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Formation mechanism of interface reaction layer between microporous magnesia refractories and molten steel and its effect on steel cleanliness

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Journal of Iron and Steel Research(International) 2023年第9期30卷 1743-1754页

作者： Wen-wen Zhang Wan Zheng Wen Yan Guang-qiang Li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina Hubei Provincial Key Laboratory for New Process of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The ceramic filter in continuous casting tundish can effectively improve the cleanliness of high-performance steel by regulating tundish flow field to promote the removal of inclusions and adsorbing or blocking fine inclusions in the molten steel into the mold.The interaction between microporous magnesia refractories used as tundish filter and molten interstitial-free(IF)steel at 1873 K was investigated to reveal the Formation mechanism of their interface layer and its effect on steel cleanliness by laboratory research and thermodynamic calculations.The results show that the magnesium–aluminum spinel layer at the interface between the molten IF steel and the microporous magnesia refractories is formed mainly by the reaction of MgO in the refractory with the[Al]and[O]in the molten steel,significantly reducing the total O content,the size and amount of inclusions of the molten steel.In addition,the interparticle phases of microporous magnesia refractories at high temperature can adsorb Al_(2)O_(3) and TiO_(2) inclusions in the molten steel into interparticle channels of the refractories to form high melting point spinel,impeding the further penetration of the molten steel.As a result,the consecutive interface layer of high melting point spinel between microporous magnesia refractories and molten steel can improve the cleanliness of the molten steel by adsorbing inclusions in the molten steel and avoid the direct dissolution of refractories of the tundish ceramic filter immersed in the molten steel,increasing their service life.

关键词： Tundish metallurgy Microporous magnesia refractory Interstitial-free steel Formation mechanism Interface reaction layer Inclusion removal

Formation mechanism and control strategy for particulate nitrate in China

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Journal of Environmental Sciences 2023年第1期123卷 476-486页

作者： Haichao Wang Keding Lu Zhaofeng Tan Xiaorui Chen Yuhan Liu Yuanhang Zhang School of Atmospheric Sciences Sun Yat-sen UniversityGuangzhou 510275China State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China Institute of Energy and Climate Research IEK-8:TroposphereForschungszentrum Jülich GmbHJülich 52428Germany Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China China Institute of Atomic Energy Beijing 100193China

Over the past decade,fine particulate matter(PM)pollution in China has been abated significantly,benefiting from strict emission control measures,but particulate nitrate continues to rise.Here,we review the progress in particulate nitrate(p NO3-)pollution characterization,nitrate Formation mechanisms,and the proposed control strategies in China.The spatial and temporal distributions of p NO3-are summarized.The current status of knowledge on the chemical mechanism is updated,and the significance of its formation pathways is assessed by various approaches such as field observation and modelling of nitrate production rate,as well as isotopic analysis.The factors impacting p NO3-formation and the corresponding pollution regulation strategies are discussed,in which the importance of atmospheric oxidation capacity and ammonia are addressed.Finally,the challenges and open questions in p NO3-pollution control in China are outlined.

关键词： Particulate nitrate Reactive nitrogen Particulate matter Formation mechanism Air pollution control

Synthesis,Formation mechanism,and intrinsic physical properties of several As/P-containing MAX phases

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Journal of Materials Science & Technology 2023年第2期133卷 23-31页

作者： Hongxiang Chen Sheng Li Jun Deng Zhilong Zhang Jianeng Huang Fa Chang Li Huang Shixuan Du Pinqiang Dai School of Materials Science and Engineering Fujian University of TechnologyFuzhou 350118China Institute of Physics&University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100190China Fujian Provincial Key Laboratory of Advanced Materials Processing and Application Fuzhou 350118China Center for Advanced Energy and Functional Materials Fujian University of TechnologyFuzhou 350118China Songshan Lake Materials Laboratory Dongguan 523808China CAS Key Laboratory of Vacuum Physics Beijing 100049China

