材料期刊网

A CHALLENGE FOR BIAXIAL AND TRIAXIAL CREEP TESTING

M. Sakane (Department of Mechanical Engineering , Faculty of Science and Engineering , Ritsumeikan University , 1-1-1Nojihigashi Kusatsu-shi Shiga , 525-8577 , Japan)S. Mukai (Power Reactor and Nuclear Fuel Development Corporation , 4002 Narita-cho Oarai-cho Ibaragibun Ibaragi , 311-13 , Japan)

金属学报(英文版)

This paper describes new methods for biaxial and triaxial creep testing. Biaxial tension and triaxial tension creep testers were developed. The performance of the machines was described and some test results were discussed. Stress biaxiality had almost no effect on the creep deformation and Mises potential was suitable for describing the creep deformation under biaxial and triaxial stress states. Stress biaxiality had a small influence on prolonging creep rupture time under the constant Mises stress condition.A new triaxial tension creep testing method was discussed together with the shape of the triaxial creep specimen.

关键词: creep , null , null , null , null

Systematic impact of spent nuclear fuel on θ13 sensitivity at reactor neutrino experiment

中国物理C

关键词:

DEVELOPMENT OF THE RISK-BASED MAINTENANCE OPTIMIZATION SYSTEM FOR FOSSIL POWER PLANTS

D.Watanabe

金属学报(英文版)

Cost reduction in electric power generation is a major management concern, and it is therefore necessary to reduce maintenance expenses while upholding plant reliability. A maintenance optimization system "FREEDOM", which uses RBM technique, DCF (discounted cash flow) and NPV (net present value) calculation functions, has been newly developed. This system probabilistically evaluates the lifetime of boiler and turbine and quantitatively calculates the risk defined as the cumulative probability of failure multiplied by the consequence of failure. Economically optimized timing of inspection and alternative countermeasure such as repair and replacement are then recommended. This system has already been applied to seven plants in Japan, and its effectiveness has been confirmed.

关键词: plant asset management , null , null

Modeling flow stress constitutive behavior of SA508-3 steel for nuclear reactor pressure vessels

Journal of Nuclear Materials

Based on the measured stress-strain curves under different temperatures and strain rates, a series of flow stress constitutive equations for SA508-3 steel were firstly established through the classical theories on work hardening and softening. The comparison between the experimental and modeling results has confirmed that the established constitutive equations can correctly describe the mechanical responses and microstructural evolutions of the steel under various hot deformation conditions. We further represented a successful industrial application of this model to simulate a forging process for a large conical shell used in a nuclear steam generator, which evidences its practical and promising perspective of our model with an aim of widely promoting the hot plasticity processing for heavy nuclear components of fission reactors. (c) 2011 Elsevier B.V. All rights reserved.

关键词: low-alloy steels;low-carbon steel;hot deformation;mechanical-properties;fracture-toughness;temperature;austenite;working

Characterisations of electrospark deposition Stellite 6 alloy coating on 316L sealed valve used in nuclear power plant

Materials Science and Technology

In nuclear plant the protection of the H(2)BO(4) solution seal areas of AISI 316L austenitic steel is accomplished by Stellite 6 plasma cladding layer. Wear defects created in service required the part to be replaced or repaired. No existing repair technologies were practical. Electrospark deposition (ESD) was to repair defects, enabling the parts to be placed back in service. In this paper the authors report the results obtained depositing directly a layer of Stellite 6 alloy onto a 316L austenitic stainless and Stellite 6 plasma cladding layer by using ESD technique. Electrospark deposition can apply metallurgical bonded coatings without the need of post-heat treatment. Structure, hardness, chemical composition and morphology of the ESD coating have been analysed. By electrochemical measurements it is inferred that the corrosion resistance of the ESD coating is comparable to that of the 316L and Stellite 6 plasma cladding layer. The hardness improvement was ascribed to the refine microstructure and the rapid solidification.

关键词: Electrospark deposition;AISI316L stainless steel;Plasma cladding;Stellite 6

Practice for Extending Blast Furnace Campaign Life at Wuhan Iron and Steel Corporation

ZHANG Shourong

钢铁研究学报(英文版)

One of the problems encountered in 60′s to 80′s of 20th century in China′s steel industry was short life of blast furnace shaft as well as the excessive erosion of blast furnace hearth. A series of research work was carried out in order to extend blast furnace campaign life. The concept of research and development was integrated in the construction of BF (blast furnace) No5 at WISCO (Wuhan Iron and Steel Corporation), and in October, 1991, the BF No5 was blown in. The blast furnace has worked smoothly for more than 15 years without any medium repair even guniting. It is expected that the campaign life of BF No5 would be longer than 16 years with a production over 11 000 t per unit inner volume (m3). A new blast furnace with an inner volume of 3 400 m3 is under construction, and is designed with a campaign life of 20 years without any medium repair. The campaign life of blast furnaces in China has been extended in recent years.

关键词: blast furnace;campaign life;erosion

Development of yttria-stabilized zirconia thin films via slurry spin coating for intermediate-to-low temperature solid oxide fuel cells

Journal of Power Sources

Yttria-stabilized zirconia (YSZ) thin films were successfully fabricated on porous NiO-YSZ anode substrates via a slurry spin coating method. With similar to 34-mu m-thick Sm0.2Ce0.80O1.9 (SDC)-impregnated La(0.7)Sr(0.3)Mno(3) (LSM) cathodes, a single cell based on a similar to 9-mu m-thick YSZ film exhibited a good performance at intermediate-to-low temperature. The cell produced an open-circuit voltage (OCV) of similar to 1.08 V, and maximum power densities of similar to 0.42 and similar to 0.70 W cm(-2) at 650 degrees C, while the cathode was exposed to the stationary air and blown with 100 mL min(-1) oxygen airflow, respectively. Enhanced cell performance with oxygen airflow was attributed to the improved cathode performance. By separating the total voltage drop into ohmic and non-ohmic contributions, it could be concluded that the cell performance was primarily determined by the polarization of the electrodes. It is believed that by optimizing the film fabrication process and improving the cathode performance, intermediate-to-low temperature solid oxide fuel cells (SOFCs) based on supported YSZ electrolyte thin films could be put into practice in not far future. (c) 2006 Elsevier B.V. All rights reserved.

