巻号一覧
58 巻, 1 号
選択された号の論文の18件中1～18を表示しています
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麻生 節夫, 田上 道弘, 後藤 正治1994 年 58 巻 1 号 p. 1-7
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーThe liquidus surface phase diagram of the quaternary Fe-25%Cr-C-B system has been experimentally determined by using a thermal analysis technique, optical microscopy and X-ray diffraction. The liquidus surface for this system was constructed from five phases of M2B, M23(C, B)6, M7(C, B)3, γ and δ. Each phase formed four kinds of eutectic structures, that is, γ+M2B, γ+M23(C, B)6, γ+M7(C, B)3 and γ+M3(C, B), and three kinds of peritectic structures, that is, M2B+M23(C, B)6, M7(C, B)3+M23(C, B)6 and γ+δ. Additionally, M2B and M7(C, B)3 also solidified in a eutectic manner near the liquidus boundary between M2B and M7(C, B)3. The borides contain 7.0∼9.5 mass% boron and less than 0.3 mass% carbon. The stoichiometric boron concentration of M2B was about 8.9∼9.4 mass%, so it suggested the existence of lower boron boride than that of M2B. Carbon and boron concentrations of three types boro-carbides changed linearly, the maximum boron content of each boro-carbide was about 2.4 mass% in M7(C, B)3, about 2.2 mass% in M23(C, B)6 and about 3.3 mass% in M3(C, B). The microstructures along the pseudo-binary eutectic composition were constructed from one or two kinds of eutectic structures. That is, in the lower carbon content (higher boron content) side from the composition at a minimum temperature (1460 K) on the pseudo-binary eutectic line, γ+M2B solidified singly or together with γ+M23(C, B)6, while in the higher carbon side three eutectic types of γ+M23(C, B)6, γ+M2B and γ+M7(C, B)3 solidified separately or together with others.抄録全体を表示PDF形式でダウンロード (1457K) -
向後 保雄, 八田 博志, 香川 豊, 岸 輝雄1994 年 58 巻 1 号 p. 8-14
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーIn order to estimate the effect of transformation toughening (ΔK) in an anisotropic composite, the stress analysis approach for ΔK proposed by McMeeking et al., which is applicable only to isotropic materials, has been extended to anisotropic analysis. Numerical calculation is carried out for SiC whisker (SiCW) and ZrO2 reinforced glass matrix composites by considering the anisotropy induced by whisker alignment.
Bueckner’s weight function method is applied to this analysis. Though the weight function can originally be applied only to the isotropic case, it is extended to the anisotropic case in this study. Eshelby’s equivalent inclusion method is used for calculating elastic constants and transformation strain of the ZrO2 composite.
From calculations on a triple phase composite, consisting of SiCW, ZrO2 and glass matrix, it is found that the whisker enhances the transformation toughening. It is also expected that the transformation toughening acts almost independently with other toughening mechanisms, such as whisker bridging. The effect of anisotropy on toughening is also estimated for aligned SiCW in the triple phase composite. The results show that the perpendicular SiCW alignment with respect to the crack plane brings larger enhancement of the toughening effect than the parallel alignment, but the difference between them is not so large.抄録全体を表示PDF形式でダウンロード (718K) -
酒井 拓, 三浦 博巳, 村松 尚国1994 年 58 巻 1 号 p. 15-22
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーThe effect of small additions of Co on dynamic recrystallization (DRX) of Cu-Be alloys was studied by means of tensile testing and microstructural observation at 1123 K and at strain rates from 10−5 to 10−1 s−1. The high-temperature flow curves were scarcely affected by the addition of Co and, in contrast, the room-temperature hardness of the hot-deformed matrix are clearly dependent on it. Such age hardening took place more clearly during hot deformation compared with static annealing of the Cu-Be-Co alloys. On the other hand, cuboid-shaped inclusions existing only in the Cu-Be-Co alloys were identified as the (CoCu) Be intermetallic compound. Their growth rate is accelerated by hot deformation. DRX of the Cu-Be alloy was almost the same as that of pure Cu in the whole range of deformation condition, and also that of the Cu-Be-Co alloys only in the region of flow stresses higher than 50 MPa. In the lower stress region, DRX as well as the growth of (CoCu) Be particles took place simultaneously during deformation, leading to the evolution of finer DRX grain structures. It is concluded that the critical condition in which the Cu-Be-Co alloys change the DRX characteristics is Ds=Dlim. (Here Ds and Dlim are the stable DRX grain size and the final grain size stabilized by second phase particles, respectively.) When Ds<Dlim in the higher stress region, dynamic grains can be controlled by DRX, leading to Ds. Conversely, when Ds>Dlim in the lower stress region, they can be controlled by second phase particles, leading to Dlim.抄録全体を表示PDF形式でダウンロード (1676K) -
