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Microstructure Characteristics of an Fe-Mn-C TWIP Steel After Deformation

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Journal of Iron and Steel Research International 2010年第9期17卷 53-59页

作者： DAI Yong-juan tang di MI Zhen-li LU Jian-chong National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing Beijing 100083 China School of Materials Science and Engineering Hebei University of Science and Technology Shijiazhuang 050018 Hebei China

The microstructure characteristics of an Fe-Mn-C TWIP steel after deformation are investigated. The results show that the hot-rolled, cold-rolled and then annealed sample of the Fe-Mn-C TWIP steel has excellent mechanical properties, and the true stress-true strain curve from tension tests exhibits repeated serrations. The deformed microstructure exhibits the typical planar glide characteristics such as no cell formation, dislocation pile-ups on a single slip plane, mechanical twins and stacking faults. There are equiaxial and deep dimple structures in the fractograph, indicative of a ductile fracture. Microcracks initiate from inclusions and twin-twin intersections. Deformation and fracture processes are the formation, growth and coalescence of microvoids.

关键词： planar glide deformed twinning stack fault energy ductile fracture

The comparison of H_2CO(1_(10)–1_(11)),C^(18)O(1–0) and the continuum towards molecular clouds

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Research in Astronomy and Astrophysics 2014年第8期14卷 959-970页

作者： Xin-di tang Jarken Esimbek Jian-Jun Zhou Gang Wu Daniel Okoh Xinjiang Astronomical Observatory Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Radio Astronomy Chinese Academy of Sciences Physics & Astronomy Department University of Nigeria

We present large scale observations of C^18O （1-0） towards four massive star forming regions： MON R2, S156, DR17/L906 and M17/M18. The transitions of H2CO （110-111）, C^18O （1-0） and the 6cm continuum are compared in these four regions. Our analysis of the observations and the results of the Non-LTE model shows that the brightness temperature of the formaldehyde absorption line is strongest in a background continuum temperature range of about 3 - 8 K. The excitation of the H2CO absorption line is affected by strong background continuum emission. From a comparison of H2CO and C^18O maps, we found that the extent of H2CO absorption is broader than that of C^18O emission in the four regions. Except for the DR17 region, the maximum in H2CO absorption is located at the same position as the C^18O peak. A good correlation between intensities and widths of H2CO absorption and C^18O emission lines indicates that the H2CO absorption line can trace the dense, warm regions of a molecular cloud. We find that N（H2CO） is well correlated with N（ C^18O） in the four regions and that the average ratio of column densities is （N（H2CO）/N（ClSO））～0.03.

关键词： ISM clouds -- molecules -- stars formation

Measuring the flexibility matrix of an eagle’s flight feather and a method to estimate the stiffness distribution

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Chinese Physics B 2019年第7期28卷 305-311页

作者： di tang Hai Zhu Wei Yuan Zhongyong Fan Mingxia Lei College of Mechanical Engineering Zhejiang University of Technology Hangzhou 310014 China High Speed Aerodynamic Institute China Aerodynamics Research and Development Center Mianyang 621000 China Zhejiang Museum of Natural History Hangzhou 310014 China

Flight feathers stand out with extraordinary mechanical properties for flight because they are lightweight but stiff *** elasticity has great effects on the aerodynamics, resulting in *** primary task is to figure out the stiffness distribution of the feather to study the aeroelastic *** feather shaft is simplified as a beam, and the flexibility matrix of an eagle flight feather is tested.A numerical method is proposed to estimate the stiffness distributions along the shaft length based on an optimal Broyden–Fletcher–Goldfarb–Shanno(BFGS) method with global *** analysis of the compressive behavior of the shaft based on the beam model shows a good fit with experimental *** stiffness distribution of the shaft is finally presented using a 5 th order polynomial.

