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NUMERICAL MODELING OF DONGZHUANG RESERVOIR ON JING RIVER

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Journal of Hydrodynamics 2001年第2期13卷 68-71页

作者： Yang, M. Zhang, H.Y. Zhang, J.H. Zhang, H.W. Dept. 5 Beijing Univ. of Aero. and Astron. Beijing 100084 China

The Dongzhuang Reservoir will be constructed on the Jing River, which is laden with the highest sediment concentration in the world. The sediment problem is a key challenge for the reservoir design and management. This paper presents essential data, details of sediment scour and siltation calculated by the numerical modeling based on new fundamental equations. Calculated results prove that the reservoir could preserve long-term storage capacity with the operation was offered by the design department.

关键词： Flow of fluids Mathematical models Sediments Storage (materials)

Development and Oxidation Behavior of Al-Cu-Fe Quasicrystalline Coating on Ti Alloy

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Journal of Materials Science & Technology 2004年第6期20卷 713-715页

作者： Fei CAI, Chungen ZHOU, Huibin XU and Shengkai GONGDepartment of Materials Science and Engineering, beijing univ.rsity of aero.autics and astron.utics, beijing 100083, China Dept. of Mat. Sci. and Eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

An oxidation resistant Al-Cu-Fe quasicrystalline coating was fabricated on substrate of Ti alloy by low pressure plasma spraying (LPPS) method. As-sprayed Al-Cu-Fe coating has a rapidly solidified lamellar microstructure consisting of quasicrystalline phase and crystalline phase. The formation of quasicrystalline coating is related to the annealing. The results from the ox!dat!on experiments showed that Al-Cu-Fe quasicrystalline coating improved the oxidation resistance of Ti-base alloys. During the oxidation period there is no evident spallation of the coating from the substrate. Oxide formed on the surface of Al-Cu-Fe quasicrystalline coating after oxidation consisted of Al2O3. Oxidation occurs Ieading to a change of concentration and phase transformation in the coating surface. Selective oxidation of AI transforms the quasicrystalline phase into the phase.

关键词： Low pressure plasma spray Ti-base alloy Al-Cu-Fe quasicrystal Oxidation Coating

Influence of Water Vapor on the Isothermal Oxidation Behavior of Thermal Barrier Coatings

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Journal of Materials Science & Technology 2004年第1期20卷 38-40页

作者： Chungen ZHOU, Jingsheng YU, Shengkai GONG and Huibin XUDepartment of Materials Science and Engineering, beijing univ.rsity of aero.autics and astron.utics, beijing 100083, China Dept. of Mat. Sci. and Eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

The oxidation of specimens with thermal barrier coating (TBC) consisted of nickel-base superalloy, low-pressure plasma sprayed Ni-28Cr-6AI-0.4Y (wt pct) bond coating and electron beam physical vapor deposited 7.5 wt pct yttria stabilized zirconia (YSZ) top coating was studied at 1050℃ respectively in flows of 02, and mixture of O2 and 5%H2O under atmospheric pressure. The thermal barrier coating has relatively low oxidation rate at 1050℃ in pure O2. Oxidation rate of thermal barrier coating in the atmosphere of O% and 5%H2O is increased The oxidation kinetics obeys almost linear law after long exposure time in the presence of 5% water vapor. Oxide formed along the interface between bond coat and top coat after oxidation at 1050℃ in pure O2 consisted of Al2O3, whereas interfacial scales formed after oxidation at 1050℃ in a mixture of O2 and 5%H2O were mainly composed of Ni(AI,Cr)2O4,NiO and AI2O3. It is suggested that the effect of water vapor on the oxidation of the NiCrAlY coating may be attributed to the increase in Ni and Cr ions transport in the oxides.

关键词： Oxidation Water vapor Thermal barrier coating

Effects of Composition and Thermal Cycle on Transformation Behaviors,Thermal Stability and Mechanical Properties of CuAlAg Alloy

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Journal of Materials Science & Technology 2003年第5期19卷 431-434页

作者： Yunqing MA, Chengbao JIANG, Lifen DENG and Huibin XUDepartment of Materials Science and Engineering, beijing univ.rsity of aero.autics and astron.utics, beijing 100083, China Dept. of Mat. Sci. and Eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

The phase transformation behavior, mechanical properties, and the thermal stability of CuAlAg alloy were studied and minor rare earth (0.1 wt pct La+Ce) was added to improve the mechanical property of the studied alloy. It was found that Ag addition in the CuAl binary alloy can improve the stability of martensitic transformation and high Al content leads to the disappearing of martensitic transformation. The tensile strength and strain of the Cu-10.6AI-5.8Ag (wt pct) alloy were measured to be 383.5 MPa and 0.86%, respectively. With rare earth addition, the tensile strain increased from 0.86% to 1.47%. The CuAlAg alloy did not exhibit martensitic transformation on the second heating process. Its poor thermal stability still needs to be improved.

