巻号一覧
58 巻, 6 号
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茂中 尚登, 布施 元正, 松本 斉, 森 勉1994 年 58 巻 6 号 p. 585-590
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーBubble formation and growth on grain boundaries under Ar ion implantation were investigated using Cu bicrystals which have symmetric [0, 1, 1] tilt boundaries. Density and growth rate of bubbles increase with grain boundary (GB) energy which is determined from the lenticular shape of bubbles on the grain boundary. These results show that the fluence of Ar as solutes into GB increases with GB energy increase, because the solute is easy to precipitate on high energy GB. On the other hand point defect inflow to the GB does not depend on GB energy. The origin of the difference of these phenomena between solutes and point defects is thought to be as follows: Solute atoms remain on the GB but point defects disappear when they are absorbed on the GB.抄録全体を表示PDF形式でダウンロード (1319K) -
田村 俊之, 松本 要, 田中 靖三1994 年 58 巻 6 号 p. 591-595
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーIt is well known that, in Nb-Ti superconducting wire, critical current density, Jc, in external magnetic field is crucially controlled by the α-Ti precipitates. Therefore, clarifying its dependence on the heat treatment condition is important to increase Jc still more. In the present study, the characteristic of Jc during heat treatment is investigated using copper-sheathed Nb-46.5 mass%Ti monofilamentary wires which are cold-worked at ε=6.29 prior to the heat treatment. The heat treatment procedure is performed isothermally at temperatures between 300 and 500°C. The precipitation behavior of α-Ti phase against heat treatment conditions is estimated assuming that Jc varies proportionally to the volume fraction of α-Ti precipitates. It is considered that α-Ti phase precipitates most vigorously around 400°C and that, after 1000 h treatment at 400°C, the volume fraction of the precipitated α-Ti reaches up to 20%. A T.T.T. diagram in the Nb-Ti system is also demonstrated based of the present results.抄録全体を表示PDF形式でダウンロード (1034K) -
吉川 貴士, 猪子 富久治1994 年 58 巻 6 号 p. 596-604
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーIn order to clarify the effect of active slip systems on the recrystallization along/near the grain boundaries, three kinds of 99.99 mass% copper bicrystal specimens, which have the same original grain boundary and different tensile directions, were prepared.
When they are deformed in tension to a strain of 0.3, the grain boundary is changed into different ones because of the operation of different slip systems. After annealing the recrystallization along/near the grain boundary occurs mainly due to ⟨111⟩ rotation mechanism in the bicrystal in which multiple slips of dislocations with large screw components on a certain slip system and those on other ones take place. In contrast, the strain induced grain boundary migration mechanism operates in the bicrystal whose grain boundary plane is parallel to edge dislocations entered into and piled-up toward the grain boundary.抄録全体を表示PDF形式でダウンロード (1575K) -
井口 征夫, 斉藤 文夫1994 年 58 巻 6 号 p. 605-612
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーComputer color mapping of the crystallographic orientation and lattice strain was performed on elongated and recrystallized grains at various thickness positions in the hot-rolled silicon steel sheet.
(1) At the 1/20 depth beneath the surface, in addition to the grains elongated in the rolling direction, “plate-like” elongated grains formed, with a rotation in the crystallographic plane of (110). These elongated grains comprised transverse deformation bands across a grain. Many recrystallized grains with random orientations formed preferentially at the grain boundary and in the deformation band, and were large, with an average grain size of 136 μm.
(2) At the 1/10 depth beneath the surface, the size of the elongated grains was heterogeneous. The elongated grains with Goss orientation were extremely large, and many small areas free from strain were present in the Goss-oriented grains.
(3) At the 3/20 depth beneath the surface, the grains elongated in the rolling direction and small-sized grains in the transverse direction formed with high frequency, and the elongated grains with Goss orientation became scarce. Recrystallized grains formed mainly at the grain boundary, but were small in size and relatively infrequent.
(4) The average size of the elongated grains at the 1/10 depth beneath the surface, where the elongated grains with Goss orientation formed, was the largest. These grains were smaller in the order of 3/20 and 1/20 depth.