長谷川 信一, 小林 剛, 井出 邦和, 大河内 春乃, 長谷川 良佑1994 年 58 巻 1 号 p. 23-29
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーGraphite furnace atomic absorption spectrometry (GF-AAS) has been applied to the direct determination of trace amounts of Pb, Mn, and Co in the respective acidic solutions of high-purity zirconium and molybdenum. Platform atomization in a pyrolytically coated graphite tube permitted high sensitive and precise determination of Pb, Mn and Co in zirconium and that of Mn and Pb in molybdenum. However, graphite tube wall atomization using a sample solution modified with nickel nitrate was required for the determination of Co in molybdenum. When the weighed amount of the sample was 1 g, the limits of detection (3σ of blank values) were 0.12 ppm of Pb, 0.04 ppm of Mn and 0.07 ppm of Co for the zirconium sample, and 0.03 ppm of Pb, 0.05 ppm of Mn and 0.10 ppm of Co for the molybdenum sample. Moreover, the analytical values obtained for Pb, Mn and Co in the JAERI CRM Z11-Z13 zircaloys showed good agreement with their certified values. The proposed analytical procedure could be applied to rapid analyses of other refractory metal samples by using the sample solutions without pretreatments such as separation of the carbide-forming matrix elements.抄録全体を表示PDF形式でダウンロード (637K) -
中江 秀雄, 山内 崇1994 年 58 巻 1 号 p. 30-36
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーUnidirectional solidification experiments were conducted on high purity iron-carbon alloys containing various amounts of sulphur or cerium in order to clarify the mechanism of spheroidization of graphite in cast iron. A self sealing method was used to prevent decarburization and oxidation of cerium. In the alloys containing 0.003 mass% sulphur or 0.2 mass% cerium, the graphite flakes at the interface were completely covered with austenite. At this time, the intergraphite spacing decreased suddenly at a critical solidification rate of 4 mm/h. In the alloys containing more sulphur (>0.006 mass%), the graphite flakes at the interface protruded into the liquid phase. In this case, there was a sudden increase in the intergraphite spacing at a solidification rate of 4 mm/h. It is considered that the change in the morphology at the interface was caused by lowering the graphite/liquid interfacial energy. The sudden increase in the intergraphite spacing was caused by the limiting effect of the adsorbed sulphur on the branching of graphite flakes. In addition, an equilibrium interface morphology was achieved by holding the furnace stationary for 5 h.抄録全体を表示PDF形式でダウンロード (1771K) -
山崎 裕之, 大野 篤美, 清水 亨1994 年 58 巻 1 号 p. 37-42
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーStellite No. 1 alloy has been successfully cast into a strip and rods with rectangular and triangular cross-sectional profiles by the vertical type Ohno Continuous Casting (OCC) process. Casting conditions have been examined to produce products with these shapes. It was found that by bringing the solid-liquid interface to the mold exit as close as possible, edged products of small dimension could be cast. However, cooling of the rod during casting must be controlled by changing the cooling nozzle positions according to the geometric shapes of the rods in order to obtain a straight solid-liquid interface profile and to avoid edge tearing of the cast products.抄録全体を表示PDF形式でダウンロード (884K) -
福本 昌宏, 恒川 浩一, 梅本 実, 岡根 功1994 年 58 巻 1 号 p. 43-49
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーComposite powder materials possess a potential to fabricate the high performance structural coatings instead of the conventional mechanically mixing powders. In the many composite powder making processes, machanical alloying (MA) process enables to obtain the homogeneous microtructure of metal/ceramic materials system. In the DC plasma spraying of metal/ceramic MA composite powders, separation phenomena of ceramic phase from metal phase has been recognized.
