著者

中村 崇 植田 安昭 Toguri James M.

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.50, no.5, pp.456-461, 1986 (Released:2008-04-04)

参考文献数

33

被引用文献数

5 35

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A new scale of the theoretical optical basicity was established by means of the concept of the average electron density (D) expressecl in eq. (1).(This article is not displayable. Please see full text pdf.) \ oindentThe value of α in an oxide system was defined unity, and the values of α in alkaline earth fluoride and chloride systems were determined by measurments of Pbs-p spectra of CaF2 and CaCl2 using photoacoustic spectroscopy.The basicity moderating parameter values were found to have a linear relation with the values of the average electron density, as shown in eq. (2).(This article is not displayable. Please see full text pdf.) The theroretical optical basicity values of transition metal oxides were able to be calculated in the new scale, for example, ΛFeO=0.94, ΛFe2O3=0.72 and ΛTiO2=0.65. It was possible to explain the sulfide capacity values in the systems containing iron oxides using these optical basicity values. The theoretical optical basicity values of alkaline earth fluoride and chloride were also obtained in this study. The values of the optical basicity showed a good correlation to logarithmic values of the phosphate capacity at a constant temperature in the systems consisting of oxide and fluoride compounds. It is suggested that the theoretical optical basicity developed in this study was a resonable scale for a wide range basicity in slags and fluxes.

著者

渋江 和久 熊谷 正樹 金 睦淳

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.56, no.12, pp.1457-1462, 1992 (Released:2008-04-04)

参考文献数

10

被引用文献数

3 10

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The oxidation property of a Ti-33.5 mass%Al-2.5 mass%Mn intermetallic compound prepared by a reactive-sintering process was studied at 1223 K in air in comparison with that by a melt process. The reactive-sintered alloy had been found to have superior oxidation resistance to the melted one. The oxidation scale of the former was suggested to be adhesive, for example, owing to the presence of fine alumina particulates and/or pores which contribute to pegs. The fine alumina particulates were developed by breaking up of the oxide layer along prior particle boundaries during the reactive-sintering process.

著者

山口 正剛

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.72, no.9, pp.657-666, 2008 (Released:2008-09-01)

参考文献数

20

被引用文献数

10 37

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The microscopic mechanism of the grain boundary embrittlement in metals by solute segregation has been not well understood for many years. From first-principles calculations, we show here that the calculated cohesive energy (2γint) of bcc iron Σ3(111) symmetrical tilt grain boundary is reduced by the segregation of sulfur (S) or phosphorous (P), while it is increased by the segregation of boron (B) or carbon (C). The rate of the decrease/increase in the 2γint was excellently proportional to the experimental ductile-to-brittle transition temparature (DBTT) shift with increasing segregation; this demonstrates that the grain boundary embrittlement is governed by the change in the 2γint.

著者

杉岡 奈穂子 北田 正弘 西嶋 雅彦

出版者

公益社団法人 日本金属学会

雑誌

日本金屬學會誌 (ISSN:00214876)

巻号頁・発行日

vol.77, no.5, pp.185-191, 2013-05-01

参考文献数

15

被引用文献数

2

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&nbsp;&nbsp;The metallurgical microstructure and mechanical properties of the spear blade manufactured in the Edo period have been investigated. The purpose of this work is to obtain metallographic data of the spear blade, and to clarify the manufacturing technique of the spear blade. The specimen examined was estimated to have been made from the end of the Muromachi period to the Edo period and has the signature of <i>Shinano-no-Kami Minamoto Takamichi</i>. The spear is 31 cm in length and 10.7 mm in maximum width. The metallurgical microstructure and nonmetallic inclusions of the spear blade are observed using an optical microscope. The carbon concentration is determined by chemical analysis. To evaluate the hardness, micro Vickers hardness (<i>H</i>_mv) is used. The microstructure is observed using an optical microscope and a scanning electron microscope (SEM). The concentration of nonmetallic inclusions is obtained by electron dispersive X-ray analysis (EDS).<br> &nbsp;&nbsp; A cross-sectional image of the spear after chemical etching shows a metal flow pattern formed by deformation, possibly created by hammering. The striped structure of layers of two types of steel containing different carbon contents stacked on top of each other was observed. The bright areas after etching corresponded to the edges and ridges of the spear, which were cooled rapidly, forming the martensite structure. The other dark areas consist of pearlite and &alpha;-Fe (ferrite) grains. Optical micrographs of near-edge areas contain pearlite and martensite grains, and core areas contain pearlite and &alpha;-Fe grains. The nonmetallic inclusions in the core steel consist of a few metal oxide particles and a glass matrix. There are Fe-Ti oxide grains in the glass matrix, and an unknown oxide particle adhering on the Fe-Ti oxide grain surface was also observed.<br>

