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Static recrystallization behavior of hot-deformed magnesium alloy AZ31 during isothermal annealing

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transactions of Nonferrous Metals Society of China 2010年第7期20卷 1269-1274页

作者：杨续跃朱亚坤 H.MIURA t.sakai School of Materials Science and Engineering Central South University Department of Mechanical Engineering and Intelligent Systems University of Electro Communications

the static recrystallization of hot-deformed magnesium alloy AZ31 during isothermal annealing was studied at temperature of 503 K by optical and SEM/EBSD metallographic *** grain size change during isothermal annealing is categorized into three regions,*** incubation period for grain growth,rapid grain coarsening,and normal grain *** number of fine grains per unit area,however,decreases remarkably even in incubation *** leads to grain coarsening taking place continuously in the whole period of *** contrast,the deformation texture scarcely changes even after full annealing at high *** is concluded that the annealing processes operating in hot-deformed magnesium alloy with continuous dynamic recrystallized grain structures can be mainly controlled by grain coarsening without texture change,that is,continuous static recrystallization.

关键词： magnesium alloy AZ31 annealing continuous recrystallization grain growth texture

Dynamic recrystallization and texture development during hot deformation of magnesium alloy AZ31

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中国有色金属学会会刊：英文版 2009年第1期19卷 55-60页

作者：杨续跃吉泽升 H. MIURA t. sakai School of Materials Science and Engineering Central South University Key Laboratory of Nonferrous Metal Materials Science and Engineering Ministry of Education Central South University College of Materials Science and Engineering Harbin University of Science and Technology Department of Mechanical Engineering and Intelligent Systems UEC Tokyo Tokyo 182-8585 Japan

the dynamic recrystallization(DRX) and texture development, taking place during hot deformation of magnesium alloy AZ31 with a strong wire texture, were studied in compression at 673 K (0.73 tm). two kinds of samples were machined parallelly to the extruded and transverse directions of Mg alloy rods. New fine grains are evolved at original grain boundaries corrugated at low strains and develop rapidly in the medium range of strain, finally leading to a roughly full evolution of equiaxial fine grains. Kink bands are evolved at grain boundaries corrugated and also frequently in grain interiors at low strains. the boundary misorientations of kink band increase rapidly with increasing strain and approach a saturation value in high strain. the average size of the regions fragmented by kink band is almost the same as that of new grains evolved in high strain. these characteristics of new grain evolution process are not changed by the orientation of the samples, while the flow behaviors clearly depend on it. It is concluded that new grain evolution can be controlled by a deformation-induced continuous reaction, i.e. continuous dynamic recrystallization(DRX). the latter is discussed by comparing with conventional, i.e. discontinuous DRX.

关键词：镁合金 AZ31合金连续动态热处理

Application of tungsten as a De-NO_x Catalyst

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Rare Metals 1994年第3期13卷 229-235页

作者： Nakatsuji t.(sakai Chemical Industry, Co. , LId. 5-I, Ebisujimacho sakai Osako 590, Japan) sakai Chemical Industry Co 日本

Abstract A catalyst for removal of nitrogen oxides, in stationary Sources, requires many kinds of characteristicsfor commercial application. At first, a vanadium pentaoxide based catalyst was used for the NO-NH3-OZreaction because of its high activity at lower temperatures. But it was`later found that this catalyst had *** like a low thermal durability and a high conversion rate of SO: to SO3. On the other hand, tungstentrioxide was well known as a catalyst that has a high thermal durability and a low conversion rate of SOZto SO3 but showed a low activity at appropriate temperature. For these reasons, tungsten trioxide basedcatalysts have not been used in the reaction in most actual plants except for special cases. Further *** on this catalyst revealed that a catalyst comprising of titania f80 wt%￣ 90 wt%j- tungsten trioxide(5 wt% ￣ 15 wt%j, and vanadium pentaoxide (0,l wt%￣ 5 wt%j, showed a high thermal durability and alow conversion rate of SOZ to SO3 as well as high activity towards the NO-NHrOz reaction.

