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Review on ω Phase in Body-Centered Cubic Metals and Alloys

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Acta Metallurgica Sinica(English Letters) 2014年第1期27卷 1-11页

作者： Dehai Ping National Institute for Materials Science Sengen 1-2-1Tsukuba 305-0047Japan

An ω phase with a primitive hexagonal crystal structure has been found to be a ωmmon metastable phase in body-centered cubic （bcc） metals and alloys. In general, ω phase precipitates out as a high density of nanoscale particles and can obviously strengthen the alloys; however, ωarsening of the ω particles significantly reduces the alloy ductility. The ω phase has ωherent interfacial structure with its bcc matrix phase, and its lattice parameters are aω ---- x/2 x abcc and ωbcc= v/3/2 abcc abet. The ωmmon { 112} （111）-type twinning in bcc metals and alloys can be treated as the product of the ω ~ bcc phase transition, also known as the ω-lattice mechanism. The ω phase＇s behavior in metastable 13-type Ti alloys will be briefly reviewed first since the ω phase was first found in the alloy system, and then the existence of the ω phase in carbon steels will be discussed. Carbon plays a crucial role in promoting the ω formation in steel, and the ω phase can form a solid solution with various carbon ωntents. Hence, the martensitic substructure can be treated as an ct-Fe matrix embedded with a high density of nanoscale ω-Fe particles enriched with carbon. The reωgnition of the ω phase in steel is expected to advance the understanding of the relationship between the microstructure and mechanical properties in bcc steels, as well as the behavior of martensitic transformations, twinning formation, and martensitic substructure.

关键词： ω phase Martensitic steel Microstructure Microanalysis bcc metals Alloys Twinning

Accomplishment and challenge of materials database toward big data

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Chinese Physics B 2018年第11期27卷 130-135页

作者： Yibin Xu National Institute for Materials Science 1-2-1 Sengen Tsukuba Ibaraki 3050047 Japa

The history and current status of materials data activities from handbook to database are reviewed, with introduction to some important products. Through an example of prediction of interfacial thermal resistance based on data and data science methods, we show the advantages and potential of material informatics to study material issues which are too complicated or time consuming for conventional theoretical and experimental methods. Materials big data is the fundamental of material informatics. The challenges and strategy to construct materials big data are discussed, and some solutions are proposed as the results of our experiences to construct National Institute for Materials Science（NIMS） materials databases.

关键词： material database big data material informatics machine learning interfacial thermal resistance material identification

High-temperature deformation of L1_2-FCC two-phase Ir-15Nb-Ni refractory superalloys

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中国有色金属学会会刊：英文版 2002年第4期12卷 780-784页

作者： Y.F.Gu, Y.Yamabee Mitarai, S.Nakazawa, H.Harada (National Institute for Materials Science, 1 2 1 sengen, Tsukuba, Ibaraki 305 0041, Japan) National Institute for Materials Science 1-2-1 Sengen Tsukuba 日本 Ibaraki 1-2-1 National Institute for Materials Science 1-2-1 Sengen Tsukuba 日本 Ibaraki 605-A National Institute for Materials Science 1-2-1 Sengen Tsukuba 日本 Ibaraki 305-0041

The creep behaviors of the Ni added Ir 85 Nb 15 alloys were investigated at 1?650～1?800?℃ by compression tests in vacuum. X ray diffractometry, transmission electron microscopy and scanning electron microscopy were conducted to characterize the microstructure and lattice misfit change by the addition of Ni in the Ir 85 Nb 15 alloy. The results reveal that the Ni addition has a significant effect on the creep resistance of the Ir 85 Nb 15 two phase refractory superalloys. Basing on the results, the relationship among the Ni addition, lattice misfit, microstructure development, and the creep behavior in the Ni added Ir 85 Nb 15 alloys is discussed.

