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RESEARCH ON AS-CAST gRAIN REFININg TECHNOLOgy By INOCULATINg CLEAN STEEL WITH TITANIUM OXIDE

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Acta Metallurgica Sinica(English Letters) 2003年第5期16卷 379-384页

作者： g.g.Cheng M.L.wang X.E.yang y.L.Li y.g.wang L.y.wa.g P.Zhao UniversityofScienceandTechnologyBeijing Beijing100083China CentralIronandSteelResearchInstitute Beiiing100081China

Precipitation condition and nucleation of Ti2O3 during solidification of clean steel have been studied. The behavior of Ti2O3 during solidification as well as possibility of using Ti2O3 to refine as-cast grains as heterogeneous nucleation sites is discussed. It is shown that Ti2O3 can be formed provided that the steelmaking and solidification process is controlled strictly. And inoculating clean steel with Ti2O3 is an effective way to refine as-cast grains.

关键词： clean steel solidification Ti2O3 precipitation

Effect of forced-air cooling on the microstructure and age-hardening response of extruded Mg-gd-y-Zn-Zr alloy full with LPSO lamella

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Journal of Materials Science & Technology 2021年第14期73卷 66-75页

作者： S.Z.Wu T.Nakata g.Z.Tang C.Xu X.J.wang X.W.Li X.g.Qiao M.y.Zheng L.geng S.Kamado g.H.Fan School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Research Center for Advanced Magnesium Technology Nagaoka University of TechnologyNagaoka 940-2188Japan School of Material Science and Engineering Harbin University of Science and TechnologyHarbin 150040China Key Laboratory for Light-weight Materials Nanjing Tech UniversityNanjing 211816China

The homogenized Mg-8.2 gd-3.8 y-1.0 Zn-0.4 Zr(wt.%)alloy full of plate-shaped long period stacking ordered(LPSO)phases was hot extruded in the atmosphere and cooled by the forced-air,then the effect of forced-air cooling on the microstructure and age-hardening response of the alloy was investigated in this *** results show that in comparison with the extruded sample cooling in the atmosphere,the forced-air cooling restricts dynamic recrystallization(DRX)and brings about finer dynamic recrystallized(DRXed)grain size,stronger basal texture and higher dislocation ***,the forced-air cooling promotes the dynamic precipitation in the DRXed regions and facilitates formation of plate-shaped LPSO phases andγ’phases with smaller interspacing in the unrecrystallized(un DRXed)regions,then slightly restricts the precipitation ofβphases during *** peak-ageing treatment,the extruded sample with forced-air cooling shows superior tensile properties with a tensile yield strength of 439 MPa,an ultimate tensile strength of 493 MPa,and elongation to failure of 18.6%.

关键词： Mg-RE alloy LPSO phase Dynamic recrystallization Precipitation Mechanical properties

IMPROVEMENT OF DISPERSION ABILITy OF NANOMETER PARTICLES By MEANS OF PLASMA POLyMERIZATION

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Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 73-76页

作者： g.Q. Zhang X.g. guo y.M. Liu y.J. ge Beijing Institute of Printing Beijing 102600 China

In order to find a new way to improve the dispersion ability of nanometer material, an investigation on preparation of thin film with low surface energy on the surface of nanometer material by means of plasma polymerization has been done. Some physical behaviors and chemical constitution of prepared film as well as the influence of polymerized film on nanometer material were tested. All the experimental results showed that this is a possible way to improve the dispersion ability of nanometer materials.

关键词： plasma polymerization nanometer material

grain refinement mechanism of Mg-3Sn-1Mn-1La alloy during accumulative hot rolling

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Journal of Materials Science & Technology 2021年第32期91卷 251-261页

作者： Z.y.Zhao R.g.guan y.F.Shen P.K.Bai School of Materials Science and Engineering North University of ChinaTaiyuan 030051China bEngineering Research Center of Continuous Extrusion Ministry of EducationDalian Jiaotong UniversityDalian 116028China Key Laboratory for Anisotropy and Texture of Materials Northeastern UniversityShenyang 110004China

