巻号一覧
61 巻, 7 号
選択された号の論文の16件中1～16を表示しています
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関根 和喜1997 年 61 巻 7 号 p. 561-566
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーA concept of fuzzy constraints for grain-interactions modelling in the large deformation polycrystal plasticity is presented. In accordance with this concept, the formulation for a method in the Taylor type framework of polycrystal plasticity has been done as a fuzzy mathematical programming problem (we call the fuzzy-Taylor problem), by introducing the idea of ill-defined or ambiguous constraints of deformation imposed on each grain in polycrystalline aggregate. This fuzzy-Taylor problem can be described as a multiobjective mathmatical-programming containing fuzzy numbers which are charactirized through a triangular type of membership function. A solution method of this problem is provided for calculating the rolling texture of bcc metals deformed by ⟨111⟩ pencil glide. The predicted rolling texture of bcc metals based on the fuzzy model was distinctly different from ones by the FC and RC models, and it exhibited the presence of the so-called γ-fiber texture, in which the {111} planes are parallel to the rolling plane.抄録全体を表示PDF形式でダウンロード (472K) -
麻生 節夫, 蜂須賀 盛希, 後藤 正治1997 年 61 巻 7 号 p. 567-573
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーIn order to clarify the phase transformation of Fe-15 mass%Cr-C-B alloys, we prepared nine kinds of the alloys with different carbon and boron contents. The phase transformation behavior was examined with thermal expansion test, hardness test and SEM observation. The results obtained are as follows.
(1) The transformation behavior of the matrix phase depends on carbon and chromium content: that is, in the as-cast condition, the alloy containing more than 2 mass% boron and less than 1 mass% carbon transforms to bainite, while the alloy containing less than 1 mass%B and more than 2 mass%C transforms to pearlite, however, the alloy transforms to martensite in the as-quenched condition.
(2) On air cooling, the matrix transforms to pearlite, bainite or martensite with the change in chromium content from less than 6 mass% to more than 8 mass%. The Ms temperature decreases with increasing of carbon content in the matrix.
(3) The alloys containing low carbon and high boron possess a very high hardness of about Rockwell C60 even in the as-cast condition. It is possible that the alloys may be used without any heat-treatment, like a Ni-hard cast iron.抄録全体を表示PDF形式でダウンロード (1736K) -
尾中 晋, 廣瀬 達朗, 加藤 博之, 橋本 敏1997 年 61 巻 7 号 p. 574-579
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーA geometrical analysis is made for the determination of aspect ratios and orientation of an ellipsoidal particle by stereo observation. The stereo observation is made by comparing changes in projected images caused by tilting of the particle. The aspect ratios, principal axes and orientation of the ellipsoidal particle are obtained from its projected images if we observe the particle from three different directions. As an example of applications of the present method of analysis, the shape change of a liquid B2O3 particle induced by plastic deformation of a Cu matrix is shown.抄録全体を表示PDF形式でダウンロード (692K) -
小野 義彦, 中津 英司, 高木 節雄1997 年 61 巻 7 号 p. 580-585
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーIn Fe-22 mass%Mn alloys containing niobium (Nb) and carbon (C), the effects of austenite (γ) grain size and NbC particles on γ→ epsilon (ε) martensitic transformation have been investigated by means of optical microscopy, transmission electron microscopy and X-ray diffractometry. Nb and C were added to give the volume fractions of 0.5 and 1% as NbC particles. Austenite grain size was altered from 3 to 30 μm through the recrystallization of deformed γ. Martensitic transformation from γ to ε was significantly suppressed by the finely dispersed NbC particles. The amount of ε martensite depends on the mean free path (m.f.p.) of NbC particles, particularly when it was reduced to 0.2 μm or less, the γ→ε martensitic transformation was completely suppressed. Such a marked suppressive effect by a small quantity of precipitates is caused by the elastic stress field around NbC particles, which has been formed to keep the coherency with the γ matrix. It was suggested that all the γ matrix is coverd with the elastic stress field when the m.f.p. of NbC particles is reduced to 0.2 μm or less. The suppression of γ→ε martensitic transformation by NbC particles is explained in termes of interaction of partial dislocations with NbC particles and their elastic stress field: The movement of partial dislocations is indispensable for the nucleation and growth of the ε martensite, but it is stopped by the finely dispersed NbC particles themselves or their elastic stress field. It is concluded that the complete suppression of the γ→ε martensitic transformation in the region of less than 0.2 μm in m.f.p. is not due to grain refining of austenite, but due to the suppression of nucleation of the ε martensite by such an interaction between partial dislocations and NbC particles.抄録全体を表示PDF形式でダウンロード (1078K) -
