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PREDICTION OF CARBON CONCENTRATION AND FERRITE VOLUME FRACTION OF HOT-ROLLED STEEL STRIP DURINg LAMINAR COOLINg

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Acta Metallurgica Sinica(English Letters) 2007年第4期20卷 251-257页

作者： Y.T. zhang C.z. Wang D.z. Li Y.Y. Li School of Material Science and Engineering Shenyang Ligong University Shenyang 110168 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

A phase transformation model was presented for predicting the phase fraction transformed and the carbon concentration in austenite for austenite to ferrite transformation during laminar cooling on run-out table in hot rolling strip mill. In this model, the parameter k in Avrami equation was developed for carbon steels. The wide range of chemical composition, the primary austenite grain size, and the retained strain were taken into account. It can be used to predict the ferrite volume fraction and the carbon concentration in austenite of hot-rolled steel strip during laminar cooling on run-out table. The coiling temperature controlling model was also presented to calculate the temperature of steel strip. The transformation kinetics of austenite to ferrite and the evolution of carbon concentration in austenite at different temperatures during cooling were investigated in the hot rolled Q235B strip for thickness of 9.35, 6.4, and 3.2mm. The ferrite volume fraction along the length of the strip was also calculated. The calculated ferrite volume fraction was compared with the log data from hot strip mill and the calculated results were in agreement with the experimental ones. The present study is a part of the prediction of the mechanical properties of hot-rolled steel strip, and it has already been used on-line and off-line in the hot strip mill.

关键词： carbon concentration ferrite volume fraction laminar cooling hot rolling

Enhanced pitting corrosion resistance of a zr-based metallic glass by ultraviolet light irradiation

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Journal of Iron and Steel Research International 2023年第8期30卷 1642-1649页

作者： z.Chen D.P.Wang S.Wang Y.X.geng Y.X.guo Y.C.Wu z.g.Liu Y.Y.zhang Y.X.Wang School of Materials Science and Engineering Jiangsu University of Science and Technology.Zhenjiang 212003JiangsuChina School of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003JiangsuChina

The influence of ultraviolet light irradiation on the pitting corrosion performance of a zr_(2)Ni metallic glass was examined using electrochemical methods and immersion test in 0.05 mol/L NaCl *** the results of potentiostatic polarization,the pitting potential of the ultraviolet light-irradiated sample shifted positively with a value of~300 mV,revealing the enhanced pitting corrosion resistance of the *** corrosion morphology after the immersion test also demonstrated lower degree of corrosion damage and improved pitting resistance of the sample with ultraviolet light irradiation.X-ray photoelectron spectroscopy analysis revealed more zirconium enrichment in the passive film and no chloride ions adsorption for the samples with ultraviolet irradiation,accounting for the suppression of the pit generation and *** findings indicate that ultraviolet light irradiation improves the pitting corrosion resistance of the zr-based metallic glasses,which are promising structural materials to be used in corrosion environments with high ultraviolet irradiation.

关键词： Metallic glass Pitting-Corrosion Ultraviolet light irradiation Passive film

EFFECTS OF Ce ON CORROSION RESISTANCE OF Az91D MAgNESIUM ALLOY

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维普期刊数据库

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Acta Metallurgica Sinica(English Letters) 2005年第2期18卷 129-136页

作者： z.H.Huang X.F.guo z.M.zhang C.J.Xu SchoolofMaterialsScienceandEngineering Xi＇anUniversityofTechnologyXi＇an710048China

As-cast and corrosive microstructures of Az91D alloy containing various Ce contents were observed by optical microscope (OM). The phase compositions of the alloys before and after the corrosion were analyzed by X-ray diffraction (XRD). Meanwhile, the corrosion resistance of the alloys was tested by weight loss and potentiodynamic polarization curve methods respectively. The results show that rod-like Al4Ce phase is formed in Az91D alloy containing certain Ce content and as-cast microstructures are refined. Az91D-0.7%Ce alloy has good grain refinement effect. The addition of Ce can reduce the corrosion rate and corrosion current density of Az91D alloy and those of Az91D-0.1%Ce alloy reach the minimum, which are 0.35mg/(cm2·d) and 2.761μA/cm2 with 75% and 86% reduction, respectively. The increasing volume fraction and reticular degree of β phase can improve the corrosion resistance of the alloys.