关键词：铱合金高温变形高温合金 Ir-15Nb-Ni难熔合金

RESEARCH ON REFRACTORY SUPERALLOYS IN THE HTM 21 PROJECT

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Acta Metallurgica Sinica(English Letters) 2005年第1期18卷 74-80页

作者： Y. Yamabe-Mitarai H. Harada High-Temperature Materials Group National Institute for Materials Science Sengen 1-2-1 Tsukuba Ibaraki 305-0047 JapanHigh-Temperature Materials Group National Institute for Materials Science Sengen 1-2-1 Tsukuba Ibaraki 305-0047 Japan

It was proposed that a new class of alloys based on platinum group metals (PGMs) were called refractory superalloys. These refractory superalloys have an fcc and L12 coherent two-phase structure (similar to that of Ni-based superalloys), high melting temperatures and good potential as structural materials used at temperatures up to 1800 ℃. Our recent results on the microstruc-ture evolution, deformation and fracture behavior of some of these refracotry superalloys, especial Ir- and Rh-base refractory superalloys were reported.

关键词： platinum group metals refractory superalloy microstructure deformation behavior

Thermal Diffusivity Measurements of Li2B4O7 and KNbO3 Solution by Laser Flash Method

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Chinese Physics Letters 2002年第4期19卷 569-571页

作者：金蔚青长岛敏夫等 ShanghaiInstituteofCeramics ChineseAcademyofSciencesShanghai200050 SpaceUtilizationResearchCenter OfficeofSpaceUtilizationSystemNASDA2-1-1SengenTsukubaIbaraki305Japan

The thermal diffusivities of Li2B4O7+KNbO3(20 wt%) solution have been determined at temperatures between 900°C and 990°C using a three-layered laser flash method on the differential scheme. The thermal diffusivity of this Li2B4O7 and KNbO3 solution ranges from 3.6.×10^-3cm^2/s to 4.1×10^-3cm^2/s. A positive temperature dependence of thermal diffusivity of solution is obtained

关键词： Thermal diffusivity

Magnetic Pair-Breaking in Y1-xHoxNi2B2C （x = 0, 0.25, 0.5, 0.75） Single Crystals

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Chinese Physics Letters 2006年第4期23卷 975-977页

作者：赵松睿沈静琴许祝安 Takeya H Hirata K Department of Physics Zhejiang University Hangzhou 310027 National Institute for Materials Science 1-2-1 Sengen Tsukuba Ibaraki 305-0047 Japan

Temperature-dependent resistivity and magnetic susceptibility were studied for quaternary borocarbide intermetallic compounds Y1-xHoxNi2B2C （x = 0, 0.25, 0.5, 0. 75）, which show coexistence of superconductivity with magnetism. In a normal state, the compounds exhibit conventional metallic behaviour. The Debye temperature θD is derived by fitting the temperature dependence of resistivity to the Bloch-Gruneisen expression, i.e. θD scales with M^-0.5 （M is the averaged atomic mass on the Y^3＋ site）, which means that the acoustic mode of the lattice vibrating spectrum is influenced by the Y^3＋ site atoms. Fitting the temperature-dependent magnetic susceptibility above TN to the Curie-Weiss law, effective magnetic moment μeff is deduced, and then de Gennes factor dG is calculated. It is found that as Ho content increases, μeff as well as dG increases and Tc decreases. Moreover, the decrease of Tc scales with dG, i.e., △Te ∝ -nI^2 N （EF ）dG, which is consistent with the prediction of the Abrikosov-Gor＇kov theory. We suggest that pair-breaking effect of magnetic Ho^3＋ ions. The significant impact on To. the depression of Tc could be mainly ascribed to the magnetic change of Debye temperature with Ho content may not have significant impact on Tc.

关键词： ANTIFERROMAGNETIC SUPERCONDUCTOR HONI2B2C ORDER TRANSPORT METALS

Experimental study on the free surface deformation in the oxide melt

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Science China(Technological Sciences) 2005年第5期48卷 481-488页

作者： YODA Shinichi Space Utilization Research Center Office of Space Utilization System JAXA 2-2-1 Sengen Tsukuba Ibaraki 305 Japan

Experiments on the thermocapillary convection of high temperature Bi12SiO20 melts have been carried out in the in situ observation system. The steady flow pattern comprises of the main trunk and branches, which is deemed as the surface deformation. The oscillatory thermocapillary convection is characterized by the oscillatory main trunk and traveling branches. The transition of the melt from steady spatial to oscillatory behavior under the temperature differences 120, 60 and 10 K has been considered. The free surface deformation is observed to transform with the change of the applied temperature difference, which manifests that the thermocapillary convection is sensitive to the temperature difference. Moreover, taking the temperature distribution into account, it is noted that the deformation is formed in the colder area of the melt. The oscillatory frequency of the main trunk, which is also sensitive to the applied temperature difference, increases with the rise of temperature.