(5) The formation frequency of recrystallized grains was smaller and less as the depth from the surface of the hot-rolled silicon steel sheet increased.抄録全体を表示PDF形式でダウンロード (973K) -
吉田 冬樹, 菅元 淳二, 中島 英治, 吉永 日出男1994 年 58 巻 6 号 p. 613-620
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーIn order to clarify the problems involved in the measurement of the threshold stress for high-temperature deformation in a dispersion-strengthened alloy, using an Al-1.5 vol%Be alloy in which the strengthening mechanism has been identified, the threshold stress was measured by four different techniques: tensile test, stress relaxation test, creep test and stress abruptly loading test. The measured values were compared with the Orowan stress and the void-hardening stress calculated from dispersion parameters.
The yield stress obtained from the tensile test at room temperature was higher than the Orowan stress: the proportional limit was about 1.3 times and the 0.2% proof stress was about 3 times. For the stress relaxation test, no clear zero-creep stress was observed at high temperatures and the approximately determined zero-creep stress strongly depended on temperature, decreasing as temperature rose. The threshold stress obtained from the creep test agreed approximately with the void-hardening stress or the slightly higher Orowan stress than the void-hardening stress. The threshold stress at high temperatures, 623 and 673 K, obtained from the stress abruptly loading test decreased from the Orowan stress to the void-hardening stress as the time elapsed under load. From these results, the problems in the measurement of threshold stress are discussed and the stress abruptly loading technique is recommended.抄録全体を表示PDF形式でダウンロード (657K) -
兪 成根, 佐藤 寛哲, 宮田 隆司, 大塚 昭夫1994 年 58 巻 6 号 p. 621-628
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーRolling contact fatigue tests were performed for two types silicon nitrides and a sialon using disk-type specimens. Both materials showed a fatigue behaviour similar to that typically found in metallic materials. From the fractographic and metallographic observations, it has been found that the crack initiation in the silicon nitrides subjected to rolling contact fatigue is to be induced by cyclic subsurface shear stress, as is known in steel bearings. On the mid-sections of the specimens, many subsurface cracks which lay parallel to the contact surface can be found at a depth where fluctuation of the Herzian shear stress was the maximum. The specimens subjected to the higher frequency rolling gave the shorter failure lives. Although the cyclic fatigue of ceramics under the pulsating uniaxial stress seems to be governed by environmentally assisted cracking, these facts suggest that the occurrence of cyclic dependent type of fatigue in ceramics is alternatively possible under the cyclic compressive stress state.抄録全体を表示PDF形式でダウンロード (1909K) -
阿部 千幹, 遠藤 富男, 酒井 貢1994 年 58 巻 6 号 p. 629-633
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーThe acoustic microscope is well known for non-destructive testing equipment. Recently, it finds wide application to quantitative measurement of physical properties of specimens using the V(z) curve that is a special characteristic of acoustic microscope. In this study, the new method is described for the non-destructive measurement of elastic constants and poisson’s ratio of non-ferrous metals in a very small area using an amplitude and phase acoustic microscope.
According to the elastic theory, elastic constants and poisson’s ratio are calculated from the longitudinal and shear wave velocities of a specimen. Both wave velocities can be measured by the complex V(z) curve that involves the amplitude and phase of the reflected signal from the specimen surface.
Seven pure non-ferrous metal specimens are selected for this experiment. After complex V(z) curves are measured at 400 and 600 MHz, their inverses Fourier transforms are calculated. Longitudinal and shear wave velocities are calculated from their critical angles obtained from the inverse Fourier transform. Elastic constants and poisson’s ratio are calculated by both velocities and the density. The values of measured elastic constants and poisson’s ratio for each specimen are in good agreement with the value in the data-book.
According to this results, it is shown that this method is applicable to the measurement of elastic constants and poisson’s ratio of non-ferrous metals in a small area.抄録全体を表示PDF形式でダウンロード (592K) -
黒田 健介, 堀部 泰隆, 藤澤 敏治, 山内 睦文1994 年 58 巻 6 号 p. 634-641
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーA new method (Tangent method) was developed for the determination of the effective valence of interstitial impurity elements that is one of the most important factors for the evaluation of the effectiveness of the solid state electrotransport (SSE). The Tangent method can overcome all the weak points in the traditional methods. For the confirmation of the Tangent method, the Fe-C and Fe-N systems were picked up as model systems, because the thermodynamic properties of these systems had been well established and there had been many reports on the SSE process of these systems. And experimental studies have been conducted under the following conditions: initial uniform carbon content=1300 mass ppm, nitrogen one=270 mass ppm, temperature=1273 K and current density=3∼5×106 Am−2.
