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Long-term thermal-aging stability of oxide-dispersion-strengthened ferritic steels at 753 K

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Journal of Iron and Steel Research International 2018年第7期25卷 776-784页

作者： Shuai Xu zhang-jian zhou Shao-fu Li Hao-dong Jia School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Oxide-dispersion-strengthened （ODS） ferritic steels are promising candidates for structural applications in the future nuclear reactors. The higher chromium contents of ODS ferritic steels, the better the corrosion resistance, which can meet the harsh corrosion environment of the advanced reactors. However, increasing the Cr content may also lead to the brittleness of the ODS steels when serving at high temperatures. The ODS ferritic steels with different Cr contents （12, 16 and 18 wt% Cr, respectively） were fabricated by mechanical alloying, hot isostatic pressing and forging. Mechanical properties and microstructure evolution of the ODS ferritic steels after aging at 753 K for 2000 h were investigated. It is found that both Vickers hardness and yield strength of 18%Cr ODS ferritic steel were strongly increased and the impact energy was decreased after aging at 753 K. In order to explore the reasons for changes in the mechanical properties, the fracture surfaces were characterized by scanning electron microscopy, and microstructures after aging were observed by transmission electron microscopy. The impact fracture of 18%Cr ODS ferritic steel belongs to quasi-cleavage facture, which is consistent with its very low impact energy. The grain size and dispersed oxide particles of different ODS steels are very stable. M23C6 carbide and M2C carbide were found in 12%Cr ODS steel and 16%Cr ODS steels, respectively.

关键词： Oxide-dispersion-strengthened ferritic steel Aging stability - Mechanical property Microstructure

Effect of Thermomechanical Parameters on Σ3~n Grain Boundaries and Grain Boundary Networks of a New Superaustenitic Stainless Steel

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Journal of Iron and Steel Research International 2014年第1期21卷 109-115页

作者： Hong-ying SUN zhang-jian zhou Man WANG Xiao LI School of Materials Science and Engineering University of Science and Technology Beijing Technology Center Anyang Iron and Steel Group Company Metallurgy Engineering Research Institute University of Science and Technology Beijing

Hot compression tests were conducted in a temperature range of 800--1100 ℃and strain rate range of 0. 1- 10 s^-1 using a Gleeble 3500 thermomechanical simulator to investigate the influence of hot deformation parameters （temperatures, strain rates and strains） on the grain boundary network evolution of a new grade Fe-Cr-Ni superaustenitic stainless steel. The results showed that a dominant effect of deformed temperature is ∑3^n （n = 0, 1, 2, 3） boundaries population increased with decreasing temperature, while they first increased and then reduced with in- creasing strain and strain rate. Interestingly, besides E3n （n = 1, 2, 3） twin grain boundaries, some El boundaries could interrupt grain boundaries network effectively, which enhance material performances. But they are scarcely re- ported. The misorientation of some segments LAGBs in the deformed microstructure （pancaked grains） increased and slid to high angle grain boundaries with increasing the fraction of reerystallized grains during hot deformation.

关键词： superaustenitic stainless steel thermomechanieal processing electron backscatter diffraction (EBSD) coincidence site lattice grain boundary grain boundary engineering

Microstructural evolution and mechanical properties of an Fe–18Ni–16Cr–4Al base alloy during aging at 950°C

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International Journal of Minerals,Metallurgy and Materials 2016年第3期23卷 314-322页

作者： Man Wang Yong-duo Sun Jing-kai Feng Rui-qian zhang Rui Tang zhang-jian zhou School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610041China

The development of Gen-IV nuclear systems and ultra-supercritical power plants proposes greater demands on structural materials used for key components. An Fe-18Ni-16Cr-4Al（316-base） alumina-forming austenitic steel was developed in our laboratory. Its micro- structural evolution and mechanical properties during aging at 950℃were investigated subsequently. Microstructural changes were charac- terized by scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy. Needle-shaped NiAI parti- cles begin to precipitate in austenite after ageing for 10 h, whereas round NiA1 particles in ferrite are coarsened during aging. Precipitates of NiAI with different shapes in different matrices result from differences in lattice misfits. The tensile plasticity increases by 32.4% after aging because of the improvement in the percentage of coincidence site lattice grain boundaries, whereas the tensile strength remains relatively high at approximately 790 MPa.