張 弓, 西方 篤, 水流 徹1997 年 61 巻 7 号 p. 586-594
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーThe hot corrosion resistance of twelve Ni-base alloys was evaluated at 873 K by three different laboratory tests; immersion test, salt coating test and embedding test. In these tests, three different corrosion ashes were employed, a sulfate (Na2SO4-K2SO4-ZnSO4), a chloride (NaCl-KCl-LiCl-CaCl2) and a chloride/sulfate mixture (NaCl-KCl-Na2SO4-K2SO4-ZnSO4). The correlations between the ranking of the corrosion resistance of the alloys in the immersion test, coating test and embedding test were investigated using spearman’s correlation coefficient. The results of the three tests were highly correlated in the sulfate and chloride/sulfate environments, whereas they were relatively poorly correlated in the chloride environment. It was found from the anodic polarization measurement and X-ray difraction analysis of the corrosion products that the relatively poor correlation is attributed to the differences in the rate-determining steps of the corrosion. In the sulfate environment, there was small difference of the corrosion mass loss among the three tests, but in both the chloride and chloride/sulfate environments, the mass losses in the coating test and embedding test were much larger than that in the immersion test. The corrosion mechnisms under the respective corrosion test conditions were discussed.抄録全体を表示PDF形式でダウンロード (1149K) -
竹内 宏充, 恒川 好樹, 奥宮 正洋, 遠山 正之1997 年 61 巻 7 号 p. 595-601
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーThis paper presents a novel pretreating method for electroplating on aluminum alloy substrates, in which an electrolyte jet containing coarse and fine SiC particles is ejected to the substrate surface prior to jet electroplating. The electrolyte jet with high velocity roughens the substrate surface due to the collision of coarse particles. The pretreatment with an inclined electrolyte jet is more effective to create a hooked substrate surface which is expected to reveal an anchoring effect in adhesion. Jet electroplated Ni-P deposits with a compositional gradient of fine SiC particles on the substrate, which has been pretreated by the inclined jet, show superior adhesive strength comparing with those done by a conventional double zincate pretreating method. The surfaces of electrodeposited nickel are plastically deformed by vigorous particle collision during the jet electroplating, so that there exists a compressive residual stress which increases with jet velocity increased. The vigorous particle collision also gives rise to harder deposits due to work hardening.抄録全体を表示PDF形式でダウンロード (2153K) -
宇田 哲也, 岡部 徹, 葛西 栄輝, 早稲田 嘉夫1997 年 61 巻 7 号 p. 602-609
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーAn attempt has been made to obtain direct evidence of electrochemical redox reaction, i.e. electronically mediated reaction (EMR) during TiCl4 reduction by magnesium, and it includes a clear understanding of the mechanism of titanium deposition in the Kroll process. Feed material of TiCl4 and reductant magnesium were charged into different locations in molten MgCl2 at 1073 K. Large current, more than 5 A, between these feed and reductant locations has been clearly detected when shortening these electronically isolated sites, and metallic titanium deposits were observed in the TiCl4 feed site. Reproducibility of these experiments was well-confirmed. Thus, magnesiothermic reduction of TiCl4 appears to occur by EMR without direct physical contact between feed and reductant. The usefulness of the concept of EMR was demonstrated by explaining mechanism of titanium deposition in the sponge form on the reactor wall and reaction pathways including the crawling behavior of magnesium on the metallic wall surface in the Kroll process. The present results suggest the concept of EMR plays an important roll in metallothermic reduction of TiCl4 due to electron transfer through an electronically conductive medium, e.g. reaction wall and titanium deposit and due to ion transfer through MgCl2 as an ionic conductive medium.抄録全体を表示PDF形式でダウンロード (1195K) -
岡部 徹, 宇田 哲也, 葛西 栄輝, 早稲田 嘉夫1997 年 61 巻 7 号 p. 610-618
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーThe mechanism of titanium deposition has been investigated in the study on the electronically mediated reaction (EMR) during metallothermic reduction. The importance of EMR as well as its usefulness on the mechanism of titanium deposition was recognized by utilizing isothermal chemical potential diagrams for Ti-Mg-Cl and Ti-Na-Cl at 1073 K. Phase equilibria and reaction pathways in the Kroll or Hunter process were also considered.
