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Effects of Forging and Heat Treatments on the Microstructure and Oxidation Behavior of 316LN Stainless Steel in High Temperature Water

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Journal of Materials Science & Technology 2015年第4期31卷 403-412页

作者： Yueling Guo en-Hou Han Jianqiu Wang National Center for Materials Service Safety University of Science and Technology Beijing Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of Science

Microstructure of 316 LN stainless steel(ss),including the as-received material and samples processed by solution anneal treatment and stress relief treatment after forging,was characterized by Vickers hardness(HV) testing and electron back scattering diffraction(EBSD).The oxide film formed on samples after immersion in borated and lithiated water at 583.15 K was investigated by scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS).Results showed that the grain size of samples was largely reduced after *** fraction of coincidence site lattice(CSL) boundaries and lower residual strain were observed in samples with either solution anneal treatment or stress relief *** proportion of CSL boundaries was largely enhanced by solution anneal treatment after forging,due to the recrystallization occurring during solution anneal *** oxide film grown on 316 LNss with solution anneal treatment after forging exhibited more strong protectiveness,as compared to the oxide film grown on samples with stress relief treatment after forging and the oxide film grown on asreceived samples without *** mechanisms of oxidation were then discussed.

关键词： Stainless steel Forging Corrosion Residual strain

Pitting corrosion of a Rare Earth Mg alloy GW93

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Journal of Materials Science & Technology 2017年第9期33卷 954-960页

作者： Yingwei Song Dayong Shan en-Hou Han Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of Sciences

Pitting corrosion of magnesium(Mg) alloys is greatly associated with their microstructure, especially second phases. The second phases in traditional Mg alloys such as AZ91 are electrochemically nobler than Mg matrix, while the second phases in Rare earth(RE) Mg alloy GW93 are more active than Mg matrix. As a result, the pitting corrosion mechanism of Mg alloy GW93 is different from the traditional ones. This paper aims to clarify the pitting corrosion mechanism of Mg alloy GW93 through the studies of Volta potential by Scanning Kelvin Probe Force Microscopy(SKPFM), corrosion morphology by Scanning Electron Microscope(SEM), and corrosion resistance by electrochemical tests. Results reveal that the pitting corrosion of GW93 includes three stages, first, dissolution of the second phases, followed by corrosion of Mg matrix adjacent to the dissolved second phases, and finally, propagation of corrosion pits along the depth direction of the dissolved second phases. Anodic second phases and enrichment of Clin the thick corrosion product films dominate the propagation of pitting corrosion.

关键词： Mg alloys Pitting corrosion Second phases Oxide films

Lsyn-Esyn,p-δrelation in active galactic nucleus jets and implication for the physical origin of the Lp-Ep,z-Γ_0 relation of gamma-ray bursts

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Research in Astronomy and Astrophysics 2020年第9期20卷 201-209页

作者： Xiao-Li Huang en-Wei Liang School of Astronomy and Space Science Nanjing UniversityNanjing 210023China Guangxi Key Laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China

High energy photon radiations of gamma-ray bursts(GRBs)and active galactic nuclei(AGNs)are dominated by their jet *** examine whether the synchrotron radiations of jets in BL Lacs,flat spectrum radio quasars(FSRQs),and Narrow Line Seyfert 1 galaxies(NLS1s)follow the relation between the prompt gamma-ray emission and the initial Lorentz factor(Γ0)of *** is shown that the AGN sample does not agree with the Lp-Ep,z-Γ0 relation of *** addition,we obtain a tight relation of Lsyn∝Е0.45±0.15δ3.50±0.25 syn,p for FSRQs and NLS1 galaxies,where Lsyn is the luminosity at peak photon energy Esyn,p of the synchrotron *** relation is different from the Lp-Ep,z-Γ0 relation of GRB *** dependence of Lsyn toδis consistent with the expectation of the Doppler boosting effect for the FSRQs and NLS1 galaxies,but it is not for *** argue thatΓ0 may be a representative of the kinetic power of the radiating region and the tight Lp-Ep,z-Γ0 relation is shaped by the radiation physics and the jet power together.