关键词: solid oxide fuel cells (SOFCs);slurry spin coating;yuria-stabilized;zirconia thin film;impregnation;oxygen airflow;fabrication;electrolyte;membranes;cathodes;sofcs

Development of LSM-based cathodes for solid oxide fuel cells based on YSZ films

Journal of Power Sources

In an attempt to achieve desirable cell performance, the effects of La0.7Sr0.3MnO3 (LSM)-based cathodes on the anode-supported solid oxide fuel cells (SOFCs) were investigated in the present study. Three types of cathodes were fabricated on the anode-supported yttria-stabilized zirconia (YSZ) thin films to constitute several single cells, i.e., pure LSM cathode, LSM/YSZ composite by solid mixing, LSNVSM0.2Ce0.8O1.9 (SDC) composite by the ion-impregnation process. Among the three single cells, the highest cell output performance 1.25 W cm(-2) at 800 degrees C, was achieved by the cell using LSM/SDC cathode when the cathode was exposed to the stationary air. Whereas, the most considerable cell performance of 2.32 W cm(-2) was derived from the cell with LSM/YSZ cathode, using 100 ml min(-1) oxygen flow as the oxidant. At reduced temperatures down to 700 degrees C, the LSM/SDC cathode was the most suitable cathode for zirconia-based electrolyte SOFC in the present study. The variation in the cell performances was attributed to the mutual effects between the gas diffusing rate and three-phase boundary length of the cathode. (c) 2007 Elsevier B.V All rights reserved.

关键词: SOFC;LSM;YSZ film;TPB;porosity;yttria-stabilized zirconia;impedance spectroscopy;composite cathodes;performance;sofcs;electrolyte;temperature;fabrication

R & D OF HYDROGEN ABSORBING ALLOYS IN JAPAN

K. Mii (Sumitomo Metal Industries , Ltd. , 1-t-3 Otemachi , Tokyo 100 , Japan)M Amano (National Research Institute for Metals , 1-2-1 Sengen , Tsukuba 305 , Japan)

金属学报(英文版)

The R & D of hydrogen absorbing alloys in Japan started in the early 1970s.Many alloys such as TiMm1.5 based alloys, Fe-Ti-O alloys (e.g. FeTi1.15 O0.024) andthe(mischmetal)Ni5 based alloys (e.g. MmNi4.5 Cr0.46 Mn0.04) were developed by the early 1980s. The application of these alloys to hydrogen storage, heat storage, heat pump, hydrogen purification and motor vehicles has been tried in many iaboratories,and the various techniques for using hydrogen absorbing alloys have been developed.The standarkization of evaluation methods for hydrogen absorbing alloys has been promoted by the Ministry of International Trade and Industry (MITI), and four of them were established as Japanese Industrial Standard (JIS).Alloys for Ni-Metal Hydride batteries have been extensively investigated since 1987in Japun. Mm-Ni-Co-Al-Mn alloys (e.g. MmNi3.55 Co0.75Al0.9Mn0.4) have been devel-oped and commereialized since 1990. The amount of production of small-size Ni-MH batteries in 1995 was about three hundred milliion in number and about one hundred billion yen. The R & D for higher enerpy-density Ni-MH batteries is intensively in progress.MITI and STA (Science and Technology Agency) have promoted the R & D of hydro-gen absorbing alloys in Japan by carrying out the national projects such as Sunshine Program (MITI: 1974-1993) and Utilization of Wind Engeray (STA 1980-1985). The New Sunshine Program (MITI 1993-2020) have started in 1993. This program con-tains the application of hydrogen absorbing alloys to Economical- Enerpy- City System and to We-NET (International Clean Energy System of Technology Utilizing Hydro-gen: World Energy Network.

关键词: hydrogen absorbing alloy , null , null , null

Photoluminescence study of Ge nanocrystals irradiated by reactor neutron flux

Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms

Samples of Ge nanocrystals (Ge-ncs) embedded in amorphous SiO2 film were prepared by Ge ion implantation and subsequent primary thermal annealing. These samples were irradiated by neutron flux in a nuclear reactor followed by the second annealing. Irradiation with thermal neutrons leads to doping of nanocrystals with Ga, As and Se impurities due to nuclear transmutation of isotope Ge-70 into Ga-71, isotope 74 Ge into 75 As, isotope 76 Ge into 77 Se, respectively (neutron transmutation doping, NTD). Irradiation with fast neutrons leads to appearance of radiation damages, which are expected to be removed after the second annealing. Photoluminescence (PL) measurements show that PL is quenched after neutron irradiation, and restored after annealing higher than 500 degrees C. The PL spectra of doped Ge-nes samples show more intense exciton radiative luminescence than of undoped Ge-ncs sample, which is related to that the donor and acceptor impurities recombine the nonradiative centers in the interface of Ge-ncs and SiO2 matrix, and enhance the probability of exciton recombination. (c) 2007 Elsevier B.V. All rights reserved.

关键词: Ge nanocrystals;neutron transmutation doping;photoluminescence;Raman;scattering;doped si nanocrystals;electron-spin-resonance;semiconductor;nanocrystals;n-type;implanted sio2-films;silicon nanocrystals;porous;silicon;raman;luminescence;temperature