The measurements shows good reproducibility and the following results were obtained:
(i) +3.7 and +3.1 were obtained as the effective valences of carbon and nitrogen, respectively.
(ii) These values are in good agreement with the ones measured by traditional methods.
(iii) The values of diffusion coefficient of carbon and nitrogen in γ-iron, which were obtained in the combination of the Tangent method and the traditional unsteady state method, agree well with the values in the literature.抄録全体を表示PDF形式でダウンロード (775K) -
田村 元紀, 田中 哲夫, 上田 学, 宮川 隆1994 年 58 巻 6 号 p. 642-647
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーTi-C-N films have been deposited at low temperatures (<250°C) by an reactive ion plating system activated by arc discharge and they were applied to tip saw. Heat transfer from evaporation source and ion impact to the substrate are main factors to affect temperature of substrate during ion plating. Both can be quantitatively controlled. Critical load (Lc) was poor when the deposition temperature was low. It is considered that the low Lc is due to high intrinsic residual stress in the film and poor adhesive force between the substrate and the film. Ion impact at early stage of deposition greatly improved the adhesion of the film. The ion impact could clean the surface, accelerate mobility of atoms and chemical reaction by increasing the temperature of the surface, and decrease the gap of physical properties between the substrate and the films by forming ion-impact-affected zone. Tool-life of tip saw was effectively improved by applying the low-temperature ion plating of Ti-C-N.抄録全体を表示PDF形式でダウンロード (866K) -
平井 伸治, 村上 英明, 片山 博, 上村 揚一朗, 三友 護1994 年 58 巻 6 号 p. 648-653
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーThe mixture of Al2O3 and AlN at a mole ratio of 7 to 3 was heated at various temperatures from 1973 to 2048 K in N2 atmosphere, to investigate the effects of crystal type of Al2O3 and of additives on the formation rate of aluminum oxynitride spinel (ALON). ALON was formed more rapidly for γAl2O3 than for αAl2O3. The addition of CaB4O7 to the mixture accelerated the formation of ALON, whereas the additives such as NaF, CaF2 and CaCl2 retarded its formation. It was found by the analysis of EPMA that the formation of ALON proceeded topochemically from the surface of Al2O3 particles to the inside. On the basis of the XPS analysis of AlN/Al2O3 interface, the diffusion of the O2− and N3− through the ALON layer was presumed to be a rate-determining step of the formation reaction. According to kinetic analysis of a solid-diffusion controlled equation, the apparent activation energy in the formation reaction using αAl2O3 was estimated to be 1143 kJ/mol for no additive and to be 1085 kJ/mol for the addition of 1 mass%CaB4O7. Whereas the apparent activation energy in the formation reaction using γAl2O3 was estimated to be 515 kJ/mol for the addition of 1 mass%CaB4O7.抄録全体を表示PDF形式でダウンロード (597K) -
佐藤 芳幸, 原 基, 品田 豊1994 年 58 巻 6 号 p. 654-659
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーDegradation of pure Fe was examined under oxygen including a small amount of HCl at high temperatures by measurement of mass change of specimens, observation and analysis of scales formed on the specimens. At the temperature of 873 K, mass gain of Fe in an 1%HCl atmosphere increased with time and was larger than that in pure O2. The mass gain at temperatures higher than 1073 K increased in an early stage, then turned negative after longer oxidation period. At these temperatures, the magnitude of mass loss after descaling measured in the 1%HCl atmosphere was rather smaller than that measured in the pure O2 atmosphere. When the decrease in mass gain was observed at 1173 K, the corrosion product was formed like a balloon shape. It was revealed by EPMA analysis that the mass loss at 1073 K was due to producing FeCl2 which has very high vapor pressure at the temperature. From these results, the high temperature oxidation mechanism of Fe in 1%HCl was discussed thermodynamically.抄録全体を表示PDF形式でダウンロード (1414K) -
魏 大維, 興戸 正純, 沖 猛雄1994 年 58 巻 6 号 p. 660-667
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーTitanium films were electrodeposited on 304 stainless steel by a pulse current method in an eutectic KCl-NaCl-LiCl mixture containing 2 mol%K2TiF6. The influence of electrodeposition conditions on the crystal orientation and morphology of the films was investigated by X-ray diffraction and scanning electron microscopy, respectively. With increasing temperature, Ti films electrodeposited by a pulse current show (110) preferred orientation. The morphology of Ti films showed well-crystallized grains, which became larger with increasing temperature. It was also found that the orientation and morphology of the Ti films changed with current density, time and pulse period. Corrosion resistance was estimated by anodic polarization method in 3%NaCl solution at 298 K. It was found that the films obtained above 873 K had a good corrosion resistance.抄録全体を表示PDF形式でダウンロード (2143K) -