关键词： feather stiffness distribution flexibility matrix optimal Broyden–Fletcher–Goldfarb–Shanno(BFGS)

Scientific literature addressing brain glioma in the Web of Science A 10-year bibliometric analysis

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Neural Regeneration Research 2011年第32期6卷 2537-2544页

作者： Zaihua Xu Tao tang Dongsheng Pan di Fan Zhenquan Song Hongli Xue Department of Neurosurgery General Hospital of Shenyang Military Command of Chinese PLA Shenyang 110016 Liaoning ProvinceChina

Brain glioma is a hot topic in recent years; however, brain glioma remains poorly understood. A bibliometric analysis based on the Science Citation Index （SCI） published by the Institute of Scientific Information （ISI） was performed to identify the global research and to improve the understanding of research trends in the brain glioma field from 2001 to 2010. During 2001 to 2010, there were 8 413 papers addressing brain glioma added to the SCI, and this trend is increasing annually. Of these reports, 6 945 papers are written in English. Journals published in the United States had the most papers, including ten core source titles. The Journal of Neuro-Oncology published the most articles followed by Cancer Research. Furthermore, the University of California San Francisco, is the most productive institution for publishing articles in the brain glioma field. Finally, this study highlights the topics in brain glioma research that are being published around th~ world.

关键词： brain glioma bibliometrics SCI analysis scientific literature

Influence of Chromium on Corrosion Behavior of Low-alloy Steel in Cargo Oil Tank O_2-CO_2-SO_2-H_2S Wet Gas Environment

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Journal of Iron and Steel Research International 2015年第7期22卷 630-637页

作者： Peng ZHOU Jin-ming LIANG Fei ZHANG Hui-bin WU di tang National Engineering Research Center of Advanced Rolling Technology University of Science and Technology Beijing

As international maritime organization （IMO） draft 289 was adopted to develop a low-alloy anti-corrosion steel for the deck of cargo oil tank and to understand corrosion mechanism, corrosion behavior of a low-alloy steel with chromium contents was studied in O2-CO2-SO2-H2 S wet gas environment. Corrosion rate was measured, and the microstructure and morphology of corrosion product film were characterized by scanning electron microscopy （SEM）. The phase and chemical composition of the corrosion product film were investigated by X-ray diffraction （XRD） and energy dispersive spectroscopy （EDS）, respectively. The effect of misorientation distribution on corro- sion resistance of steel was evaluated by electron backscattered diffraction （EBSD）. The results showed that corro- sion rate decreased with increasing chromium content in the low-alloy steel, and the corrosion type was general corrosion. The phenomenon of chromium enrichment was found in corrosion product film consisting of a-FeOOH, γ- FeOOH, sulphur, FeS2 and Fel-xS. The increase of chromium content decreases the amount of high-angle grain boundaries, thus resulting in the improvement of corrosion resistance.

关键词： corrosion cargo oil tank upper deck wet gas low-alloy steel chromium

Characterizing the Structure Evolution of Tertiary Scale during Simulated Coiling by EBSD

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Journal of Iron and Steel Research International 2014年第2期21卷 215-221页

作者： Sheng LIU Hui-bin WU Xiao LI Hai-tao JIANG di tang National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing

An oxide scale formed at 900 ℃ for 60 s in dry air was subjected to the simulated coiling processed with different coiling temperatures. The phase transformation behavior, especially the orientation distribution of the oxide scale, was analyzed using electron backseattered diffraction （EBSD） technique. When cooling from the coiling tem- perature of 650 ℃, the scale consists of FeaO4 layer, FeO layer and FeaO4 seam. The FeaO4 precipitates are ob served in the FeO grains of the scale formed with the coiling temperature of 550 and 450 ℃. With the cofling temperature of 350 ℃, the decomposition of FeO is suppressed due to the low temperature. The Fe3O4 grains, which are decomposed from FeO, has the same orientation as the parent FeO grains. Moreover, the FeO grains, of which the growth direction is parallel to 〈001〉, is easier to decompose into Fe3O4 than the grains with other orientations.