关键词： Az91D magnesium alloy Ce modification microstructure corrosion resistance

RECIPROCATINg EXTRUSION OF IN SITU Mg_2Si REINFORCED Mg-Al BASED COMPOSITE

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Acta Metallurgica Sinica(English Letters) 2008年第3期21卷 169-177页

作者： z.M. zhang C.J. Xu X.F. guo S.z. Jia School of Materials Science ＆ Engineering Xi＇an University of Technology Xi＇an 710048 China

M92Si reinforced Mg-Al based composite with high amount o/silicon was prepared by permanent mould casting, and then extruded by reciprocating extrusion （RE） after the composite was processed by homogenization heat treatment. The effect of RE processing on the morphology and size of M92Si and the mechanical properties of the com- posite were investigated, to develop new ways to refine the M928i phase and improve its shape. The result showed that RE was very useful in refining the M92Si phase. The more the RE processing passes, the better the refining effect would be. Moreover, the uniform distribution of M928i phases would be more in the composite. After the composite was processed by RE for 12 passes, most M92Si phases were equiaxed, with granular diameter below 20 μm, and distributed uniformly in the matrix of the composite. The mechanical properties of the composite could be increased prominently by RE processing, and were much higher than that in the as-cast state. As the temperature rises, the tensile strength is reduced. For the composite RE processed for 12 passes, the tensile strength, yield strength, and elongation are 325.9 MPa, 211.4 MPa, and 3.3% at room temperature, whereas, 288.2 MPa, ,207.7 MPa, and 7.8%, respectively, at 150℃. In comparison with the properties at room temperature, the tensile strength and yield strength are high and only decrease by 11.6% and 1.8% at 150℃. The M928i reinforced Mg-Al based composite possesses good heat resistance at 150℃. The excellent resistance to effect of heat is attributed to the high melting tempera- ture and good thermal stability of fine Mg2Si phases, which are distributed uniformly in the composite, and effectively hinder the grain boundary gliding and dislocation movement.

关键词： Reciprocating extrusion Magnesium alloy In situ composite Elevated temperature property

Design and Pilot Programs of Marine Exposure Station of A Sea-crossing Bridge

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武汉理工大学学报 2010年第17期32卷 131-136页

作者： QIN M Q WANg C J TU L Q zhang g z SUN T X Wuhan Harbour Engineering Design and Research Co. Ltd. Wuhan 430071China Key Lab of Large-span Bridge Construction Technology Ministry of CommunicationsWuhan 430071China zhejiang Province zhoushan Island Linking Construction Commanding Department Zhoushan 316032China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

This paper presents the Location,the structural design as well as the anti-corrosion and the pilot programs of the marine exposure station of zhoushan Archipelago seas sea-crossing bridges. Subjected to the marine environment,the concrete structures in serve with different mixing proportions,cover thickness,additional anti-corrosion measures such as rust-preventing agent,coating,penetration crystalline waterproof material,silicone and permeable fabric were studied. Those results obtained provide important information for the maintenance of marine concrete and the structural design of sea-crossing bridges in the above sea area.

关键词： exposure station sea-crossing bridge marine concrete durability design

Boosted activity of Cu/SiO_(2) catalyst for furfural hydrogenation by freeze drying

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Chinese Chemical Letters 2022年第2期33卷 912-915页

作者： Hong Du Xiuyun Ma Miao Jiang z.Conrad zhang Dalian National Laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

The biomass valorization is of great importance as an alternative for the production of transport fuels and fine *** hydrogenation to furfuryl alcohol is a prevailing industrial route for the utilization of hemicellulose component of *** toxicity of the chromium species in commercial copper chromite catalyst for furfuryl alcohol production motivates the development of efficient chromium-free ***,a highly efficient silica supported copper catalyst is developed in this *** catalyst is prepared by freeze drying of a gel precursor that is synthesized by ammonia evaporation,followed by calcination and H_(2)*** catalyst exhibits higher furfural hydrogenation activity than oven dried catalyst,commercial copper chromite catalyst and a plant supplied commercial silica supported copper *** catalyst also shows good *** superior performance of the freeze dried catalyst has resulted from its developed pore structure and higher amount of Cu^(0)as well as Cu^(+)active sites.