321 phases are an atypical series of MAX phases,in which A=As/P,with superior elastic properties,fea-turing in the MA-triangular-prism bilayers in the crystal structure.Until now,besides Nb 3 As 2 C,the pure phases of the other 321 compounds have not been realized,hampering the study of their intrinsic prop-erties.Here,molten-salt sintering(MSS)and solid-state synthesis(SSS)were applied to synthesize As/P-containing 321 phases and 211 phases.Analyzing the phase composition of the end-product via multiple-phase Rietveld refinement,we found that MSS can effectively improve the purity of P-containing MAX phases,with the phase content up to 99%in Nb_(3)P_(2)C and 75.4(5)%in Nb 2 PC.In contrast,MSS performed poorly on As-containing MAX phases,only 8.9(4)%for Nb 3 As 2 C and 64(2)%for Nb 2 AsC,as opposed to the pure phases obtained by SSS.The experimental analyses combined with first-principles calculations reveal that the dominant formation route of Nb_(3)P_(2)C is through NbP+Nb+C→Nb_(3)P_(2)C.Moreover,we found that the benefits of MSS on P-containing MAX phases are on the facilitation of three consid-ered chemical reaction routes,especially on Nb 2 PC+NbP→Nb_(3)P_(2)C.Furthermore,the intrinsic physical properties and Fermi surface topology of two 321 phases consisting of electron,hole,and open orbits are revealed theoretically and experimentally,in which the electron carriers are dominant in electrical trans-port.The feasible synthesis methods and the Formation mechanism are instructive to obtain high-purity As/P-containing MAX phases and explore new MAX phases.Meanwhile,the intrinsic physical properties will give great support for future applications on 321 phases.

关键词： MAX phase Molten-salt synthesis Chemical reaction route Metallic ceramics Formation mechanism Quasi-harmonic approximation

Microstructure evolution and Formation mechanism of CoCrCu1.2FeNi high entropy alloy during the whole process of semi-solid billet preparation

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Journal of Materials Science & Technology 2022年第25期120卷 172-185页

作者： Jufu Jiang Minjie Huang Ying Wang Yingze Liu Ying Zhang School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Mechatronics Engineering Harbin Institute of TechnologyHarbin 150001China

Dual face-centered cubic(FCC)CoCrCuFeNi semi-solid billets were prepared by semisolid isothermal treatment of wrought high entropy alloy(HEA)(SSITWH)method,and the microstructure evolution in the whole process of billets preparation was systematically investigated by optical microscopy,scanning electron microscopy,electron backscatter diffraction and transmission electron microscopy.The hot deformed feedstock was mainly composed of deformation structure with preferred orientations and a small number of dynamically recrystallized grains of FCC1 phase.In the semi-solid stage,the effect of temperature and soaking time on semi-solid microstructure was studied in the range of 1130-1250℃and 5-120 min.The semi-solid microstructure was evaluated quantitatively.The average grain size and average shape factor increased with the increase of soaking time and isothermal temperature.After isothermal heat treatment,the segregation of Cu in FCCphase reduced to a certain extent.Semi-solid coarsening kinetics analysis showed that the alloy had low coarsening coefficients.When the temperatures were1130℃,1175℃,1200℃,1225℃and 1250℃,the coarsening coefficients were 1.08μm~3/s,5.95μm~3/s,6.17μm~3/s,17.58μm~3/s,38.67μm~3/s,respectively.A coarsening kinetic equation describing solid grain growth was established.During heating up,FCCand FCCphase recrystallized successively.At higher temperature,FCCphase was spheroidized to a certain extent.When temperature was raised to semisolid range,the grains of FCCphase coalesced,grew up and spheroidized and the preferred orientations basically disappeared.The types of semi-solid melting characteristics of HEAs were summarized in this paper.The semi-solid melting behavior of alloys is essentially affected by phase structure,phase number,phase volume content and composition.

