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low-angle Grain Boundaries in Sublimation Grown 6H-SiC Crystals

Journal of Rare Earths 2006年第Z1期24卷 8-10页

作者： Jiang Shouzhen Li Xianxiang Dong Jie Chen Xiufang Xu Xiangang Hu Xiaobo State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China

High-resolution X-ray diffractometry(HRXRD)was used to assess the quality of 6H-SiC crystals grown by sublimation *** results show the occurrence of low-angle grain boundaries(LB)is close relative to the inclination of the crystal *** the central faceted region with 0°inclination the crystal is of high structural ***,at the region close to the facet with less than 5°inclination LB occurs slightly and at the region close to the peripheral polytype ring with more than 5°inclination LB defect occurs *** density of LB can be drastically reduced by decreasing radial temperature gradient that determines the shape of the crystal growth interface.

关键词： low-angle grain boundaries sublimation 6H-SiC radial temperature gradient

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Evolution of low-angle Normal Faults in the Enping Sag,the Northern South China Sea: Lateral Growth and Vertical Rotation

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Journal of Earth Science 2019年第6期30卷 1326-1340页

作者： Zhichao Zhou Lianfu Mei Hesheng Shi Yu Shu Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education China University of GeosciencesWuhan 430074China Research Institute of Exploration and Development PetroChina Tuha Oil Field CompanyHami 839000China Shenzhen Branch of the China National Offshore Oil Corporation Shenzhen 518000China

low-angle normal faults(dip<30°,LANFs)are widespread in the northern margin of the South China Sea where the maximum crust thickness is approximately 30.0 *** on 3 D seismic survey data and drilling wells in the Enpi... 详细信息

low-angle normal faults(dipangles are *** a detailed investigation of extensional fault system and description of 3 D fault geometry,the initial fault dips under the model of distributed vertical simple shear are also *** results indicate that the present-day dip angles of the LANFs are in the range of 12°to 29°,and the initial fault dip angles are in the range of 39°to 49°.Deep seismic imaging suggests that the upper crust in the footwall block of the LANFs was tilted at an angle of ~14°to 22°due to the isostatic rebound during ***,the temporal and spatial sequences of the lateral growth of the LANFs have been investigated by the seismic interpretation of four isochronous stratigraphic interfaces,which demonstrates that two individual fault segments propagated towards each other and subsequently,were hard-linked during the Early Eocene.

关键词： low-angle normal fault fault rotation fault growth Enping sag Pearl River Mouth Basin the South China Sea

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Strain and kinematic vorticity analysis of the Louzidian low-angle ductile shear detachment zone in Chifeng,Inner Mongolia,China

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Science China Earth Sciences 2010年第11期53卷 1611-1624页

作者： LI JianBo WANG Tao OUYANG ZhiXia Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China East China Institute of Technology Fuzhou 344000China

The Louzidian low-angle ductile shear detachment zone at the south of Chifeng is a SE-dipping, low-angle normal fault system. It is composed mainly of ductile shear zone, ductile-brittle shear zone and brittle fault zone. The ductile shear zone consists of, from bottom to top, mylonitic rocks, protomylonites and mylonites. Finite strain measurement of feldspar strain markers from those rocks using the Rf /φ method shows that strain intensities (Es) of the mylonite at core of the ductile shear zone (Es=0.65-0.96) are higher than those of the mylonitic rocks close to the granite intrusions (Es=0.59-0.62) and of the protomylonites at top of the ductile shear zone (Es= 0.47-0.70), and the strain types of the protomylonites and mylonties are elongate strain and plane-flattening strain, respectively. The kinematic vorticity values (Wk) estimated by the Polar Mohr diagram and the Rigid Grain Net range from 0.81 to 0.90 with an average of 0.85 for the protomylonites, and from 0.53 to 0.80 with 0.66 on average for the mylonites; Wk values of the extensional crenulation cleavage, i.e., C′, estimated by C′ method range from 0.63 to 0.37 with an average of 0.50. The angles between the maximum principal stress and shearing direction determined using the Maximum effective moment criterion evolved from 61° to 69° and to 75°, and finally normal to shearing direction. The results of strain and kinematic vorticity measurements suggest that high strain corresponds to low kinematic vorticity. Kinematic vorticity measurements show that the Louzidian low-angle ductile shear detachment zone is a result of a combination of simple-dominated general shearing at the early stage and pure-dominated general shearing at the late stage. All these, together with isotope geochronology and regional tectonic background, suggest that the Louzidian ductile shear detachment zone resulted from a combination of crust extension and magma intrusion. The model of simple shear at the early stage and pure shear