关键词： Freeze drying Cu/SiO_(2) Furfural Furfuryl alcohol Hydrogenation

Exploring the Spatial Control of Topotactic Phase Transitions Using Vertically Oriented Epitaxial Interfaces

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Nano-Micro Letters 2022年第1期14卷 47-58页

作者： Wenrui zhang Jie zhang Shaobo Cheng Christopher M.Rouleau Kim Kisslinger Lihua zhang Yimei zhu Thomas z.Ward gyula Eres Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingboZhejiang 315201P.R.China Condensed Matter Physics and Materials Science Brookhaven National LaboratoryUptonNY 11973USA Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37831USA Center for Functional Nanomaterials Brookhaven National LaboratoryUptonNY 11973USA

Engineering oxygen vacancy formation and distribution is a powerful route for controlling the oxygen sublattice evolution that affects diverse functional *** controlling of the oxygen vacancy formation process is particularly important for inducing topotactic phase transitions that occur by transformation of the oxygen *** we demonstrate an epitaxial nanocomposite approach for exploring the spatial control of topotactic phase transition from a pristine perovskite phase to an oxygen vacancy-ordered brownmillerite(BM)phase in a model oxide La_(0.7)Sr_(0.3)MnO_(3)(LSMO).Incorporating a minority phase NiO in LSMO films creates ultrahigh density of vertically aligned epitaxial interfaces that strongly influence the oxygen vacancy formation and distribution in *** structural characterizations reveal strong interactions between NiO and LSMO across the epitaxial interfaces leading to a topotactic phase transition in LSMO accompanied by significant morphology evolution in *** the NiO nominal ratio as a single control parameter,we obtain intermediate topotactic nanostructures with distinct distribution of the transformed LSMO-BM phase,which enables systematic tuning of magnetic and electrical transport *** use of self-assembled heterostructure interfaces by the epitaxial nanocomposite platform enables more versatile design of topotactic phase structures and correlated functionalities that are sensitive to oxygen vacancies.

关键词： Epitaxial interface Nanocomposite Functional oxides Oxygen vacancy Topotactic phase transition

Intrinsic Strength Asymmetry Between Tension and Compression of Perfect Face-Centered-Cubic Crystals

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Acta Metallurgica Sinica(English Letters) 2016年第8期29卷 755-762页

作者： R.F.Wang J.Xu R.T.Qu z.Q.Liu z.F.zhang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

The strength asymmetry between tension and compression is a typical case of mechanical response of *** we achieve the intrinsic strength asymmetry of six face-centered-cubic perfect crystals（Cu,Au,Ni,Pt,Al and Ir）through calculating the ideal tensile and compressive strength with considering the normal stress effect and the competition between different crystallographic *** results show that both the intrinsic factors（the ideal shear strength and cleavage strength of low-index planes）and the orientation could affect the strength asymmetry,which may provide insights into understanding the strength of ultra-strong materials.

关键词： Perfect crystal Strength asymmetry Tension Compression

Effect of post weld artificial aging and water cooling on microstructure and mechanical properties of friction stir welded 2198-T8 Al-Li joints

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Journal of Materials Science & Technology 2022年第28期123卷 92-112页

作者： Y.Tao z.zhang P.Xue D.R.Ni B.L.Xiao z.Y.Ma Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

Friction stir welding(FSW)under both air cooling and water cooling conditions with welding parameters of 800-1200 rpm rotation rates and 50-200 mm/min welding speeds was carried out on 2198-T8 Al-Li alloys,and post weld artificial aging was performed on the air cooled *** welding defects other than lazy S were observed in the nugget zone(Nz)for all *** air cooling condition,the lowest hardness zone(LHz)occurred in the heat affected zone(HAz).FSW resulted in gradual dissolution of original T_(1),θ′andδ′/β′from the base material(BM)to the thermo-mechanically affected zone(TMAz),and complete dissolution of all precipitates in the Nz withδ′/β′and guinier-Preston zones precipitating during *** air cooled joints exhibited no noticeable changes in intrinsic tensile strength with a joint strength reaching 81.3%of the BM,but varied elongation with welding parameters,which was closely related to failure in the Nz and fracture along lazy *** weld artificial aging led to the largest hardness recovery in the TMAz but smaller hardness recovery in the initial LHz and the *** aging kinetics across the joint was determined by volume fraction of both original precipitate dissolu-tion during welding and coarse particles formed during aging,and by dislocation density inherited from *** weld artificial aging greatly enhanced the joint strength with the ultimate tensile strength reaching 87.3%of the *** compared to air cooling condition,water cooling hardly affected the Nz hardness and did not improve the joint strength,and the reason was discussed in light of precipitates,hardness changes and fracture behavior.

关键词： Friction stir welding Aluminum-lithium alloys Microstructure Mechanical properties