关键词： gamma-ray burst:general quasars:general BL Lacertae objects:general galaxies:Seyfert stars:jets radiation mechanisms:non-thermal

Effect of tannic acid on corrosion behavior of carbon steel in NaCl solution

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Journal of Materials Science & Technology 2019年第1期35卷 64-75页

作者： Wenhua Xu en-Hou Han Zhenyu Wang Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences University of Chinese Academy of Sciences

Corrosion behavior of unrusted Q235 carbon steel was investigated in 3.5% NaCl solutions with 1–5 wt%tannic acid addition, using electrochemical methods including electrochemical impedance spectra(EIS),potentiodynamic polarization and scanning vibrating electrode technique(SVET) combined with surface analysis. Results show that the corrosion rate decreases with increasing tannic acid concentration. As compared with tannic acid-free solution, 1% tannic acid does not provide inhibition effect during the whole immersion, while inhibition effect is observed for 3% tannic acid after 8 h and for 5% tannic acid after 4 h. The inhibition efficiency by weight loss measurements(áw) for 1%, 3%, and 5% tannic is around-17.2%, 40.3%, and 51.5%, respectively. Corrosion of unrusted carbon steel in the presence of tannic acid is attributed to the joint effect of tannic acid adsorption and pH decrease. Formation of ferric-tannates is verified by X-ray photoelectron spectroscopy(XPS) and Raman spectra. The reaction mechanism between tannic acid and unrusted carbon steel is proposed.

关键词： Tannic acid Unrusted carbon steel Ferric-tannates EIS Corrosion

Behavior of molten steel flow in continuous casting mold with different static magnetic field configurations

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Journal of Iron and Steel Research International 2018年第4期25卷 366-377页

作者： Zhuang Li en-gang Wang Yu Xu Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education) Northeastern University Shenyang 110004 Liaoning China School of Materials Science and engineering Northeastern University Shenyang 110004 Liaoning China School of Metallurgy Northeastern University Sheuyang 110004 Liaoning China

A three-dimensional mathematical model was established to investigate the behavior of molten steel flow and steel/slag interface with different processes and electromagnetic parameters under two different static magnetic field configurations [ruler-type electromagnetic brake （EMBr ruler） and vertical electromagnetic brake （V-EMBr）] in a continuous casting mold. The results showed that the brake effect of EMBr ruler is significantly influenced by its configuration parameters, the distance between the pole and bottom of the submerged entry nozzle （Sen）, and the port angle of the Sen outlet; therefore, it is not helpful to depress the diffusion of jet flow along the thickness direction of mold. For a constant Sen depth and port angle, there is a reasonable pole position （P = 0 mm） where the pole simultaneously covers three key zones, i.e., the jet flow impact zone and the upward and downward backflow zones. For V-EMBr, the magnetic field can simultaneously cover the three key zones and depress the diffusion of jet flow along the casting and thickness directions of the mold. Both the meniscus height and the impact intensity of the jet flow can be obviously depressed by V-EMBr even if the Sen depth and port angle have changed in the continuous casting process.

关键词： Static magnetic field Continuous casting Mold Electromagnetic brake ruler Vertical electromagneticbrake Molten steel flow

Multi-stimuli-triggered and self-repairable fluorocarbon organic coatings with urea-formaldehyde microcapsules filled with fluorosilane

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Journal of Materials Science & Technology 2020年第10期42卷 70-83页

作者： Paul CUzoma Fuchun Liu en-Hou Han Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and engineering University of Science and Technology of ChinaHefei230026China Shenyang Zhongke engineering Technology Center for Corrosion Control Shenyang110016China Department of Polymer and Textile engineering Federal University of TechnologyP.M.B.1526OwerriNigeria

For the purpose of overcoming the lack of durability problems associated with superhydrophobic surfaces which hitherto has limited their use;we prepared multi-stimuli wettability response coatings using a mixture of fluorocarbon resin and urea-formaldehyde microcapsules filled with fluorosilane via interfacial polymerization *** microcapsules are of good thermal stability and can be triggered to release their core content on exposure to atmospheric conditions resulting in the increase in the water contact angle from 97°to 151°.The prepared coatings gave good adhesion strength,and also showed an increase in the hydrophobic property after undergoing scratch,solvent and UV accelerated aging *** addition,they offered good self-healing of the hydrophobic property after an initial loss due to alkaline immersion and oxygen plasma *** electrochemical measurements revealed a remarkable impedance recovery and suppression of corrosion activities,suggesting them to be a potential candidate material for corrosion protection.

