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INFLUENCE OF SURFACE-ACTIVE ELEMENTS ON FLUID FLOW OF MIG WELDPOOL

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Acta Metallurgica Sinica(English Letters) 2004年第2期17卷 189-193页

作者： J.S.sun J.q.Gao Y.Feng Y.W.Luan MOEKeyLab.ofLiquidStructureandHeredityofMaterials ShandongUniversityJi＇nan250061China TechnologyCenter Ji＇nanIronandSteelGroupJi＇nan250101China

A mathematical model describing the behavior of metal inert gas (MIG) welding isformulated in the paper. By means of numerical simulation, the influence of surface-active elements on fluid flow of MIG weldpool is studied. The calculation resultsshow that by adding surface-active elements, the fluid flow behavior is drasticallychanged and the flow fluid flows from lower to upper in vertical direction at the rearof weldpool (w>0). The physical phenomenon is explained from the viewpoint of fluidflow behavior of weldpool that the properties of weld metal is greatly improved andthe content of diffused hydrogen is reduced, thus providing a basis for developing newwelding materials.

关键词： surface-active elements fluid flow numerical analysis

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

EXTRUSION DIE CAE OF THE STEEL REINFORCED PLASTIC PIPE

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Acta Metallurgica Sinica(English Letters) 2004年第3期17卷 303-306页

作者： W.q.Ma H.Y.sun D.C.Kang K.D.Zhao Harbin Institute of Technology Harbin 150001 China Daqing Oilfield Postdoctoral Workstation Daqing 163453 ChinaHarbin University of Science and Technology Harbin 150080 China Daqing Oilfield Postdoctoral Workstation Daqing 163453 ChinaHarbin Institute of Technology Harbin 150001 ChinaHarbin Institute of Technology Harbin 150001 China

The steel reinforced plastic pipe is a new kind of pressure pipe. It is made up with steelwires and plastic. Because reinforced skeleton of the steel wire increase the complexityof plastic flow during the extrusion phase, the traditional design criteria of extrusiondie is not suitable. The study on extrusion die of the kind of pipe is very importantstep in produce development. Using finite element (FE) method in this paper, theflow rule of molten plastic inside the die has been predicted and a groap of optimalstructural parameters was obtained. These results are helpful for reducing the designcycle and improve the quality of the final product.

关键词： steel reinforced plastic pipe extrusion die computer aid engineering(CAE)

Enhancing strength and ductility of AlSi10Mg fabricated by selective laser melting by TiB_(2)nanoparticles

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Journal of Materials Science & Technology 2022年第14期109卷 254-266页

作者： Y.K.Xiao H.Chen Z.Y.Bian T.T.sun H.Ding q.Yang Y.Wu q.Lian Z.Chen H.W.Wang State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China School of Materials Science&Engineering Shanghai Jiao Tong UniversityShanghai 200240China

In the metallic components fabricated by the emerging selective laser melting(SLM)technology,most strategies used for strengthening the materials sacrifice the ductility,leading to the so-called strengthductility *** the present study,we report that the strength and ductility of materials can be enhanced simultaneously by introducing nanoparticles,which can break the trade-off of the metallic *** the case of in-situ nano-TiB_(2)decorated AlSi10Mg composites,the introduced nanoparticles lead to columnar-to-equiaxed transition,grain refinement and texture *** increasing content of nanoparticles,the strength increases ***,the ductility first increases and then *** results show that the ductility is controlled by the competition between the crack-induced catastrophic fracture and ductile fracture associated with dislocation *** first increase of ductility is mainly attributed to the suppression of crack-induced catastrophic fracture when TiB_(2)nanoparticles *** the further increase of TiB_(2)nanoparticles,the subsequent decrease of ductility is mainly controlled by dislocation ***,the materials will exhibit the optimum strength and ductility combination in a certain range of TiB_(2)*** study clarifies the physical mechanism controlling ductility for nano-TiB_(2)decorated Al Si10Mg composites,which provides the insights for the design of structural materials.

关键词： Selective laser melting Aluminium matrix composites Ductility Mechanical behavior Dislocations Cracks

Embedding laser-generated CdTe nanocrystals into ultrathin ZnIn_(2)S_(4) nanosheets with sulfur vacancies for boosted photocatalytic H_(2) evolution

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Journal of Materials Science & Technology 2023年第35期166卷 113-122页

作者： Z.G.Tai G.T.sun X.H.Zhang X.B.Yang T.Wang Z.Y.Fang q.Ye L.C.Jia H.q.Wang State Key Laboratory of Solidification Processing Center for Nano Energy MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China School of Materials Science and Engineering Shaanxi Normal UniversityXi’an 710119China