关键词： deformation of free surface, in situ observation, thermocapillary convection.

Aerodynamic Study on Supersonic Flows in High-Velocity Oxy-Fuel Thermal Spray Process

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Journal of Thermal Science 2005年第2期14卷 126-129页

作者： Hiroshi KATANODA Takeshi MATSUOKA Seiji KURODA Jin KAWAKITA Hirotaka FUKANUMA Kazuyasu MATSUO The University of Kitakyushu 1-1 Hibikino Wakamatsu-kuKitakyushuFukuoka808-0135 JapanTakagi Precision Dies Co. Ltd.2-4-1 IshidaminamiKokuraminami-kuKitakyushuFukuoka802-0836 JapanNational Institute for Materials Science 1-2-1SengenTsukubaIbaraki305-0047 JapanNational Institute for Materials Science 1-2-1SengenTsukubaIbaraki305-0047 JapanPlasma Giken Co. Ltd.2-1-12BijogiTodaSaitama335-0031 JapanThe University of Kitakyushu 1-1 HibikinoWakamatsu-kuKitakyushuFukuoka808-0135 Japan

To clarify the characteristics of gas flow in high velocity oxy-fuel (HVOF) thermal spray gun, aerodynamic research is performed using a special gun. The gun has rectangular cross-sectional area and sidewalls of optical glass to visualize the internal flow. The gun consists of a supersonic nozzle with the design Mach number of 2.0 followed by a straight passage called barrel. Compressed dry air up to 0.78 MPa is used as a process gas instead of combustion gas which is used in a commercial HVOF gun. The high-speed gas flows with shock waves in the gun and jets are visualized by schlieren technique. Complicated internal and external flow-fields containing various types of shock wave as well as expansion wave are visualized.

关键词：超声流冲击波热喷涂内流热处理

Low-temperature superconductors:Nb_(3)Sn,Nb_(3)Al,and NbTi

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Superconductivity 2023年第2期6卷 35-57页

作者： Nobuya Banno National Institute for Materials Science 1-2-1 SengenTsukuba 305-0047Japan

Low‐temperature superconducting(LTS)wires are of significant importance in high‐field magnet *** developments of the LTS wires are attributed to many ***,Nb_(3)Sn is an attractive superconductor with substantial potential for performance improvement in view of an ideal microstructure that maximizes flux pinning *** date,various reviews have been reported on the physical properties of low‐temperature ***,this review focuses on understanding the fundamental phase formations and microstructural controls of low‐temperature superconductors from the perspectives of growth kinetics,nucleation theory,and chemical potentials to facilitate the syntheses of these superconductors and advancement of wire *** Nb_(3)Sn as an example,the effect of Cu addition to Nb_(3)Sn on Nb/Sn reactive diffusion is briefly ***,representative Nb_(3)Sn formations are schematically summarized to broaden our understanding of the development behaviors of Nb_(3)*** behaviors are qualitatively reviewed in terms of Sn chemical *** mentioning the potential for performance improvement of Nb_(3)Sn,the influences of element additions,specifically those of Zr and Hf additions,resulting in breakthrough microstructural refinements,on Nb/Sn diffusion are ***,strengthening of the matrix via element additions is ***,taking Nb_(3)Al as an example,the features of Nb_(3)Al formation and basic development processes,including low‐temperature processes,metastable phase transformations,and microstructural control,are *** sensitivity,one of the most important properties of Nb_(3)Al,is also briefly ***,taking Nb alloy as an example,α‐Ti precipitation in a binary Nb–Ti system is concisely ***,recently reported new artificial pin incorporation based on a powder method is introduced,followed by a unique study of the application of high‐tem

关键词： Nb_(3)Sn Nb_(3)Al NbTi Growth kinetics Diffusion reaction Microstructure