In the Kroll process, a long-range electronically mediated reaction (LR-EMR) in which the titanium deposit and the reaction container act as an electron conductor was found to be dominant, and this leads to the formation of sponge titanium. Both the electron and ion transfers in NaCl solutions are quite likely to occur in the course of sodiothermic reduction of TiCl4. Thus, the formation of titanium powder in the Hunter process may be attributed to the short-range electronically mediated reaction (SR-EMR).抄録全体を表示PDF形式でダウンロード (1084K) -
藤田 康世, Pagador Romeo U., 日野 光久, 阿座上 竹四1997 年 61 巻 7 号 p. 619-624
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーFor thermochemical analysis of the phase equilibrium between the nickel alloy and slag phases in relation to the nickel smelting process, the mass spectrometer combined with a double Knudsen cell was adopted to measure the activities of the elements in the molten Cu-Ni and Cu-Ni-Fe alloys and the activity of sulfur below 5 at%S in the ternary alloys at 1623 K. A major feature of this set-up is that the activity values of the components can be determined at every experimental point without applying the Belton-Fruehan equation which requires the ion intensity measurement over the whole alloy composition region. In the present study, the following results were obtained.
(1) The activities of copper and nickel in the molten Cu-Ni alloys show a slightly positive deviation from the Raoult’s law and the activity behavior is consistent with a reference in the composition region higher than 50 at%Cu.
(2) The copper activity in the composition region over 30 at%Cu of the Cu-Ni-Fe ternary system shows a positive deviation from the ideal behavior and the deviation increases with increasing iron content in the Cu-Ni alloy.
(3) The activity coefficients of sulfur at infinite dilute solution in the Cu-Ni-Fe ternary alloys are found to be between 3 to 4×10−2 in the composition region over 30 at%Cu. This tendency agrees with the sulfur behavior expected from the Cu-Ni-S and Fe-Ni-S systems.抄録全体を表示PDF形式でダウンロード (551K) -
岡田 亮二1997 年 61 巻 7 号 p. 625-628
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーThe effect of heat treatment on the characteristics of WC-27 mass%NiCr sprayed coatings on 13%Cr steel made by the High Velocity Oxygen-Fuel Flame Spraying (HVOF) was studied. Specimens were heated to 673 K and held at 5, 10, 20 and 30 h in air. Corrosion resistance was measured by a salt-spray test (CASS test) and strength was measured by a three-point bend test. The results obtained were as follows: (1) Corrosion resistance increased with heating time. This increase is dependent on the surface void ratio of the sprayed coatings which decreases as the temperature increases. (2) The three-point bending strength decreases at 5 h heating, and increases again with continued heating. The initial decrease at 5 h heating was due to release of compressive stress in the coatings, and the increase afterwards was due to the surface void ratio decreasing.抄録全体を表示PDF形式でダウンロード (581K) -
谷 和美, 竹内 純一, 小林 圭史, 碓井 建夫1997 年 61 巻 7 号 p. 629-635
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーThe representative factors that have been studied in the development of thermal spraying processes are the heating and the acceleration techniques of spray particles. As the simultaneous promotion of heating and acceleration of particles in thermal spraying, which is performed in an extremely short time, is contrary to each other, there is a limit for the attainment of both. In this study, from the point of acceleration of spraying particles, the velocity of WC cermet spraying particles in two types of high velocity oxygen-fuel flame spraying process was measured by using a CCD video camera system with a high-speed electrical shutter. The determined velocities of the WC-12 mass%Co powder in the size range of 45 to 5 μm and the WC-20 mass%Cr3C2-7 mass%Ni powder in the size range of 45 to 10 μm were 300∼600 m·s−1 and 300∼500 m·s−1, respectively. It is apparent that the particle velocity in the high velocity oxygen-fuel flame spraying process was much higher than that in the plasma spraying process. These results were consistent with those reported previously. The driving force for higher acceleration in the high velocity oxygen-fuel flame spraying process was discussed. As the result of the estimation of the drag force for particles in spraying fluid, it was derived that the main factors which dominated the higher acceleration were large in density and high in velocity of the combustion gas mixture as compared with Ar-He plasma jet.抄録全体を表示PDF形式でダウンロード (689K) -