To suppress the inner charge recombination and inject vast electrons,CdTe nanocrystals are embedded into ultrathin ZnIn_(2)S_(4) nanosheets to construct ZnIn_(2)S_(4)/CdTe heterostructures,where the nanocrystals are generated by a laser irradiation *** optimal ZnIn_(2)S_(4)/CdTe heterojunction exhibits an excellent catalytic activity of 24.3 mmol/h/g,which is relatively high among the ZnIn_(2)S_(4)-based photocatalysts with-out noble *** enhancement is ascribed to a win-win mechanism of nanoscale heterojunctions and sulfur *** strong electron coupling effect,which is verified by density functional the-ory(DFT)calculations,impels the photo-generated electrons transfer from CdTe to ZnIn_(2)S_(4),boosting the charge ***,the sulfur vacancies existing in ZnIn_(2)S_(4) can capture photoelectrons and act as active sites,facilitating the H_(2) generation *** addition,the ZnIn_(2)S_(4) base and the ZnIn_(2)S_(4)/CdTe heterojunction also possess an evident photothermal effect and renewable cycle phenomena,enhancing the photocatalytic *** research provides new insights into the regulation of charge transfer through embedding nanocrystals.

关键词： Photocatalysis Hydrogen evolution Laser irradiation Heterostructure Sulfur vacancies

EFFECTS OF COMBINED ADDITIONS OF TUNGSTEN AND MOLYBDENUM ON THE CREEP PROPERLIES OFFe_3Al-BASED ALLOYS

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Acta Metallurgica Sinica(English Letters) 2000年第6期13卷 1136-1140页

作者： X.q. Yu and Y.S. sun (Department of Materials Science and Engineering, Southeast University, Nanjing 210096, China) Dep. of Materials and Eng. Southeast Univ. Nanjing 210096 China

Effects of combined additions of tungsten and molybdenum on the creep properties of Fe3AI-based alloys have been investigated. Results show that combined additions of tungsten and molybdenum increase significantly the creep rupture life of the Fe3Al base alloys at high temperature. TEM analysis of the alloys containing tungsten plus molybdenum indicates that both solid-solution strengthening and precipitation harden- ing make the significant increase of creep rupture life.

关键词： Fe3Al creep property tungsten molybde8

EFFECT OF ELONGATED GRAIN STRUCTURE ON THEMECHANICAL PROPERTIES OF AN Fe_3Al-BASEDALLOY

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Acta Metallurgica Sinica(English Letters) 1997年第4期10卷 358-362页

作者： X.q. Yu and Y.S. sun (Department of Materials Science and Engineering, Southeast University, Nanjing 210096, China) Southeast Univ Nanjing China

The effect of hot-rolling processing on microstructure as well as the relationship between the elongated grain structure and tensile properties are investigated. The results indicate that the elongated grain structure influences the tensile properties and creep rupture life of Fe3Al alloy significantly. For the better strength and ductility at RT,a thinner elongated grain structure is desirable. When the elongated grain size is increased, the tensile properties will be decreased. On the other hand, the creeP rupture life at 600℃ is increased with the increase of elongated grain size.

关键词： Fe_3Al-based alloy microstructure tensile property

Effect of icosahedral clusters on β-relaxations in metallic glasses

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Chinese Physics B 2017年第1期26卷 86-90页

作者： X q Gao Y T sun Z Wang M Z Li H Y Bai Institute of Physics Chinese Academy of Sciences Beijing 100190 China Department of Physics Renmin University of China Beijing 100872 China

The most pronounced β-relaxation was found in the Y-based binary metallic glasses（MGs）. The correlation betweenβ-relaxation and local atomic structure was studied. The dynamic mechanical measurements were performed for three chosen binary systems： Zr-, Ti-, and Y-based MGs. The experimental results show that, in each system,the larger negative enthalpy of mixing（？Hm） between the component elements makes β-relaxation become more pronounced. The less negative value of ？Hm facilitates the formation of icosahedral clusters, which have a pinning effect on the excitation of β-relaxations and correspondingly make the β-relaxation become less pronounced. These chemical effects on β-relaxations can only be compared in the same MG system, and it is not suitable for the comparison between different systems due to the different features of the major metallic elements.

关键词： metallic glass β-relaxation enthalpy of mixing icosahedral clusters

MICROSTRUCTURES AND OXIDATION RESISTANCE OF Fe_3Al WELD OVERLAY

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Acta Metallurgica Sinica(English Letters) 2001年第4期14卷 253-256页

作者： X.G. Mi X.q. Yu, Y.S. sun and J.R. sun Department of Materials Science and Engineering, Southeast University, Nanjing 210096, China Dept. of Mat. Sci. Southeast Univ. Nanjing 210096 China

Using the Fe3Al electrode through manual arc surfacing (MAS), Fe3Al coatings were deposited on the stainless steel substrate. The microstructures, hardness and oxidation resistance of the weld overlay were investigated. The results show that crack-free overlays can be obtained when pre-heating the substrate at 500°C and postweld heat treatment at 700°C are used. Elements of Al, Cr and Ni, etc. transfer between the substrate and the overlay, but this does not influence the microhardness of the substrate and the Fe3Al overlay. Oxidation tests show that the Fe3Al overlay has excellent oxidation resistance in comparison with the stainless steel substrate at 800°C and 900°C.

关键词： Aluminum Intermetallics Iron Microstructure Oxidation resistance