We elucidate the effect of lanthanum(La) on the grain refinement of Mg-3 Sn-1 Mn alloy during accumulative hot rolling. The lath-shaped Mg_(2) Sn phase in the Mg-3 Sn-1 Mn alloy is firstly broken and spheroidized,and then the size increases and coarsens with the increase of rolling reduction, most of Mg_(2) Sn move from grain boundary to grain and are homogeneously distributed within the matrix. However, the plate-shaped Mg Sn La compound in Mg-3 Sn-1 Mn-1 La gradually becomes fine, spheroidized, and homogeneously distributed. The grain sizes of Mg-3 Sn-1 Mn and Mg-3 Sn-1 Mn-1 La alloys become fine through dynamic recrystallization(DRX), though the grain refinement of Mg-3 Sn-1 Mn-1 La alloy is better compared to the Mg-3 Sn-1 Mn alloy. A large number of uniformly distributed spherical Mg Sn La compounds pin the dislocations, thus increasing the dislocation density. Hence, the driving force for DRX increases and promotes the formation of deformation bands and more twins, providing the sites for DRX nucleation and growth.

关键词： Mg alloy grain refinement Dynamic recrystallization Accumulative hot rolling

SyNTHESIS AND MICROSTRUCTURE OF SUPERHARD TiN/SiN_x MULTILAyER THIN FILMS

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 242-248页

作者： Z.F.Zhou y.g.Shen y.W.Mai K.y.Li AdvancedCoatingsAppliedResearchLaboratory（ACARL） DepartmentofManufacturingEngineeringandEngineeringManagementCityUniversityofHongKongKowloonHongKongChina CentreforAdvancedMaterialsTechnology（CAMT） SchoolofAerospaceMechanicalandElectronicEngineeringUniversityofSydneySydneyNSW2006Australia

Multilayer thin films of TiN/SiNx have been deposited onto heated Si 100 substra tes (200℃) by reactive dc-magnetron sputtering from Ti and Si targets in an Ar- N2 gas mixture. The rotation speed of the substrate holder was varied from 1 to 20rpm, while target currents were held constant, to produce bilayer periods vary ing from approximately 22 to 0.6nm. These multilayer films were characterized by atomic force microscopy (AFM), cross-sectional transmission electron microscopy (TEM), scanning electron microscopy (SEM), and microhardness measurements. TEM and SEM studies showed elimination of columnar structure in TiN, owing to the in corporation of amorphous SiNx layers. The crystallinity of TiN and amorphous nat ure of SiNx were confirmed by high resolution TEM. An optimum rotation speed was observed, at which hardness was a maximum. The resulting bilayer period was fou nd to be approximately 1.6nm, which resulted in a significant improvement in mic rohardness (~57gPa). The rms surface roughness for this film was less than 1.5nm .

关键词： multilayers hardness supermodulu s stress TiN/SiNx

Correlation between depassivation and repassivation processes determined by single particle impingement:Its crucial role in the phenomenon of critical flow velocity for erosion-corrosion

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Journal of Materials Science & Technology 2021年第30期89卷 158-166页

作者： L.L.Li Z.B.wang S.y.He y.g.Zheng CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Department of Physics Southern University of Science and TechnologyGuangdong 518055China

The correlation between depassivation and repassivation processes,which is significant in erosioncorrosion,was quantitatively investigated by single particle impingement tests at various flow velocities and impact *** results show that both repassivation and depassivation processes are associated with the kinetic energy of solid particle,and demonstrate that the repassivation is retarded by *** phenomenon probably results from the depassivation-induced microstructure *** this basis,the dependence of critical flow velocity(CFV)for erosion-corrosion on the solid particle concentration and diameter is further theoretically predicted and experimentally ***,the crucial role of depassivation-repassivation in CFV phenomenon is further highlighted.

关键词： Erosion-corrosion Stainless steel Depassivation-repassivation Single particle impact Passive film

Alkali control of high-grade metamorphism and granitization

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geoscience Frontiers 2014年第5期5卷 711-727页

作者： Oleg g.Safonov Leonid y.Aranovich Institute of Experimental Mineralogy RAS ChernogolovkaMoscow RegionRussia Department of Petrology Moscow State UniversityMoscowRussia Department of geology.University of Johannesburg Johannesburg.South Africa Institute of geology of Ore Deposits PetrographyMineralogy and Geochemistry