关键词： austenitic steel alumina aging precipitates mechanical properties microstructural evolution nuclear power plants

Effects of Solution Depletion and Segregation Oxidation on Morphology of Modified 310 Austenitic Stainless Steel

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Journal of Iron and Steel Research International 2016年第4期23卷 393-400页

作者： Hong-ying SUN Qiang HE zhang-jian zhou Man WANG Guang-ming zhang Shao-fu LI Key Laboratory of Key Functional Parts of Machine Anyang Institute of TechnologyAnyang 455002HenanChina School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China

The oxidation morphologies of modified 310 steel exposed in 900 and 1 100 ℃ air were investigated. A double layer morphology consisting of a （Cr, Mn）-rich outer layer and a fine Cr-rich inner layer was formed at 900℃. It was related to the breakaway oxidation induced by the Cr-depletion and the Mn-segregation in inner layer. Some Cr-rich oxides with amorphous state were formed along grain boundaries. And some new finer oxide grains, voids and Cr-rich precipitates were observed in spallation areas at 1 100℃. Correspondingly, the oxidation kinetic curve dropped with the spallation of scale and increased with the formation of some new oxide grains. It was caused by segregation of Cr and the transformation of oxides from Cr2O3 to the volatile oxides at elevated temperature. XRD analysis showed that the precipitates were mainly composed of CrO3. Segregation and depletion for solutions were also discussed by oxidation diffusion mechanisms.

关键词： austenitic stainless steel SEM morphology oxidation segregation element

A rhodamine derivative for Hg^(2+) -selective colorimetric and fluorescent sensing and its application to in vivo imaging

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Chinese Chemical Letters 2016年第6期27卷 813-816页

作者： Xue-Mei Li Rui-Rui Zhao Yu-Ling Wei Dan Yang zhang-jian zhou Jun-Feng zhang Ying zhou Department of Safety Evaluation Technology Center of China Tobacco Yunnan Industrial Co. Ltd. College of Chemical Science and Technology Yunnan University College of Chemistry and Chemical Engineering Yunnan Normal University

A rhodamine-based sensor has been developed for the detection of mercuric ions. The colorimetric and fluorescence responses, allowing naked-eye detections, are based on Hg^2＋-induced opening of the rhodamine spirocycle. Among all the testes ions, only Hg^2＋generated a significant fluorescence enhancement of up to 300-fold, with a bright yellow–green emission. This sensor was a low toxic compound, and was successfully applied in the in vivo imaging of Hg^2＋in Spill 2 cells and C. elegans. This approach provides a sensitive and accurate method for the estimation of Hg^2＋in environmental, tobacco and biological applications.

关键词： Chemsensor Mercury Rhodamine Colorimetric Fluorescence In vivo imaging

High heat loading performance of actively cooled W/Cu FGM-based components

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International Journal of Minerals,Metallurgy and Materials 2011年第4期18卷 467-471页

作者： zhang-jian zhou Jun Tan Dan-dan Qu Hua Li Young-jin yum Hyun-woo Lim School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Electronic Engineering Institute Hefei 230037 China School of Mechanical ＆ Automotive Engineering University of Ulsan Ulsan 680-749 Korea

A functionally graded material-based actively water-cooled tungsten-copper mockup with a dimension of 30 mm×30 mm×25 mm was designed and fabricated by infiltration-brazing *** thicknesses of the pure W layer and W/Cu graded layer were 2 and 3 mm,*** heat flux tests were performed on the mockup using an e-beam *** is no damage occurring on the joint after heat loading at 5 MW/*** temperature on the pure W surface is less than 500°C after irradiation for 100 s at 5 MW/m2,while the temperature on the brazing seam/copper surface is around 200°C.