关键词： electron backscattered diffractiom oxide scale mierostructure texture

Application of Computer Algebra in Solving Chaffee-Infante Equation

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Communications in Theoretical Physics 2008年第4期49卷 825-828页

作者： XIE Fu-ding LIU Xiao-Dan SUN Xiao-Peng tang di Department of Computer Science Liaoning Normal University Dalian 116029 China Key Laboratory of Mathematics Mechanization AMSS the Chinese Aca~lemy of Sciences Beijing 100080 China

In this paper, a series of two line-soliton solutions and double periodic solutions of Chaffee-Infante equation have been obtained by using a new transformation. Unlike the existing methods which are used to find multiple soliton solutions of nonlinear partial differential equations, this approach is constructive and pure algebraic. The results found here are tested on computer and therefore their validity is ensured.

关键词： Chaffee-Infante equation two line-soliton solution double periodic solution

Complex Precipitation Mechanism of Ti-Nb-V Microalloyed Bainitic Base High Strength Steel

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Journal of Wuhan University of Technology(Materials Science) 2019年第6期34卷 1444-1450页

作者： PANG Qihang GUO Jing LI Weijuan tang di ZHAO Zhengzhi QI Huan WANG Jiaji School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051China State Key Laboratory of Metal Material for Marine Equipment and Application Anshan 114009China Engineering Research Institute University of Science and Technology BeijingBeijing 100083China

The addition of high Ti（>0.1%） in microalloyed bainitic high strength steel was designed, and the precipitation morphology of steels with different Ti, Nb, and V contents was studied by utilizing transmission electron microscopy（TEM）. Based on the classical nucleation-crystal growth theory and the Johnson-Mehl-Avrami equation, the precipitation thermodynamic and kinetic model of second phase particles in austenite was established in the form of（Nbx,Vy,Tiz）C, and the complex precipitation mechanism of second phase particles was emphatically studied. The experimental results show that the complex precipitation particles could be divided into two categories: the coarser particles with about 100 nm grain size and the independent complex precipitation particles in the form of（Nb,V,Ti）C with 35-50 nm grain size. The latter has a better precipitation strengthening effect, and the calculated PTT curve shows a typical "C" shape. When the deformed storage energy is 3 820 J?mol-1, the fastest precipitation temperature of calculated PTT curve is 925 °C, and the calculated result is essentially consistent with experimental values. The increase of Ti content increased the nose point temperature and expanded the range of fastest precipitation temperature.

关键词： bainite base high strength steel therm odynamic and dynamic complex precipitation behavior precipitation morphology

Deformation behavior and microstructural evolution in ultra-highstrength dual-phase(UHS-DP1000)steel with different strain rates

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Journal of Iron and Steel Research International 2019年第2期26卷 173-181页

作者： Mei Xu Hui Li Rui-ting Jiang di tang Hai-tao Jiang Zhen-li Mi Institute of Engineering Technology University of Scienee and Technology BeijingBeijing 100083China College of Engineering Yantai Nanshan UniversityYantai 265700ShandongChina Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China

The dynamic tensile behavior and deformation mechanism of ultra-high-strength dual-phase(UHS-DP1000)steel were investigated over a wide range of strain rates from 10^-4 to 10^3 s^-*** the strain rate increases,the transition strain decreases from 2.73 to 1.92,and the martensite plastic deformation starts *** strain rate of 10^-4-0.5 s^-l,the inhomogeneous plastic deformation ability increases because the dislocation density in the ferrite matrix *** leads to a decrease in uni form elongation and an increase in fracture *** the strain rate increases from 0.5 to 500s^-*** amount of mobile dislocation increases,which is the main reason for the enhancing uniform elongation and fracture *** nwhile,because the dislocation motio n resistance rapidly in creases,the yield strength and ultimate tensile strength also *** the strain rate is higher than 500 s^-*** hardening behavior caused by the dislocation motion resistance has not been offset by softening due to the mobile dislocation and adiabatic *** voids at the early stage of deformation could not uniformly form and grow,and thus the homogeneous plastic deformation ability decreases.

关键词： Ultra-high-strength dual-phase steel Strain rate Microstructural evolution Void Adiabatic heating