巻号一覧
24 巻, 5 号
選択された号の論文の6件中1～6を表示しています
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木下 実, 寺井 良平1977 年 24 巻 5 号 p. 135-141
発行日: 1977/07/25
公開日: 2009/12/04
ジャーナル フリーPressure sintering was carried out with atomized iron powder in graphite die at 600°C to 1150°C under the pressure of 50 to 550 kg/cm2. The densification behavior of the powder compact and the microstructure of the sintered body were investigated.
Under a constant pressure, maximum density was obtained by sintering at 850° or 900°C. When sintered at 900°C under 550 kg/cm2, density reached about 7.81 g/cm3, the highest value attained in this investigation. As the pressure increased, the temperature at which densification started decreased and the density increased. Carburization was observed in the surface part of the compact when sintered above 950°C.
In the early stage of pressure-sintering, plastic deformation of the powder particles was thought to be a predominant densification mechanism, and from the densification behavior, the yield stress values of the iron particles were estimated at the temperature range from 600°C to 900°C. Diffusion mechanisms seemed to become operative in the later stage.抄録全体を表示PDF形式でダウンロード (3395K) -
明智 清明, 原 善四郎1977 年 24 巻 5 号 p. 142-146
発行日: 1977/07/25
公開日: 2009/12/04
ジャーナル フリーSquare bars of steel-fibre reinforced aluminium were made by a resistance sintering process, using atomized and mixer-treated aluminium powders and short steel fibres. The mechanical properties and conditions of fibre-matrix interface, and the relation between them in the sintered bars were investigated. The following results have been obtained. (1) Depending on the diameter and volume fraction of steel fibres, there exists a suitable input power range in the resistance sintering process so that the fibre-metal composite bars have the highest tensile strength and elongation. Even in the same range, with higher set-up effective current and shorter electric charging time, the mechanical properties become higher. (2) With the input power less than the suitable range, the density is low and the adhesion between fibre and matrix is weak. In tensile tests the fibres are pulled out without breaking. (3) With the input power above the suitable range, metallic compounds are formed along the fibre-matrix interface and the tensile strength and elongation tend to decrease with increasing input power. The tendency is more remarkable for smaller diameter fibres.抄録全体を表示PDF形式でダウンロード (1864K) -
斎藤 総一郎, 岡田 元秀, 山口 喬1977 年 24 巻 5 号 p. 147-151
発行日: 1977/07/25
公開日: 2009/05/22
ジャーナル フリーEffects of carbide additives on the interaction between liquid copper and WC-Co alloys containing 20% Co have been studied at 1120°C by means of EPMA and optical microscopy.
Addition of TaC or TiC checked the wetting of liquid copper on cemented carbide and the structures of diffusion layers were influenced markedly by the carbide addition with a more pronounced effect for TiC. Thus, the development of cobalt solid solution at the liquid copper/cemented carbide interface was checked by the carbide additives. These findings have been successfully interpreted as due to the poor wettability of liquid copper and also of cobalt solid solution to TaC and TiC.抄録全体を表示PDF形式でダウンロード (1635K) -
山下 邦男, 宮内 克己, 渡辺 薫樹, 戸田 堯三1977 年 24 巻 5 号 p. 152-156
発行日: 1977/07/25
公開日: 2009/12/04
ジャーナル フリーOptical transmittance, grain size and ferroelectric properties are measured along the radial direction of large-scale (40-50 mmφ) PLZT-7.6/70/30 ceramics in order to evaluate the homogeneity in a plate. Ferro-antiferroelectric transition temperatures (Th) are measured by the pyroelectric method. In addition, compositional fluctuations in a PLZT plate are discussed by measuring the variation of Th. Results indicate that grain size (Gs), coercive field (Ec) and remanent polarization (Pr) are uniform within experimental errors through large-scale specimens. Optical transmittance is also uniform except at the fringe of a plate. Moreover, the optical transmittance is found to be sensitive to hot-pressing conditions and inhomogeneities in a plate, while Ec and Pr are not sensitive. Consequently, the measurement of the optical transmittance is effective in the evaluation of homogeneities in large-scale PLZT plates. Transition temperature variation indicates that the fluctuation of Zr concentration through a ceramic plate is 0.04 mol % by assuming La distribution to be uniform; the fluctuation of La concentration is 0.01 at % by assuming a uniform Zr distribution.抄録全体を表示PDF形式でダウンロード (324K) -
Osamu Yamaguchi, Hitoshi Tonami, Tadahiro Hayashi, Kiyoshi Shimizu1977 年 24 巻 5 号 p. 157-161
発行日: 1977/07/25
公開日: 2009/05/22
ジャーナル フリーThe kinetics of the initial sintering and grain growth of magnesium oxide (MgO) prepared by the alkoxy-method were investigated by means of dilatometry, electron microscopy and the measurement of isothermal shrinkage. The obtained results are summarized as follows.
(1) The initial sintering kinetics of MgO were determined from 1000 to 1200°C. The sintering process was governed by the volume diffusion of oxygen ions which was represented by D=2.54×10-5exp(-64, 000/RT)cm2/sec.
(2) The grain growth of MgO was represented by the expression of G2-G02=kt, and the temperature dependence of k was given by k=3.3×10-3 exp(-77, 000/RT)em2/sec.抄録全体を表示PDF形式でダウンロード (1420K) -
本田 忠敏, 黒木 英憲1977 年 24 巻 5 号 p. 162-165
発行日: 1977/07/25
公開日: 2009/05/22
ジャーナル フリーThe deformation and rupture behavior of tensile specimens of iron compact were observed on the polished surface, on the sectional area and on the fracture surface.
On the polished surface, cracks developed into a network structure. But most of these cracks did not propagate into the specimens, and remained as grooves within a thin surface layer.
In highly sintered specimens, pores expanded and coalesced as observed in the case of the usual ductile fracture of cast materials, in other words, internal necking took place.
In lightly sintered specimens, welded necks at the particle boundaries were broken, and the particles themselves were not deformed. Though, this type of fracture appeared to be brittle by light microscopy, it was recognized to be ductile by a detailed observation through a scanning electron microscope.
The surface cracking and the internal necking were considered to be due to less constraint on the free surface than in the interior.抄録全体を表示PDF形式でダウンロード (3056K)
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