In this study, metal/ceramic MA composite powders were made by using the ceramic making original elements as the starting material and these MA powders were plasma sprayed. Possibility of fabrication of ceramic particles dispersed composite coatings, by the inter-diffusion of these starting elements, was investigated.
The main results obtained in this work are summarized as follows:
(1) Separation was recognized even in the Cu/TiC MA powder material system, which had good wettability between metal and ceramic materials.
(2) Separation is basically caused in MA composite powder materials under the spraying conditions of high power level, on which both materials can be fully melted.
(3) TiC dispersed homogeneous coating was made by DC plasma spraying of Cu/Ti/C MA powder.
(4) Coating made from MA powders showed slightly higher hardness with less scattering compared with that made from the conventional powders, because of the homogeneously dispersed structures.抄録全体を表示PDF形式でダウンロード (982K) -
福本 昌宏, 根来 健一, 岡根 功, 鬼頭 昌之, 深見 慎二1994 年 58 巻 1 号 p. 50-54
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーIn order to fabricate SOFC fuel electrodes, which were composed of a fine homogeneous microstructure of Ni/YSZ, plasma spraying of Ni/YSZ mechanically alloyed composite powders was carried out. To perform this, the oxidation heat treatments of the MA powder were introduced. Some properties, for example, conductivity and gas permeability, of the coatings obtained were measured, and the applicability of MA powders to the fuel electrodes was evaluated.
The results obtained are summarized as follows:
(1) The oxidation heat treatments to the MA powders were seemed to be effective in both suppression of the separation between Ni and YSZ and maintenance of the initial composition of the powder. Fine-microstructure fuel electrodes were fabricated by the spraying of pre-oxidized MA powders.
(2) The relation between conductivity of the coating and reduction time at 1273 K was measured. In the coating made from 72 ks MA and 50%Ni contained powders, as the reduction time increased the conductivity increased gradually, and the conductivity of this coating reached the maximum value of 90 kS/m finally.
(3) The gas permeability of the coatings made from MA powders were smaller than that of the coatings made from conventional agglomerated powders. This could be improved by controlling the process parameters such as spraying conditions.抄録全体を表示PDF形式でダウンロード (1292K) -
東 正則, 内田 満夫1994 年 58 巻 1 号 p. 55-61
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーCast Fe-Si-Al alloys containing 0.5%Ti, 0∼0.06%C, 0.2%rare earth metal, were prepared using a 10-kg vaccum induction furnace. Fe-Si-Al alloy cores for magnetic recording head were produced by grinding from those alloys which were hot-rolled and annealed at 900∼1100°C. In this paper, the effect of grain size on chipping resistance in rough cutting, groove grinding and fine cutting of head-cores process is studied. The results obtained are as follows. \ding”C0 The methods to obtain a fine grain size of Fe-Si-Al alloy are “hot-rolling” and “adding the minimum quantity of inhibiting grain-growth elements C, Ti, M. M. to alloy”. The former is the best method to obtain alloys with fine grains. \ding”C1 The larger the grain size in Fe-Si-Al alloys, the more the number of chips increases. \ding”C2 Both the depth and the number of chips are larger in cast alloys than hot-rolled and annealed alloys. \ding”C3 Alloys with fine grains are obtained by the adding two elements (Ti & C) to alloys rather than adding one element (Ti or C).抄録全体を表示PDF形式でダウンロード (830K) -
高橋 和雄, 下屋敷 重広, 横田 憲克1994 年 58 巻 1 号 p. 62-68
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーThe frictional properties of three kinds of coating materials, Cr3C2+Cr2O3, Cr3C2 and Cr2O3, on Type 304 stainless steel were tested for sliding parts of fast breeder reactor components. The temperature dependence of the kinetic friction coefficient and the continuity of lubricants were tested for each coating in sodium with 5 mass ppm of oxygen at temperatures of 473-823 K.