香月 太, 深川 智機, 富田 俊郎, 前原 泰裕1994 年 58 巻 6 号 p. 668-674
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーScanning tunneling microscope (STM) has been applied to the investigation of surface morphology of silicon steel sheets. A polished specimen was annealed in a vacuum of 10−4 Pa at 1300°C for 10 min. The detailed observations reveal that fine facet structure is formed near (001) of the α-Fe grains, and that the terrace width and the step height of the facet are determined by the misorientation angle of the grains from the [001] orientation. These results and the observed minimum step height of 0.5 nm of the terrace suggest that the (001) surface of the silicon steel sheets can be covered with a thin iron oxide film with possible orientation relationship of α-Fe(001)\varparallelFeO(001) or α-Fe(001)\varparallelFe3O4(001) and α-Fe[100]\varparallelFeO[110] or α-Fe[100]\varparallelFe3O4[110]. The change of facet structures due to lowering annealing temperature are also discussed.抄録全体を表示PDF形式でダウンロード (2145K) -
新美 格, 奥宮 正洋, 篠宮 幸喜広, 森 大二1994 年 58 巻 6 号 p. 675-682
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーUnidirectional alignment and high volume of fibers efficiently increase the strength of fiber reinforced MMC. However, it is very difficult in an ordinary process to get a high orientation and volume of short fibers in MMC. This research was done to solve these problem of short fibers. The apparatus, which has superimposed magnetic fields generated by A. C. solenoid coil in the upper part, D. C. solenoid in the lower part and iron core in D. C. solenoid, makes the orientation of ferromagnetic short fibers in uniaxis. The fibrous preform made by this apparatus has less than 10 degrees of fiber orientation angle and 0.35 to 0.45 or higher of volume fraction of fibers. Inorganic fibers coated with ferromagnetic materials also could be aligned in uniaxis by the apparatus with a rather high magnetic flux density of D. C. solenoid. Fine crystallized α alumina fibers, 18 μm in diameter and 2 mm in length, which were coated with ferromagnetic nickel by electroless plating, were aligned uniaxaly in a casting mold. The molten magnesium alloy was sucked up and infiltrated into the mold under a low pressure of the vacuum pump. The Ni-B electroless plating process is effective in preventing the reaction between the nickel layer of fibers and molten magnesium. The thickness of the nickel plated layer needs to be 1 or 0.5 μm. With increasing thickness of the nickel layer, the nickel content in the magnesium matrix increases, and a larger volume of the brittle structure of Mg2Ni is formed. This decreases the strength of these composites. As an example of the strength of these composites, 1 μm nickel-coated alumina fiber reinforced magnesium alloy composites display a bending strength of 570 MPa in 0.4 volume fraction and 8 degree orientation angle. This is about twice the strength of the matrix.抄録全体を表示PDF形式でダウンロード (2342K) -
宇高 政道, 川嵜 一博, 山 隆雄, 梅本 実, 岡根 功1994 年 58 巻 6 号 p. 683-690
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーNi ultrafine-particles (UFP) were produced by direct current thermal plasma under various producing conditions in order to investigate a possibility of controlling the particle size of UFPs. In this study, influence of the gas pressure in reactive chamber in which the plasma flame spouted, and the feed rate of raw material powder on the particle size and size distribution of UFPs were investigated. The particle size distribution of UFPs were measured by analyzing the transmission electron microscope images.
The results obtained were as follows: (1) The size distribution of UFPs produced by thermal plasma conformed to log-normal distribution with 1.7-2.1 geometric standard deviation. (2) Specific surface area (SW) of UFPs decreased as the gas pressure in reactive chamber (PC) increased. There was a good linear relationship between log SW and log PC with a slope of −0.8. (3) Specific surface area (SW) of UFPs decreased as the feed rate of raw material powder (JP) increased. There was a linear relationship between log SW and log JP with a slope of about −0.2. (4) By considering the collision-coalescence mechanism, the dependence of specific surface area on the present producing conditions of UFPs was explained reasonably.抄録全体を表示PDF形式でダウンロード (1630K) -
宇都宮 裕, 左海 哲夫, 斎藤 好弘, 檜垣 研, 日方 威, 佐藤 謙一1994 年 58 巻 6 号 p. 691-696
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーSpread rolling methods are applied to a fabrication process of silver-sheathed superconductor (Bi, Pb)2Sr2Ca2Cu3Ox tapes. Two spread rolling methods are adopted. One method is the satellite-mill rolling which has been developed by the authors. The method is applied to the forming process of tapes. And the other method is a cross rolling, in which the tapes are rolled in the transverse directions. The cross rolling is applied as an intermediate rolling during the final sintering process, that is, the thin tape is pre-sintered, rolled and re-sintered.