关键词： High entropy alloy Semi-solid billets Microstructure Grain coarsening Formation mechanism

Formation mechanism of Ground Fissures Originated from the Hanging Wall of Normal Fault:A Case in Fen-Wei Basin,China

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Journal of Earth Science 2022年第2期33卷 482-492页

作者： Zhijie Jia Jianbing Peng Quanzhong Lu Jianwei Qiao Feiyong Wang Mingdong Zang Yang Liu Junyan Zhao Fengji Zhu School of Geological Engineering and Geomatics Chang an UniversityXi'an 710054China Key Laboratory of Western Mineral Resources and Geological Engineering Ministry of Education Chang'an UniversityXfan 710064China China JK Institute of Engineering and Design Xfan 710043China Shaanxi Key Laboratory for the Property and Treatment of Special Soil and Rock Xfan 710043China School of Engineering and Technology China University of GeosciencesBeijing 100083China

This paper takes Fen-Wei Basin(FWB)as a case to study the ground fissures controlled by normal fault.Based on the field investigation,geophysical exploration,drilling,GNSS data and numerical calculation,the characteristics and mechanism of ground fissures originated from the hanging wall of normal faults are revealed.The results show that the distribution of ground fissures in the hanging wall and heading wall of the active faults is not uniform.Ground fissures are mostly distributed in the hanging wall of active faults and show a linear distribution on the surface,their strike is consistent with the fault,mainly characterized by vertical offset and horizontal tension.Ground fissures destroy the farmland and building foundation through which they pass and cause the rupture or displacement.In profile section,the ground fissure shows the characteristics of normal faults and dislocates the strata,and is connected with the underlying faults.Numerical analysis shows that the vertical displacement of normal fault activity in hanging wall is much larger than that in heading wall,which is the reason that tectonic ground fissures mainly originate from hanging wall.The range of dangerous area of ground fissures is controlled by the depth of fault,the strength of the ground fissures disaster is mainly controlled by the activity of fault.The formation of the ground fissures originated from the hanging wall of the fault experienced three stages:the main fault activity stage,the secondary fault activity stage and the fissure formation stage.

关键词： ground fissure Fen-Wei Basin active fault dislocation theory Formation mechanism hazards engineering geology

Formation mechanism and modeling of surface waviness in incremental sheet forming

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Frontiers of Mechanical Engineering 2022年第2期17卷 129-143页

作者： Kai HAN Xiaoqiang LI Yanle LI Peng XU Yong LI Qing LI Dongsheng LI School of Mechanical Engineering and Automation Beihang UniversityBeijing 100083China Beijing Institute of Aeronautical Materials Beijing 100095China School of Mechanical Engineering Shandong UniversityJinan 250061China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of EducationJinan 250061China Materials Science Branch of Chinalco Research Institute Chinalco Materials Application Research Institute Co.Ltd.Beijing 102209China

mproving and controlling surface quality has always been a challenge for incremental sheet forming (ISF), whereas the generation mechanism of waviness surface is still unknown, which impedes the widely application of ISF in the industrial field. In this paper, the Formation mechanism and the prediction of waviness are both investigated through experiments, numerical simulation, and theoretical analysis. Based on a verified finite element model, the waviness topography is predicted numerically for the first time, and its generation is attributed to the residual bending deformation through deformation history analysis. For more efficient engineering application, a theoretical model for waviness height is proposed based on the generation mechanism, using a modified strain function considering deformation modes. This work is favorable for the perfection of Formation mechanism and control of surface quality in ISF.