关键词： NO De

Microstructure and mechanical properties of AZ61 Mg alloy prepared by multi directional forging

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transactions of Nonferrous Metals Society of China 2010年第7期20卷 1294-1298页

作者： H. MIURA G. YU X. YANG t. sakai Department of Mechanical Engineering and Intelligent Systems University of Electro-Communications Chofu Tokyo 182-8585 Japan School of Materials Science and Engineering Central South University Changsha 410083 China

AZ61Mg alloy was multi directionally forged(MDFed) during decreasing temperature condition from 643 K to 483 K at a true strain rate of 3×10-3 s-1 up to cumulative strain of∑△ε=4.0 at maximum.A pass strain of△ε=0.8 was *** average grain size decreased gradually with increasing cumulative strain,the evolution of fine-grained structure strongly depended on the MDF *** the condition where the temperature was higher than the most adequate one,grain coarsening partially took place during *** contrast,at lower temperature,inhomogeneous microstructure composed of the initial coarse and newly appeared fine grains was *** straining over∑△ε=3.2(i.e.,over 4 passes of MDF) ,equiaxed ultrafine grains(UFGs) having average size of about and lower than 1μm were uniformly *** the MDFed alloy to∑△ε=4.0 possessed relatively high hardness of HV 99,and it accepted further about 20%cold rolling almost without *** of the superior formability of the UFGed AZ61Mg alloy,the hardness was further easily raised to HV 120 by following cold rolling.

关键词： AZ61 magnesium alloy ultrafine grain plastic deformation multi directional forging

Databook on Fatigue Strength of Metallic Materials

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Journal of Materials Science & technology 1998年第2期14卷 191-192页

作者： K.Shiozawa toyama t.sakai Shiga

Using LiF crystals for high-performance neutron imaging with micron-scale resolution

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High Power Laser Science and Engineering 2015年第4期3卷 1-9页

作者： A.Faenov M.Matsubayashi t.Pikuz Y.Fukuda M.Kando R.Yasuda H.Iikura t.Nojima t.sakai M.Shiozawa R.Kodama Y.Kato Institute for Academic Initiatives Suita Osaka University Joint Institute for High temperatures Russian Academy of Sciences Quantum Beam Science Center Japan Atomic Energy Agency PPC and Graduate School of Engineering Suita Osaka University Nippon SOKEN Inc. the Graduate School for the Creation of New Photonics Industries

this paper describes an overview of our recent discovery – clear demonstration that Li F crystals can be efficiently used as a high-performance neutron imaging detector based on optically stimulated luminescence of color centers generated by neutron irradiation. It is shown that the neutron images we have obtained are almost free from granular noise, have a spatial resolution of～5.4 μm and a linear response with a dynamic range of at least 103. the high contrast and good sensitivity of Li F crystals allow us to distinguish two holes with less than 2% transmittance difference. We propose to use such detectors in areas where high spatial resolution with high image gradation resolution is needed, including diagnostics of different plasma sources such as laser and z-pinch produced plasmas.

关键词： color centers Li F crystals neutron imaging neutrons plasma diagnostics

Development of an Automatic Gain Controller Card for Next Generation EDFAs

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光学学报 2003年第S1期23卷 413-414页

作者： C. Y. Liaw t. H. Cheng C. Lu M.Akiyama t.sakai A.Wada Institute for Infocomm Research Unit 230 Innovation Centre Block 2 18 Nanyang Drive Singapore 639798 Fujikura technology Singapore 41 Science Park Road #01-03 Singapore 117610 Fujikura Ltd 1440 Mutsuzaki Sakura Chiba 285-8550 Japan

this paper describes a low cost automatic gain controller card that provides fast transient gain control to maintain the power of the surviving channels when the number of input channels to an erbium-doped fiber ampli... 详细信息

关键词： fiber amplifier gain control low cost

ULtRAFINE GRAIN FORMAtION IN FCC MEtALS DURING SEVERE PLAStIC DEFORMAtION

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ULTRAFINE GRAIN FORMATION IN FCC METALS DURING SEVERE PLASTI...

temperature Effect on Deformation Microstructures in Austenite

第五届国际材料与热加工物理模拟及数值模拟学术会议

作者： t. sakai H. Miura Department of Mechanical Engineering and Intelligent Systems UEC tokyo (the University of Electro-Communications) Chofu Tokyo 182-8585 Japan

the evolution mechanisms of new high-angle boundaries as well as ultrafine grains in large strain were studied by means of multidirectional forging (MDF) for pure copper at low temperature and aluminum alloy at high temperature, where dynamic recovery operates as a restoration process. MDF were carried out using rectangular samples with consequent changing of the loading direction in 90o through three of mutually perpendicular axes. the structural changes can be characterized by the evolution of deformation bands such as microshear or kink bands at moderate strains. MDF accelerates the evolution of many mutually crossing microshear or kink bands developed in various directions. the (sub)grains become more equiaxed and the misorientations between them gradually increase with increase in cumulative strain, finally leading to the development of a new fine-grained structure. It is concluded that the dynamic grain formation can result from a kind of continuous reactions involving grain fragmentation due to deformation bands, i.e. in-situ or continuous dynamic recrystallization.

关键词： Ultrafine grained structure severe plastic deformation multidirectional forging grain fragmentation microshear band dynamic recovery continuous dynamic recrystallization.

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Temperature Effect on Deformation Microstructures in Austeni...