关键词： High temperature shape memory alloys CuAlAg Transformation behavior Thermal cycle Thermal stability Rare earth Mechanical property

Crystallization Kinetics of NiTi Films with Different Ni Contents

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Journal of Materials Science & Technology 2001年第4期17卷 421-424页

作者： Xunyong JIANG, Huibin XU and Shengkai GONG Department of Materials Science and Engineering, beijing univ.rsity of aero.autics and astron.utics, beijing 100083, China Dept. of Mat. Sci. and Eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

Three kinds of NiTi films with different Ni contents were prepared by DC magnetron sputtering. The crystallization kinetics of amorphous films was determined by using non-isothermal single- scan techniques. The results show that the activation energy of crystallization of Ni-rich NiTi film(Ni 51.10 at. pct, Ti 48.90 at. pct) is 715 kJ/mol; while that of Ti-rich films are similar: one is 445 kJ/mol (Ni 46.74 at. pct. Ti 53.26 at. pct), the other is 418 kJ/mol (Ni 43.21 at. pct, Ti 56.7g at. pct), which i5 lower than Ni-rich film. The Avrami parameter n of different films are 0.92 and 0.74 for Ni-rich film and Ti-rich films, respectively. The difference of kinetic parameters for NiTi films with various Ni contents implies that the crystallization behaviors of these films are distinct, which is confirmed by the calculated isothermal kinetics at different temperatures. The thorough research on this phenomenon is in progress.

关键词： NiTi Crystallization Kinetics of NiTi Films with Different Ni Contents

PREPARATION OF Fe/Ni MULTILAYER FILMS AND THEIR MAGNETIC PROPERTIES

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Acta Metallurgica Sinica(English Letters) 2002年第2期15卷 182-186页

作者： L.L. Liu, X.F. Bi, S.K. Gong, H.B. Xu and X. Y. Yuan Department of Materials Science and Engineering, beijing univ.rsity of aero.autics and astron.utics, beijing 100083, China Dept. of Mat. Sci. and Eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

FeNi multilayer films were prepared by EB-PVD technique. A modified TG-DSC apparatus was used to measure their Curie temperatures, which were around 7600C, lower than that of pure Fe thin films. The easy magnetization axis was in-plane. High temperature annealing in vacuum decreased the coercivity sharply. The saturation magnetization also changed with heat treatment. After annealing at the temperature equal to the substrate temperature during deposition, the saturation magnetization decreased.

关键词： multilayer film EB-PVD. Curie transition point saturation magnetization. coercivity

Laser Shock Processing of an Austenitic Stainless Steel and a Nickel-base Superalloy

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Journal of Materials Science & Technology 2003年第5期19卷 402-404页

作者： Huaming WANG, Xijun SUN and Xiaoxuan LILaboratory of Laser Materials Processing and Surface Engineering, School of Materials Science and Engineering, Beihang univ.rsity (formerly beijing univ.rsity of aero.autics and astron.utics), beijing 100083, China Lab. of Laser Mat. Proc. Sch. of Mat. Sci. and Eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

An austenitic stainless steel 1Cr18Ni9Ti and a solid solution-strengthened Ni-base superalloy GH30 were shock processed using a Q-switched pulsed Nd-glass laser. Microstructure, hardness and residual stress of the laser shock processed surface were investigated as functions of laser processing parameters. Results show that high density of dislocations and fine deformation twins are produced in the laser shock processed surface layers in both the austenitic stainless steel and the nickel-base superalloy. Extensive strain-induced martensite was also observed in the laser shock processed zone of the austenitic steel. The hardness of the laser shock processed surface was significantly enhanced and compressive stress as high as 400 MPa was produced in the laser shock processed surface.

关键词： Laser shock processing Austenitic stainless steel Nickel-base superalloy Surface mechanical properties Residual stress

SUBMERGED IMPINGING JETS WITHIN A FINITE WATER DEPTH

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Journal of Hydrodynamics 2002年第3期14卷 40-43页

作者： Liu, Pei-Qing Hydraulics Lab. of High Speed Flows Sichuan Univ. Chengdu 610065 China Fluid Mech. Inst. Beijing Univ. of Aero. and Astron. Beijing 100083 China

By use of the sheet of laser light and the tracing particle technology, flow visualization tests of complex flow structures for submerged impinging jets within finite water depths are conducted. Typical flow patterns of submerged impinging jets are analysed by the singular topology method. In order to reveal the mechanism of these flows, the diffusive characteristics and turbulent fluctuations of submerged impinging jets are measured by the hot-film anemometer.

关键词： Anemometers Flow of fluids Flow visualization Lasers Turbulence

Responding Depth of Photocatalytic Activity of TiO_2 Self-assembled Films

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Journal of Materials Science & Technology 2004年第4期20卷 472-474页

作者： Weichang HAO, Feng PAN, Tianmin WANG and Shukai ZHENG)Center of Materials Physics and Chemistry, School of Science, beijing univ.rsity of aero.autics and astron.utics, beijing 100083, ChinaDepartment of Materials Science, Lanzhou univ.rsity, Lanzhou 730000, China Ctr. of Mat. Phys. and Chem. Sch. of Sci. Beijing Univ. of Aero. and Astron. Beijing 100083 China Dept. of Mat. Sci. Lanzhou Univ. Lanzhou 730000 China

The electrostatically self-assembly method is getting strategically important to prepare multilayer thin films. With careful choice of component materials, this method should allow for the preparation of multilayer thin films with a variety of excellent technological properties. Ti02/PSS multilayer thin films with ordered structure were prepared by electrostatic self-assembly method. UV-Vis-NIR spectrophotometer, X-ray photoelectron spectroscopy (XPS), and atom force microscopy (AFM) were used to characterize the structure and performance of the multilayer films. Because electrostatically self-assembly method allows molecular-level control over the film composition and thickness, this paper studied the responding depth of photocatalytic activity of Ti02 self-assembled films in detail.

关键词： Responding depth Titanium dioxide Photocatalytic activity Electrostatically self-assembly