馮 吉才, 奈賀 正明, Schuster Julius C.1997 年 61 巻 7 号 p. 636-642
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーSolid-state bonding of pressureless-sintered SiC has been carried out using 20 μm Cr foil at temperatures from 1373 to 1773 K for a constant 1.8 ks in vacuum. The formation of reaction phase and microstructure at the interfaces between SiC and Cr were investigated by X-ray diffraction and electron probe microanalysis. At the bonding temperature of 1373 K, the cubic Cr23C6 phase next to Cr and the hexagonal Cr7C3 phase next to SiC were formed. Further, the cubic Cr3SiCx phase appeared on the SiC side at bonding temperature 1473 K. Upon the rise of joint temperature to 1573 K, the hexagonal Cr5Si3Cx phase is formed at the interface of SiC/Cr3SiCx. At a highest bonding temperature of 1773 K, Cr, Cr23C6, Cr7C3 and Cr3SiCx were consumed and resulted in the formation of the layered structures such as SiC/Cr5Si3Cx/Cr7C3/Cr5Si3Cx/SiC.
The strength of SiC joint with Cr7C3 adjacent to SiC showed the maximum strength, and degrades with the formation of the brittle phases of Cr3SiCx and Cr5Si3Cx.抄録全体を表示PDF形式でダウンロード (925K) -
小野 芳樹, 一柳 隆治, 大中 逸雄, 山内 勇1997 年 61 巻 7 号 p. 643-649
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーAlmost zero magnetostrictive Fe-6.5 mass%Si alloy fibers less than about 90 μm in diameter, having a large Barkhausen effect in magnetic properties were obtained by using the laboratory scale, the In-Rotating-Liquid-Spinning Process (INROLISP). The spinning conditions, jet stability, morphology of dendritic growth and magnetic properties were discussed for the fiber about 70 μm in diameter from the manufacturing viewpoint. In the case of spinning speeds of less than about 10 m/s, the jet bounced on the surface of rotating liquid, such as water, water with chemicals lowering surface tension, and some oils. Over 10 m/s, the jet subsequently penetrated under the liquid surface after an interval of around 100 ms from ejecting start. The centrifugal force effect was considered in this phenomenon. When the jet bounced, in some part of the fiber structure, primary dendrite arms growing uniformly along the fiber direction were observed. In another part, however, the direction of the primary arm changing gradually far from the fiber axis and the secondary arm becoming the primary grown to the fiber axis was observed without clear grain boundary. It is considered that the curvature of the bouncing jet at the ejection point obstructs the primary arms growing in a straight line. When jet penetrated, the “bamboo structure” was observed in the fiber structure. The penetrating jet formed the cavity of the coolant at its downstream from the jet. It means that the penetrating jet at first goes through the non-contacting area to the coolant at the cavity side and the contacting area to the coolant at the opposite side. Therefore, the primary arms tend to grow from the contact to the cavity sides. By the zone-annealing process, it was difficult to make any fiber a fairly long single crystal. In order to control the continuous growth of the primary arms toward the fiber direction, it was suggested that the process which is able to cool the jet uniformly around its circumference and make the primary arms grown in a straight jet is needed. The necessary conditions to produce a fiber having the large Barkhausen effect in this alloy, were the nearly unidimensional shape and a [100] crystal direction of arpha-phase parallel to the long axis. Furthermore, to obtain an ideal rectangular hysteresis loop, the cross-sectional round shape, the absence of residual stress and precipitation was suggested.抄録全体を表示PDF形式でダウンロード (848K) -