The kinetic friction coefficients of all these materials were about 0.4 when the sodium temperature was below 683 K and were reduced to 0.2 at higher sodium temperatures. This was because NaCrO2 was formed on the coating surfaces and worked as a good lubricant. Its lubricating property was best in the Cr3C2+Cr2O3 coating, followed by the Cr3C2 and Cr2O3 coatings in order. In the Cr3C2+Cr2O3 coating, a NaCrO2 was formed from Cr2O3 in the interior of the coated layer, and was supplied on the sliding surface continuously. In Cr3C2 coating, very thin NaCrO2 layer was formed, but in Cr2O3 a very thick and brittle NaCrO2 layer was formed and was easily broken away from the surface during sliding.抄録全体を表示PDF形式でダウンロード (2123K) -
原田 秀文, 工道 幸嗣, 井上 保雄, 土取 功1994 年 58 巻 1 号 p. 69-77
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーAn AC8A aluminum alloy matrix composite reinforced with highly crystallized potassium titanate whisker having a crystallite size of 76 nm was fabricated by squeeze casting. Heat hardening behavior and mechanical properties were examined on the obtained composites whose Mg contents in the matrix were from 0.7 to 1.9 mass%.
The Mg content and hardness of the composite were uniform at any locations. The composite whose Mg content in the matrix were 1.7 mass% solutionized at 803 K showed the highest strength value at room temperature and 573 K, respectively. And the Young’s modulus was as high as 138 GPa. The decrease in strength during exposure at up to 573 K was not observed. In particular, the properties of the obtained composite were found to be useful for the elevated temperature materials.抄録全体を表示PDF形式でダウンロード (1580K) -
永友 賢治, 菅沼 克昭1994 年 58 巻 1 号 p. 78-84
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーAluminum borate whisker preforms were prepared without any binder by sintering and 6061 aluminum alloy matrix composites were fabricated by squeeze casting. Aluminum borate whiskers partly transformed to α phase alumina during sintering. Whiskers in a preform tightly bound each other at a contacting point and a thin amorphous layer covering whiskers was observed. The 6061 aluminum alloy composites fabricated from these preforms exhibited higher tensile strength than the composites with sillica binder from room temperature to high temperature. The reaction between the whiskers and 6061 matrix occurred at about 790 K and the reaction product was γ-alumina.抄録全体を表示PDF形式でダウンロード (2752K) -
小野 修二, 斉藤 正洋, 松尾 信太郎1994 年 58 巻 1 号 p. 85-90
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーRecently, new high strength 18%Cr cast stainless steel has been put into practical use for marine propellers. The stress corrosion cracking resistance of this steel in sea water was compared with that of other cast stainless steels such as martensitic cast stainless steel.
The results are summarized as follows:
(1) No crack is found regardless of the heat treatment condition of high strength 18%Cr cast stainless steel (C≤0.04), after the stress corrosion cracking test was carried out under cathodic protection with zinc.
(2) The stress corrosion cracking resistance of this steel in sea water is as superior as that of two-phase cast stainless steel.