The deformation characteristics of tapes, the microstructure and the texture of the oxides are investigated. And the critical current densities JC are measured at 77 K, 0 T. In order to make clear the effect of the spread rollings, these results are compared with those by the conventional longitudinal rolling method. Main results are as follows. (1) The high lateral spread rolling is realized by the satellite-mill rolling. In the tapes produced by the satellite-mill rolling, however, the silver sheath/oxide core interface is slightly inhomogeneous, and critical current density is little lower. (2) The critical current densities of the tapes deformed by the intermediate cross rolling is several times higher than those by the conventional rolling. (3) The sintered oxide grains are elongated in the direction of intermediate rolling. The texture is the c axis\varparallelN.D. fiber texture, and the c axes are dispersed in the direction of the intermediate rolling.抄録全体を表示PDF形式でダウンロード (1015K) -
松崎 祐司, 川村 昌志, 藤岡 順三, 岡崎 章三1994 年 58 巻 6 号 p. 697-706
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーFunctionally Gradient Material (FGM) promise to be used for heat insulation structures in advanced engine hot sections including gas turbines and supersonic/hypersonic propulsion systems. An application-capable damage mode modeling, however, is needed to realize the full potential of the thermal barrier performance and the durability benefits in practical service environments. The work reported herein describes the results of experimental and numerical considerations on the thermomechanical response of the FGM in transient thermal cycle environment. The maximum thermal shock resistant temperature of the stabilized zirconia/nickel chrome FGM was significantly dependent on the compositional distribution. Spallation was observed in very early periods after initiate heating when exposed in higher heat flux exceeding the heat resistance limit. Photomicrographical evidences indicated that the spallation is caused by the in-plain microcracks linking-up to the vertical cracks associated with the inelasticity of the zirconia ceramics. FEM analysis revealed both type of these cracks to be initiated as a result of the large in-plain compressive stress during the heat loaded cycle. Ceramics with adequate coefficient of thermal expansion are estimated to reduce the in-plain stress, improving the heat resistance limit of the FGM. Further thermal cycle test was conducted on stabilized zirconia-30 vol% cordierite/nickel-chrome FGM to illustrate the effect of the high temperature side thermal expansion on the in-plain stress reduction. The optimized FGM was 120 K higher in heat resistant surface temperature than the stabilized zirconia based FGM.抄録全体を表示PDF形式でダウンロード (2529K) -
真島 一彦, 小澤 義則, 勝山 茂, 永井 宏1994 年 58 巻 6 号 p. 707-714
発行日: 1994年
公開日: 2008/04/04
ジャーナル フリーThe preparation of Mn-Zn ferrites composed of fine grains has been carried out by hot pressing under various conditions. The results obtained are summarized as follows.
(1) α-Fe2O3 was more liable to form in the specimen prepared by hot pressing than in that prepared by the conventional sintering under ordinary pressure due to the remaining O2 in the specimen. Therefore, it was confirmed that the hot pressing process in vacuum was more suitable than in 1%O2 or N2.
(2) Mn-Zn ferrites whose grain size is about 2 μm was obtained by the process where the specimen was heated to 1248 K at the heating rate of 0.028 K/s, and isothermally held under 0 MPa for 1.8 ks and hot pressing under 40 MPa in the vacuum of 1.33×10−2 Pa for 1.8 ks at the same temperature of 1248 K, using coprecipitated Mn-Zn ferrites powders.
(3) Mn-Zn ferrites powder whose grain size is extremely fine of about 10∼20 nm was obtained by the MG process in Ar, and it was confirmed that using these powders, Mn-Zn ferrites specimen whose grain size is finer than 1 mm was prepared by the above mentioned hot pressing process.抄録全体を表示PDF形式でダウンロード (2414K)
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