著者

東 泰助 井上 誠 小野木 伯薫 横田 勝 村田 安規 中平 敦

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.59, no.6, pp.418-422, 2010

被引用文献数

3 1

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The development of low melting temperature coating materials for brazing diamonds was attempted for diamonds wire saw for slicing single crystal silicon.The diamonds wire saw was made by brazing diamonds on SUS-304 wire with high strength for the sawing equipments. Since the degradation of SUS-304 wire was generally generated at higher temperature over 600°C, the high performance coating materials, composed of 47.5 wt.%Ag-25.5 wt.%Cu-27.0 wt.%Sn based materials, was developed by addition of Ni into them to improve the brittleness for SUS-304 wire. These results suggested that the coating material of (47.5 wt.%Ag-25.5 wt.%Cu-27.0 wt.%Sn)-1 wt.%Ni was the suitable brazing of the diamonds SUS-304 wire for sawing equipments.

著者

小笠原 正弘 平尾 孝 藤田 静雄

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.64, no.5, pp.405-409, 2015

著者

島村 佳伸 奥田 尚紀 東郷 敬一郎 荒木 弘安

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.56, no.5, pp.393-398, 2007

被引用文献数

7 7

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It is well known that carbon nanofillers (CNFs) enhance the stiffness, electric conductivity and thermal conductivity of polymers. Alignment of carbon nanofillers in polymer is expected to increase the performances in the aligned direction. Several papers have reported that applying alternating electric field to a liquid suspension including CNFs causes alignment of CNFs in the electric field direction. Only a few papers have reported the fabrication of nanostructurally controlled composites by using AC field, but the conditions to let CNFs align have not been investigated. In this study, unidirectionally aligned carbon nanofiller/epoxy composite was fabricated under AC electric field, and the alignment of CNFs was in-situ observed during fabrication by using an optical microscope. Then, the effects of applied voltage, frequency and the weight fraction of CNFs on nanostructure were investigated. As a result, it is found that CNFs in uncured epoxy resin align in the AC electric field and form a chain-like network, and that in the end the network structure is hold with cured epoxy. It is also shown that the applied voltage and weight fraction affect the morphology of the network. Furthermore, the network morphology was quantified by using texture analysis. Local homogeneity in the longitudinal and transverse directions of the AC electric field was used. It is found that there is strong relationship between the changes of local homogeneity and network morphology.

著者

臺丸谷 政志 小林 秀敏

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.60, no.7, pp.668-673, 2011

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The Japanese sword is interesting not only from the viewpoint of traditional crafts of arts, but also from the aspect of modern science and technology because the way of making and its functionality as a weapon are really consistent with modern science. The present study is concerned with the joint between <i>tohshin</i> (blade) and <i>tsuka</i> (hilt) of the sword. Only one <i>mekugi-take</i> (retaining peg made of bamboo) with about 5mm in diameter holds <i>Nakago</i> (tang) in the hilt. However the slender <i>mekugi</i> might not be broken, even in the case of violent sword-fighting. This fact has been historically demonstrated in many battles by Japanese swords. In this study, using a Japanese sword model, it is examined theoretically and experimentally why a <i>mekugi</i> used in Japanese swords might not be broken from the viewpoint of impact engineering. Consequently, it is presumed that such a strong force as breaking <i>mekugi-take</i> does not act on it, because of the location of <i>mekugi-ana</i> (a hole for <i>mekugi</i>) in the tang, which has been made by following the traditional code of swordsmiths.

著者

攝津 暢浩 高橋 学 松下 正史 岡部 永年

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.61, no.6, pp.530-536, 2012

被引用文献数

6

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We investigate the mechanical strength of ceramic/metal composites subjected to cyclic thermal loading. First, test samples of Cu/AlN systems are prepared via brazing. Next, short-term thermal cycle tests (25, 50, and 100cycles) are conducted at temperatures ranging from -40 to 125°C. Four-point bending tests are conducted to evaluate the residual strength. Further, thermal stress analysis is performed using the finite element method in order to examine the thermal stress behaviors during cyclic heating. The results reveal that the residual strength increases during 0∼20cycles because of residual thermal stress relaxation. This relaxation is generated by the cyclic softening of the metals owing to combined hardening. In contrast, relatively long-term thermal cycling (20∼100cycles) reduces the residual strength owing to damage growth to AlN. The AlN plates exhibit variability in residual strength, and the distribution of the residual strength for each cycle number conforms to the two-parameter Weibull curve. The variability in residual strength increases with the cycle number, and it is attributed to variabilities in the pre-existing crack size and damage accumulation. We conclude that the residual strength of the Cu/AlN composites depends on the thermal stress behavior and damage growth to the AlN plates.

著者

西川 幸宏 太田 直秀 小升 雄一朗 高橋 雅興

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.60, no.1, pp.29-34, 2011

被引用文献数

7

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Three-dimensional real-space images of the carbon fiber (CF)/polymer composites were obtained by a high-contrast X-ray computerized tomography (CT). Since both CF and polymers do not include heavy atoms, CF has not been supposed to be suitable to X-ray CT observation. In this study, we used the X-ray CT apparatus which is designed to enhance the contrast of the materials consisting only of light-weight atoms. Besides the usage of the appropriate apparatus, the experimental conditions were found to be important : cutting the sample into a thin rod, and obtaining sufficient number of projections. In our case, we used 1mm × 1mm × 4mm sample, and 720 projections with 0.25 degree intervals in order to obtain the 3μm voxel resolution in the reconstructed three-dimensional images. Eventually, each CF in polystyrene was clearly visualized in three dimensions.

著者

上田 敏郎 島村 佳伸 東郷 敬一郎 藤井 朋之 岡島 いづみ 平松 正敬 佐古 猛

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.59, no.12, pp.964-969, 2010

被引用文献数

2 5

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Carbon-fiber reinforced epoxy was decomposed using subcritical water and supercritical methanol to reclaim carbon fibers. The tensile strength of the reclaimed carbon fibers was measured. Then SEM observation, XPS, and Raman spectral analysis were conducted to elucidate the change of tensile strength caused by decomposition. The tensile strength decreased by 6% in the case of decomposition with supercritical methanol, and by 12~17% with subcritical water. The surfaces of reclaimed carbon fibers were resin-free. Decomposition did not affect the fiber surface and fracture surface morphology. Subsequent XPS analysis revealed that functional groups of the carbon fiber surface had been removed. Raman spectral analysis showed decreased graphitization of the carbon fiber surface. These results imply that the fracture toughness of the carbon fiber surface decreased because of breakage of carbon-carbon bonds in the carbon fibers as a result of decomposition.