ON THE MECHANISM OF GRAPHITIZATION IN MOLTEN CAST IRON PROMOTED BY ELECTROPULSE DISCHARGE

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Acta Metallurgica Sinica(English Letters) 2004年第6期17卷 790-794页

作者： G.w.Chang J.S.wang J.Z.wang q.G.Xue O.q.Zhou D.q.Cang Dept.Materials＆ChemicalEng. LiaoningInstituteofTechnologyJinzhou121001China SchoolofMetallurgy BeijingUniversityofScience＆Technology.Beijing100083China

From the points of both molten cast iron structure and the appearing ratio of electrons in outer-layer of different atoms, analysis on enhancement mechanism of graphitization ability after processing of the iron by pulse electric discharge has been made, and the theory has been proofed by corresponding experiments. The results show that when the molten cast iron is being processed by pulse electric discharge, both the size of crystal embryos that composed by Fe and C atoms as well as the number of clusters can be reduced, even be separated by such discharging; consequently results in the segre- gation of C atoms in the molten cast iron near the cathode of discharging. The nucleation of graphite in these areas of the iron has been promoted at the discharging temperature; even though such degree has not been reached, the most favorable nucleation conditions of graphite can be at least created. Under the preconditions of not breaking up the graphite crystal embryos, with proper adjustment of discharging frequency, the stronger of the electric field and the longer of the pulsation treatment time are, the more graphitization ability of the molten cast iron is. The theoretical analysis on the above rules consists well with experimental results.

关键词： pulsed electric field molten iron-solution graphitization