关键词： surface waviness incremental sheet forming numerical simulation Formation mechanism deformation history

Formation mechanism,experimental method,and property characterization of graindisplacing methane hydrates in marine sediment:A review

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China Geology 2022年第2期5卷 345-354页

作者： Yong-chao Zhang Le-le Liu Gao-wei Hu Qing-tao Bu Cheng-feng Li Zheng-cai Zhang Jian-ye Sun Chang-ling Liu The Key Laboratory of Gas Hydrate Qingdao Institute of Marine GeologyChina Geological SurveyMinistry of Natural ResourcesQingdao 266237China Laboratory for Marine Mineral Resources Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China

Grain-displacing hydrate deposits exist at many marine sites,which constitute an important part of methane hydrate resources worldwide.Attributed to the difficulties in acquiring field data and synthesizing experimental samples,the formation and property characterization of grain-displacing hydrate remains less understood and characterized than the pore-filling hydrate in current literature.This study reviews the Formation mechanisms of grain-displacing hydrate from the perspective of geological accumulation and microscale sedimentary property.The experimental methods of synthesizing grain-displacing hydrate in the laboratory and the current knowledge on the property of grain-displacing hydrate sediment are also introduced.Shortcomings in current theories and suggestions for future study are proposed.The work is hoped to provide valuable insights for the research into the hydrate accumulation,geophysics,and hydrate exploitation targeted at the grain-displacing hydrate in the marine sediments.

关键词： Methane hydrates Formation mechanism Grain-displacing hydrate Pore-filling hydrate Synthesis method Sedimentary property Oil and gas exploration engineering NGHs exploration trial engineering

Distribution control and Formation mechanism of gas inclusions in directionally solidified Al2O3-Er3Al5O12-ZrO2 ternary eutectic ceramic by laser floating zone melting

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Journal of Materials Science & Technology 2021年第7期66卷 21-27页

作者： Haijun Su Yuan Liu Qun Ren Zhonglin Shen Haifang Liu Di Zhao Guangrao Fan Min Guo Jun Zhang Lin Liu Hengzhi Fu Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518057China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an710072China

Distribution control and Formation mechanism of gas inclusions formed in directionally solidified Al2O3-Er3Al5O12-ZrO2 eutectic ceramic rods are explored during laser floating zone melting. In atmospheric environment, highly-dense bubble-free eutectic rods are well fabricated at low solidification rate(Formation mechanism of gas inclusions.

关键词： Directional solidification Gas inclusions Eutectic oxide Laser floating zone melting Formation mechanism

Formation mechanism of surface oxide layer of grain-oriented silicon steel

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Journal of Iron and Steel Research(International) 2021年第3期28卷 327-334页

作者： Jia-long Qiao Fei-hu Guo Sheng-tao Qiu Xing-zhong Zhang Hai-jun Wang National Engineering Research Center of Continuous Casting Technology China Iron&Steel Research Institute GroupBeijing100081China School of Metallurgy and Resources Anhui University of TechnologyMa’anshan243002AnhuiChina

The surface oxide layer of grain-oriented electrical steels was investigated by scanning electron microscopy.The Formation mechanism and the influence on the glass film of the surface oxide layer were analyzed by the calculation of thermodynamics and kinetics.The surface oxide layer with 2.3μm in thickness is mainly composed of SiO_(2),a small amount of FeO and Fe_(2)SiO_(4).During the formation of surface oxide layer,the restriction factor was the diffusion of O in the oxide layer.At the initial stage of the decarburization annealing,FeO would be formed on the surface layer.SiO_(2) and silicate particles rapidly nucleated,grew and formed a granular oxide layer in the subsurface.As the oxidation layer thickens,the nucleation of new particles decreases,and the growth of oxide particles would be dominant.A lamellar oxide layer was formed between the surface oxide layer and the steel matrix,and eventually formed a typical three-layer structure.During the high temperature annealing,MgO mainly reacted with SiO_(2) and Fe_(2)SiO_(4) in the surface oxide layer to form Mg2SiO_(4) and Fe_(2)SiO_(4) would respond first,thus forming the glass film with average thickness of 4.87μm.

关键词： Grain-oriented silicon steel Decarburizing annealing Surface oxide layer Formation mechanism Glass film