(3) In order to maintain the superior stress corrosion cracking resistance of this steel, the upper limit of carbon content should be controlled as low as possible and strong cold working should be avoided.抄録全体を表示PDF形式でダウンロード (1077K) -
本田 紘一, 香川 豊1994 年 58 巻 1 号 p. 91-97
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーThe interfacial shear stress transfer mechanism of fiber-matrix sliding interfaces in SiC fiber-reinforced Ti matrix composites have been studied using both the push-out and pull-out tests. The interfacial shear sliding stress (τs) is expressed as the form of τs=μ(σT+σR+σP), where μ is the coefficient of sliding friction at the sliding interface and σT, σR, σP, respectively, are the thermal residual stress at the fiber radial-direction, the interfacial roughness induced stress and the stress occurred by the Poisson’s ratio difference between fiber and matrix.
Quantitative evaluations of the μ, σT, σR, σP and their contribution to the shear sliding stress can become possible by the use of both the push-out and pull-out tests. In case of the SiC(SCS-6) fiber-reinforced commercially-pure Ti matrix composites, τs=30∼50 MPa, μ≈0.2. It was confirmed that the thermal residual stress (σT), which was introduced at the fiber-matrix interface during the cooling process from the processing temperature, plays a major role in the generation of fiber radial-direction stresses during the shear sliding process of the interface.抄録全体を表示PDF形式でダウンロード (1089K) -
松崎 祐司, 藤岡 順三, 吉川 孝男1994 年 58 巻 1 号 p. 98-105
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーFunctionally Gradient Materials (FGM) promise to be used for advanced thermal barrier coatings in gas turbine engines and for heat insulation systems in structural components in hypersonic aircraft. The damage mode associated with inelastic deformation of FGM in elevated thermal cycling conditions, however, must be clarified for the practical service environment use. The work reported herein describes the results of numerical experiments on the thermomechanical response of the FGM using Finite Element Methods (FEM) wherein the nonlinear inelasticity of Hastelloy X was utilized for the analysis model. Further experiments were conducted to illustrate the effects of thermal and mechanical properties of FGM constituent materials on the inelastic behavior in thermal cycling environments. The compressive inelastic strain at the hot side surface of FGM in the heat-up cycle causes a significant residual tensile stress generation after the cool-down cycle. Using ceramics with a low thermal expansion coefficient enables the residual tensile stress reduction owing to the less inelastic compressive deformation at the hot side surface of FGM in the heat-up cycle. FGM compositional distribution is less effective for controlling the residual stress. The effects of elastic modulus of the FGM constituent materials were also investigated.抄録全体を表示PDF形式でダウンロード (1293K) -
牧野 彰宏, 新野 さゆり, 井上 明久, 増本 健1994 年 58 巻 1 号 p. 106-112
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーA mostly single bcc phase with nanoscale grain size of about 10 nm was found to be formed by annealing Fe-Nb-B sputtered amorphous films. The bcc Fe-Nb-B alloy films with solute contents of 6.5 to 9.5 at%Nb and 9.5 to 15 at%B annealed at 923 K for 3.6 ks exhibit good soft magnetic properties. Especially, a high permeability (μ) of 4000 at 1 MHz combined with high saturation magnetization (Bs) of 1.55 T was obtained for a Fe81.1Nb7.5B11.4 sputtered film. The good soft magnetic properties seem to result from the decrease in apparent magnetic anisotropy by formation of the nanocrystalline bcc structure and by reduction of magnetostriction due to dissoluiton of Nb and B into the bcc phase. Amorphous regions surrounding bcc grains were observed in the high-resolution electron micrograph for a Fe79.5Nb7.3B13.2 film annealed for 3.6 ks at 923 K. It is presumed by analysis of the temperature dependence of the grain size and magnetostriction that the thermal stability of the residual amorphous phase increases with the increases of solute elements discharged from the bcc grains.抄録全体を表示PDF形式でダウンロード (1667K) -
池宮 範人, 山田 浩司, 原 茂太1994 年 58 巻 1 号 p. 113-114
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーPDF形式でダウンロード (302K) -
鈴木 俊夫, 茂木 徹一, 佐久田 博司, 栗林 一彦1994 年 58 巻 1 号 p. 115-116
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーPDF形式でダウンロード (406K)
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