We review petrologic observations of reaction textures from high-grade rocks that suggest the passage of fluids with variable alkali activities. Development of these reaction textures is accompanied by regular compositional variations in plagioclase, pyroxenes, biotite, amphibole and garnet. The textures are interpreted in terms of exchange and net-transfer reactions controlled by the K and Na activities in the fluids. On the regional scale, these reactions operate in granitized, charnockitized, syenitized etc. shear zones within high-grade complexes. Thermodynamic calculations in simple chemical systems show that changes in mineral assemblages, including the transition from the hydrous to the anhydrous ones, may occur at constant pressure and temperature due only to variations in the H2O and the alkali activities. A simple procedure for estimating the activity of the two major alkali oxides, K2O and Na2O, is imple- mented in the TWQ software. Examples of calculations are presented for well-documented dehydration zones from South Africa, southern India, and Sri Lanka. The calculations have revealed two end-member regimes of alkalis during specific metamorphic processes： rock buffered, which is characteristic for the precursor rocks containing two feldspars, and fluid-buffered for the precursor rocks without K-feldspar. The observed reaction textures and the results of thermodynamic modeling are compared with the results of available experimental studies on the interaction of the alkali chloride and carbonate-bearing fluids with metamorphic rocks at mid-crustal conditions. The experiments show the complex effect of alkali activities in the fluid phase on the mineral assemblages. Both thermodynamic calculations and experiments closely reproduce paragenetic relations theoretically predicted by D.S. Korzhinskii in the 1940s.

关键词： High-grade metamorphismAlkali activityFluidsReaction texturesFluid-mineral reactionsThermodynamic modeling

Formation,characteristics and control of sludge in Al-containing magnesium alloys:An overview

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Journal of Magnesium and Alloys 2022年第3期10卷 643-658页

作者： y.Fu g.g.wang A.Hu y.Li K.B.Thacker J.P.Weiler H.Hu Department of Mechanical Automotive and Materials EngineeringUniversity of Windsor401 Sunset AveWindsorON N9B 3P4Canada global Technology Centre Meridian Lightweight Technologies25 MacNab AveStrathroyON N7G 4H6Canada

Sludge consisting of heavy element phases and oxides is often generated during the casting operation of aluminum(Al)and magnesium(Mg)*** the help of the well-established Sludge Factor(SF)formula,it is relatively easy to control the sludge generation in aluminum *** formation mechanisms and characteristics of sludge in die casting magnesium alloys are still *** ensure the production of high quality die cast components at a low cost,a full understanding of sludge in die casting Mg alloys and its proper control measures need to be developed,since excessive sludge formation affects deleteriously material and operation cost,and casting *** the present report,the formation,characteristics and control of Mg die-casting sludge,based on the established knowledge of sludge formation and sludge factor in Al die casting alloys,are *** work on characterization and assessment of sludge in die cast Mg alloys are *** principles for control of sludge in ingot production in association with die casting of Mg alloys are *** assessment of Mg oxide and intermetallics relevant to sludge formation in Mg alloys are highlighted.

关键词： Sludge Magnesium alloys Die casting Al-Mn(-Fe)intermetallics Magnesium oxide Microstructure characterization

Dissociative Chemisorption of an H2（v,j） Molecule on Rigid Ni （100） Surface： Dependence on Surface Topologies and Initial Rovibrational States of the Molecules

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Chinese Physics Letters 2005年第2期22卷 420-423页

作者： MeryemEvecen MustafaBǒyǚkata MehmetCivi ZiyaB.gǚvenc DepartmentofPhysics GaziUniversity06500AnkaraTurkey DepartmentofPhysics ErciyesUniversity66100YozgatTurkey DepartmentofElectronicandCommunicationEngineering CankayaUniversity06530AnkaraTurkey

The H-2(v,j)+Ni(100) collision system has been studied to understand theeffects of the surface sites and initial rovibrational states of the molecule on molecule-surfaceinteractions, by a quasiclassical molecular dynamic simulation method. Dissociative adsorption of anH-2 molecule on the rigid Ni(100) surface is investigated at topologically different three sites ofthe surface. Interaction between the molecule and Ni surface was described by a London-EyringPolani-Sato (LEPS) potential. Dissociative chemisorption probabilities of the H-2(v, j) molecule onvarious sites of the surface are presented as a function of the translation energies between0.001-1.0eV. The probabilities obtained at each collision site have unique behaviour. At lowercollision energies, indirect processes enhance the reactivity, effects of the rotational excitationsand impact sites on the reactivity are more pronounced. The results are compared with the availablestudies, The physical mechanisms underlying the results and quantum effects are discussed.

关键词： 6-DIMENSIONAL QUANTUM DyNAMICS ASSOCIATIVE DESORPTION ROTATIONAL MOTION ENERgy-DEPENDENCE NI(111) SURFACES NI CLUSTERS ADSORPTION CU(111) HyDROgEN SIMULATION