关键词： tungsten copper functionally graded materials thermal load

High Energy Proton-Proton Elastic Scattering in the Pomeron Exchange Model

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Communications in Theoretical Physics 2002年第7期38卷 65-67页

作者： HU Zhao-Hui zhang jian zhou Li-Juan LIU Ji-Feng MA Wei-Xing Department of Information and Computing Science Guangxi University of Technology Liuzhou 545006 China Department of Physics Guangxi Normal University Guilin 541004 China Department of Information and Computing Science Guangxi University of Technology Liuzhou 545006 China Department of Physics Guangxi Normal University Guilin 541004 China Department of Information and Computing Science Guangxi University of Technology Liuzhou 545006 China Institute of High Energy Physics the Chinese Academy of Sciences Beijing 100039 China Institute of Theoretical Physics the Chinese Academy of Scie

We study high energy proton-proton elastic scattering in the framework of Pomeron exchange model. The cross section of the process are calculated without any free parameters. Our finding is that Pomeron exchange theory gives perfect fits to total cross section at the energy of√s higher than 10 GeV and to differential cross section at the momentum transfer [t] less than 1.5 GeV2. For total cross section at lower energy √s ＜ 10 GeV and differential cross section at larger momentum transfer region of |t| ＞ 1.5 GeV2, the Pomeron exchange theory needs to be improved.

关键词： proton-proton elastic scattering, Pomeron exchange, cross section

Plant Immunity Triggered by Microbial Molecular Signatures

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Molecular Plant 2010年第5期3卷 783-793页

作者： Jie zhang jian-Min zhou National Institute of Biological Sciences 7 Science Park Road Zhongguancun Life Science Park Changping District Beijing 102206 China

Pathogen/microbe-associated molecular patterns （PAMPs/MAMPs） are recognized by host cell surface- localized pattern-recognition receptors （PRRs） to activate plant immunity. PAMP-triggered immunity （PTI） constitutes the first layer of plant immunity that restricts pathogen proliferation. PTI signaling components often are targeted by various Pseudomonas syringae virulence effector proteins, resulting in diminished plant defenses and increased bacterial virulence. Some of the proteins targeted by pathogen effectors have evolved to sense the effector activity by associating with cytoplasmic immune receptors classically known as resistance proteins. This allows plants to activate a second layer of immunity termed effector-triggered immunity （ETI）. Recent studies on PTI regulation and P. syringae effector targets have uncovered new components in PTI signaling. Although MAP kinase （MAPK） cascades have been considered crucial for PTI, emerging evidence indicates that a MAPK-independent pathway also plays an important role in PTI signaling.

关键词： Disease resistance plant-microbe interactions signal transduction PAMP innate immunity receptor.

Nanofabrication of the gold scanning probe for the STM-SECM coupling system with nanoscale spatial resolution

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Science China Chemistry 2017年第5期60卷 649-655页

作者： Fang-Fang Wang Wei Wang Xi He Lianhuan Han jian-zhang zhou Zhong-Qun Tian Zhao-Wu Tian Dongping Zhan State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen University Chemical Engineering and Environmental Engineering College of Chemistry Liaoning Shihua University

Scanning probe is the key issue for the electrochemical scanning probe techniques(EC-SPM) such as EC-scanning tunnel microscopy(STM), EC-atomic force microscopy(AFM) and scanning electrochemical microscopy(SECM), especially the insulative encapsulation of the nanoelectrode probe for both positioning and electrochemical feedbacks. To solve this problem,we develop a novel fabrication method of the gold nanoelectrodes: firstly, a micropipette with nanomter-sized orifice was prepared as the template by a laser puller; secondly, the inside wall of micropipette apex was blocked by compact and conic Au nano-piece through electroless plating; thirdly, the Au nano-piece was grown by bipolar electroplating and connected with a silver wire as a current collector. The fabricated Au nanoelectrode has very good voltammetric responses for the electrodic processes of both mass transfer and adsorption. The advantage lies in that it is well encapsulated by a thin glass sealing layer with a RG value lowered to 1.3, which makes it qualified in the SECM-STM coupling mode. On one hand, it can serve as STM tip for positioning which ensures the high spatial resolution; on the other hand, it is a high-quality nanoelectrode to explore the local chemical activity of the substrate. The nanofabrication method may promote the SPM techniques to obtain simultaneously the physical and chemical images with nanoscale spatial resolution, which opens a new approach to tip chemistry in electrochemical nanocatalysis and tip-enhanced spectroscopy.

关键词： scanning probe SECM bipolar nanoelectrode electrochemical imaging