著者

桐野 文良 北田 正弘

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.79, no.2, pp.57-63, 2015

被引用文献数

3

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&nbsp;&nbsp;The microstructures of a corrosion layer formed on the surface of two Japanese oldest coins, <i>Wadoukaichin</i> (surface color: dark brown and green) were studied. Compositions of these coins are that main element is Cu and Sn and traces are Pb, Fe and As. X-ray diffraction patterns show that copper di-hydroxide (Cu(OH)₂ 2H₂O), Cu_1.81S and Cu₂O are detected on the surface corrosion layer of dark brown sample, and Cu₂(CO₃)(OH)₂ (malachite), Cu₃(CO₃)₂(OH)₂ (azurite) and Cu₂O are detected on the surface corrosion layer of green sample. Optical microscope images show that the surface corrosion layer of dark brown sample is porous, and blue and green grains on the brown layer are existed on that of green sample. From spectrographs of these grains, the peak wavelength of green grains is matched to that of malachite, but this of blue grains is shifted to long wavelength side of about 40 nm at azurite on an influence of trace contaminations. The corrosion layer has two layers, surface layer is plate-like texture, and under layer is aggregation microstructure from TEM observation. The crystal structure of these two layers is matched to azurite from the electron beam diffraction patterns.<br>

著者

北田 正弘 高妻 洋成 肥塚 隆保 建石 徹

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.79, no.2, pp.71-75, 2015

被引用文献数

6

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&nbsp;&nbsp;The mural of the <i>Takamatsuzuka</i> tumulus in Asuka, Nara prefecture, was painted in the 7-8th centuries. Red, green, blue, yellow, and black pigments are used in the mural. The microstructure of one of them, the red pigment, was described in the previous paper. In this study, the black pigment observed within the red pigment area has been investigated. An optical microscope, a scanning electron microscope, and a transmission electron microscope are utilized to examine the microstructure. Among the black particles, two different Fe compounds are observed. One is magnetite (Fe₃O₄) comprising small amounts of Ti, Al, and Mg, and the other is ilmenite (FeTiO₃) containing a small amount of Mg. In addition to the above compounds, an oxide particle containing Zr is also observed.<br>

著者

齋藤 繁 黒川 一哉 林 重成 高島 敏行 成田 敏夫

出版者

日本金属学会

雑誌

日本金屬學會誌 = Journal of the Japan Institute of Metals (ISSN:00214876)

巻号頁・発行日

vol.71, no.8, pp.608-614, 2007-08-01

被引用文献数

3

著者

長部 吾郎

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.80, no.7, pp.396-405, 2016 (Released:2016-06-25)

参考文献数

24

被引用文献数

5

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By using the CT-OP (Controlled Over-Pressure) sintering furnace, Sumitomo Electric (SEI) succeeded in improving various characteristics such as critical current and mechanical properties of Ag sheath Bi-2223 wire commercialized as DI-BSCCO. Recently, SEI has developed and commercialized high strength DI-BSCCO Type HT-NX wire reinforced with the Ni alloy tapes and has applied the residual axial compression after lamination. The critical tensile stress of Type HT-NX has reached 400 MPa at 77 K. For high field magnetic application such as NMR using Bi-2223 based superconducting wire reinforced with Ni alloy tapes is highly expected.

著者

横川 忠晴 谷 月峰 崔 傳勇 小泉 裕 藤岡 順三 原田 広史 福田 正 三橋 章

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.74, no.3, pp.221-225, 2010 (Released:2010-03-01)

参考文献数

18

被引用文献数

1 3

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New kinds of cast and wrought (C & W) Ni-Co base superalloys (TMW alloys) have been developed based on the innovative concept of combining two kinds of γ-γ′ two-phase alloys, Ni-base and Co-base alloys, for the applications of turbine disks and high-pressure compressor blades. The results based on testing 20 kg ingots indicate that TMW alloys show excellent high temperature strength and formability, may provide 50°C temperature advantage in 630 MPa/100 h creep performance over C & W alloy U720Li.    In this paper, we report our new results on the full-scale pancakes manufactured through the C & W process for real components. The results indicate that TMW alloys had good process-ability in the ingot making and forging into disk pancakes. Pancake disks with fine grain size of about 10 μm were successfully obtained for TMW alloys. TMW alloys provide 58°C to 76°C temperature advantages in 0.2% creep strain life under the 630 MPa condition, over alloy U720Li.

著者

田口 智子 桐野 文良

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.79, no.10, pp.485-490, 2015 (Released:2015-10-01)

参考文献数

10

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Silver coins, such as mameitagin, which were used in the Edo period, were composed of a silver and copper alloy. In case the mameitagin casting was performed with low silver concentration, traditional metal works technique called iroage was performed on the coin to elute the copper from the alloy and produce an Ag-rich layer on the surface. In a previous study, we reproduced the iroage treatment on an Ag-Cu alloy using umezu (plum vinegar) as the treatment liquid and clarified that citric acid, malic acid and sodium chloride that are the main constituents of umezu, elute copper in the treatment liquid. In this study, the iroage treatment on Ag-Cu alloys was performed under various conditions to clarify the effect of different treatment conditions. The silver concentration of the Ag-Cu alloy samples used in this study were 75%, 45%, and 15%, and the color, surface structure, and silver concentration before and after treatment were investigated by spectrophotometry, scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS), respectively. First, the iroage treatment was performed by varying the immersion time in the treatment liquid. The results show that the copper elution velocity differed depending on Ag concentration in the samples. The treatment liquid temperature affected the amount of copper eluted. The percentage of umezu in the treatment solution did not affect the elution amount of copper. The iroage treatment was performed several times in the samples, and the EDS analysis showed that Ag concentration widely varied after treatment. The results suggest that the surface conditions of the repeatedly treated samples affected the copper elution.