关键词： Louzidian low-angle ductile shear detachment zone mylonite strain intensity kinematic vorticity principal stress

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Diffusion behavior of Cr in gradient nanolaminated surface layer on an interstitial-free steel

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Journal of Materials Science & Technology 2019年第3期35卷 460-464页

作者： S.L.Xie Z.B.Wang K.Lu Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

Nanolaminated structures composed of low-angle grain boundaries(LAGBs) possess high thermal stability. In this paper, a gradient nanolaminated(GNL) surface layer with smooth finish was fabricated on an interstitial-free steel by means of surface mechanical rolling treatment. Microstructural observations demonstrated that the average lamellar thickness is about 80 nm in the topmost surface layer and increases with increasing depth. High thermal stability was confirmed in the GNL surface layer after annealing at 500℃. Diffusion measurements showed that effective diffusivity of Cr in GNL layer is 4–6 orders of magnitude higher than lattice diffusivity within the temperature range from 400 to 500℃. This might be attributed to numerous LAGBs or dislocation structures with a higher energy state in the GNL surface layer. This work demonstrates the possibility to advanced chromizing(or other surface alloying)processes of steels with formation of GNL surface layer, so that a thicker alloyed surface layer with a stable nanostructure is achieved.

关键词： Gradient nanolaminated structure Interstitial-free steel Diffusion low-angle grain boundary Surface mechanical rolling treatment

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The Alumina Film Nanomorphology Formed to Improve the Corrosion Resistance of Al-2.0 wt% Fe Alloy as Result of the Laser Surface Melting Technique Applied

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Advances in Chemical Engineering and Science 2017年第1期7卷 10-22页

作者： Moises Meza Pariona Katieli Tives Micene Graduate Program in Engineering and Materials Science State University of Ponta Grossa (UEPG) Ponta Grossa Brazil

The laser surface remelting (LSR) treatment was performed to Al-2.0 wt% Fe alloy with a 2 kW Yb-fiber laser (IPG YLR-2000S). The substrate and laser-treated material characterization were executed using different techniques. Among them, the microstructure was analyzed by optical microscope, SEM, low-angle X-ray diffraction (LAXRD) and the corrosion test was made in aerated solution of 0.1 M H2SO4 at a temperature of 25°C ± 0.5°C. As result was shown, the micrograph of LSR-treated material displaying can be a fine cellular structure and the existence of certain nano-porosities and a similar to a nano-dendritic growth was observed too. The characteristic of melted zone was constituted of metastable phases according to the result of x-rays and the behavior corrosion as a result of the LSR-treated sample, which it was shown to be more resistant to corrosion than the untreated sample. A comparative study was carried out of the cyclic polarization of the laser-treated and untreated samples, demonstrating that the reduction and oxidation reverse peaks were not observed and being the cyclic polarization behavior was of irreversible character in both samples, however, the LSR-treated sample propitious the passivity on the surface also reduced the corrosion phenomena. Wherefore, this type of laser-treated alloy can be applied in the aerospace, aeronautic and automobilist industries.

关键词： Al-2.0 wt% Fe Alloy Laser-Treated Microstructure low-angle X-Ray Diffraction Cyclical Polarization

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