关键词： Multi-stimuli Microcapsules Superhydrophobic Self-healing Coatings Anti-corrosion

Modeling and identification of magnetostrictive hysteresis with a modified rate-independent Prandtl-Ishlinskii model

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Chinese Physics B 2018年第9期27卷 626-634页

作者： Wei Wang Jun-en Yao School of Instrumentation Science and Opto-electronics engineering Beihang UniversityBeijing 100083China School of Physics and Nuclear energy engineering Beihang UniversityBeijing 100083China Laboratory of Micro-nano Measurement Manipulation and PhysicsBeihang UniversityBeijing 100083China

This paper presents a modified rate-independent Prandtl-Ishlinskii （MRIPI） model based on the Fermi-Dirac distri- bution for the asymmetric hysteresis description of magnetostrictive actuators. Generally, the classical Prandtl-Ishlinskii （CPI） model can hardly describe the asymmetric hysteresis. To overcome this limitation, various complex operators have been developed to replace the classical operator. In this study, the proposed MRIPI model maintains the classical operator while a modified input function based on the Fermi-Dirac distribution is presented to replace the classical input function. With this method, the MRIPI model can describe the asymmetric hysteresis of magnetostrictive actuators in a relatively simple mathematic format and has fewer parameters to be identified. A velocity-based sine cosine algorithm （VSCA） is also proposed for the parameter identification of the MRIPI model. To verify the validity of the MRIPI model, experiments are performed and the results are compared with those of the existing modeling methods.

关键词： Prandtl-Ishlinskii model velocity-based sine cosine algorithm asymmetric hysteresis nonlinear-ity magnetostrictive actuator

Acoustoelastic effects on mode waves in a fluid-filled pressurized borehole in triaxially stressed formations

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Acta Mechanica Sinica 2006年第6期22卷 569-580页

作者： Ping'en Li Youquan Yin Xianyue Su LTCS Department of Mechanics and Aerospace Engineering College of Engineering Peking University Beijing 100871 China

Based on the nonlinear theory of acoustoelasticity, considering the triaxial terrestrial stress, the fluid static pressure in the borehole and the fluid nonlinear effect jointly, the dispersion curves of the monopole Stoneley wave and dipole flexural wave prop- agating along the borehole axis in a homogeneous isotropic formation are investigated by using the perturbation method. The relation of the sensitivity coefficient and the velocity-stress coefficient to frequency are also analyzed. The results show that variations of the phase velocity dispersion curve are mainly affected by three sensitivity coefficients related to third-order elastic constant. The borehole stress concentration causes a split of the flexural waves and an intersection of the dispersion curves of the flexural waves polarized in directions parallel and normal to the uniaxial horizontal stress direction. The stress-induced formation anisotropy is only dependent on the horizontal deviatoric terrestrial stress and independent of the horizontal mean terrestrial stress, the superimposed stress and the fluid static pressure. The horizontal terrestrial stress ratio ranging from 0 to 1 reduces the stress-induced formation anisotropy. This makes the intersection of flexural wave dispersion curves not distinguishable. The effect of the fluid nonlinearity on the dispersion curve of the mode wave is small and can be ignored.

关键词： Triaxial terrestrial stress Borehole fluid pressure Fluid nonlinear effect Acoustoelasticity Dispersion curve crossover

Characteristics of Oxidation and Oxygen Penetration of Alloy 690 in 600°C Aerated Supercritical Water

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Journal of Materials Science & Technology 2018年第3期34卷 561-569页

作者： Xiangyu Zhong Xinqiang Wu en-Hou Han CAS Key Laboratory of Nuclear Materials and Safety Assessment Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear MaterialsInstitute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The oxide films formed on Alloy 690 exposed to 600 ℃ supercritical water were characterized using mass measurement, X-ray diffraction. Raman spectroscopy, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. It was found that the mass gain of the alloy in supercritical water decreased with increasing exposure time. The oxide films have a double-layer structure, with an inner layer rich in Cr and outer layer rich in Ni and Fe after short time and long time exposure. The penetration of the oxide along the grain boundaries was observed, and the penetration depth increased with increasing exposure time. The grain boundaries and voids are the short-path of oxygen diffusion into the metal.

关键词： Ni-based alloy XPS Supercritical water High temperature corrosion High temperature oxidation Oxide film