著者

北田 正弘 高妻 洋成 建石 徹

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.79, no.8, pp.404-412, 2015 (Released:2015-08-01)

参考文献数

15

被引用文献数

2 4

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The Takamatsuzuka tumulus was constructed in the 7th to 8th centuries at Asuka in Nara prefecture. The mural and wall surfaces are soiled and deteriorated by rainwater, mold, and other causes. The mural is painted on the stone wall that is coated with stucco. The stone walls are jointed with masonry joint stucco. The purpose of this investigation is to clarify the composition, crystal structure, and other material factors of the surface contaminant layer on the joint stucco. An X-ray computer tomography, an X-ray diffractometer, a scanning electron microscope, and a transmission electron microscope are utilized to examine the microstructure. The contaminant layer thickness is 0.2-0.3 mm. Kaolinite, muscovite, montmorillonite, hematite and a few silicates are detected from the contaminant layer. The compounds detected are constituents of soil-like clay, and most of them contain Fe. By transmission electron microscopy observation, the contaminant layer is found to consist of fine mineral grains, as mentioned above, most of which are acicular. The acicular grain size is approximately 0.2-1 μm in length and 0.015-0.2 μm in width. The grains are in a row parallel to the layer surface. The hematite grains are circular with diameters of 15-250 nm. In addition, iron titanate is observed. The yellowish brown color of the stucco surface is mainly due to iron ions contained in the above-mentioned compounds. It is thought that the grains deposited on the stucco surface from colloidal-like water containing the above-mentioned fine grains.

著者

鈴木 清一

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.77, no.7, pp.268-275, 2013 (Released:2013-07-01)

参考文献数

10

被引用文献数

4 6

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Transmission-EBSD (t-EBSD) method is proposed as a new method for nano-scale microstructures analysis of materials. t-EBSD uses TEM thin foil specimen. Electrons transmitted through the specimen form EBSD patterns. A EBSD detector used for standard EBSD (s-EBSD) is used to acquire these t-EBSD patterns. The patterns are indexed in the same manner as s-EBSD to get crystal orientation. The conditions to get good t-EBSD patterns, formation of t-EBSD patterns and spatial resolution of this method are studied in this paper.    Specimen thickness affects seriously to the results of orientation mapping by t-EBSD. It is confirmed that t-EBSD patterns are formed at the bottom layer of the specimen. If the specimen is very thin, the patterns become very weak and noisy. If the specimen becomes thicker, t-EBSD patterns lose its contrast and sometimes patterns become weak with reverse contrast bands. This means that total thickness of the specimen is important for t-EBSD method, but overlapped grains look not so big problem to get t-EBSD patterns.    Electron beam spread in the specimen is reduced due to thin foil specimen, and it improves spatial resolution of EBSD orientation map. It is confirmed that it can achieve about 10 nm spatial resolution and about 30 nm size grains can be detected with reasonable thickness specimen.

著者

田中 眞奈子 北田 正弘

出版者

日本金属学会

雑誌

日本金屬學會誌 (ISSN:00214876)

巻号頁・発行日

vol.76, no.8, pp.489-495, 2012-08-01

参考文献数

15

著者

進藤 裕英 小堀 智之 堀口 勝三 山田 英一 中嶋 秀夫 辻 博史

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.59, no.8, pp.793-798, 1995 (Released:2008-04-04)

参考文献数

12

被引用文献数

2

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This paper discusses fracture toughness and temperature rise for JJ1 austenitic stainless steel forged plate at liquid helium temperature for fusion reactor magnets of next generation. Elastic-plastic fracture toughness (JIC) testing was conducted in general accordance with ASTM standards E813-81 and E813-87, and unloading-compliance technique was applied using compact specimens 25.0 mm and 12.5 mm thick. Thermocouples were used to measure the temperature rise near the crack tip. The effects of specimen size and side-groove on the cryogenic fracture properties of this alloy are examined. Examination of the fracture surface of CT specimens by scanning electron microscopy showed ductile failure by microvoid coalescence. The effect of inclusion on fracture mechanics parameters (JQ, JIC) is also discussed using energy dispersive X-ray analyser.

著者

赤堀 俊和 新家 光雄 原田 雅章 武田 淳仁 戸田 裕之 桂 成基 竹内 力 福井 壽男

出版者

日本金属学会

雑誌

日本金屬學會誌 = Journal of the Japan Institute of Metals (ISSN:00214876)

巻号頁・発行日

vol.69, no.1, pp.96-102, 2005-01-20

被引用文献数

1