小野 芳樹, 一柳 隆治, 大中 逸雄, 山内 勇1997 年 61 巻 7 号 p. 650-655
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーA new process where a melt jet is quenched in gas followed by winding in a rotating liquid, which is a modified process of the In-Rotating-Water-Spinning Process (INROWASP), has been developed in order to make a continuous Fe-6.5 mass%Si alloy fiber with primary dendrite arms parallel to the fiber axis, having nearly zero magnetostriction. The molten alloy is ejected down from a nozzle through the He gas zone located just under the nozzle, followed by the O2 gas zone. Herium gas protects orifice plugging with metal oxides. Oxygen in the next zone forms the metal oxide sheath on the jet surface to refrain the jet from breaking up. The straight jet covered with oxide film was continuously solidified and caused recalescence. After the recalescence the fiber was wound in the rotating liquid. In the atmosphere without the oxidization zone, such as only He or NH3 vapor, the jet was more rapidly cooled but produced only particles. In the case of CO2 in the oxidization zone, the jet became particles and short fibers. The capillary breakup length of a jet (LBU) can be calculated by LBU=K·V· (ρ·d3⁄γ)1⁄2, where V; mean velocity of a jet, ρ; density of molten alloy, d; diameter of nozzle, γ; surface tension of molten alloy. In this work, the coefficient K was estimated to be 10∼20 from the experimental results for the zone length of He and the velocity of the jet. The spinning gap between the nozzle exit and the rotating liquid surface was set at 0.2∼1.0 m which was longer than the length between the nozzle exit and the start of recalescence. Fibers about less than 100 μm in diameter, longer than 10 m in length, having the large Barkhausen effect in the magnetic properties were obtained.抄録全体を表示PDF形式でダウンロード (1479K) -
岡崎 義光, 許 健司, Rao Sethumadhavan, 立石 哲也1997 年 61 巻 7 号 p. 656-661
発行日: 1997年
公開日: 2008/04/04
ジャーナル フリーThe total expenditure incurred in the import of materials for artificial bones and joints is increasing every year in Japan. Keeping this in view, anodic polarization of various metals like Ti, Al, V, Zr, Sn, Nb, Ta, Pd, Mo, Si, Co, Ni, Cr and Fe and cytocompatibility of these metallic powders by using L929 cell line were investigated. The corrosion resistance for Ti, Ta, Nb and Si in Eagle’s medium solution was excellent. In the case of Zr, Sn, Cr and Mo the passive films on the surface of these metals were formed, but tends to break as the potential increased. On the other hand the corrosion resistance was not very satisfactory for Al, V, Pd, Ni, Co and Fe. The results were similar in 1% lactic acid solution except that, the passive film formed on the surface of Zr and Al are stable as compared with that in Eagle’s medium. The relative growth ratios of L929 cells for Ti, Sn, Ta, Nb, Zr, and Cr powders extraction was equal to unity. The relative growth ratios for Al, V, Co, Ni, Pd, Fe, Si and Mo powders extraction decreased as the metallic concentration increased in the Eagle’s medium. Also, the effect of relative growth ratio of L929 cells for various metals was examined with the corrosion potential and the potential at 0.1 A·m−2 obtained by the anodic polarization curve. It was found that the relative growth ratio of L929 cells tends to be low for metals less than 0 V and high for metals more than 0 V at a current density of 0.1 A·m−2. Moreover, the relative growth ratio of L929 cells for Al(OH)3 powder extraction and AlCl3·6H2O dissolution from Al powder extraction was estimated in order to understand the chemical configuration of Al in Eagle’s medium solution. It was found that the relative growth ratio of L929 cells almost became equal to 0 for Al powder at a metallic concentration of 0.4 mass ppm. On the contrary, the relative growth ratio of L929 cells for AlCl3·6H2O dissolution was equal to unity up to a fairly high concentration of 50 mass ppm. Based on the results obtained, cytocompatibility of the various metals was compared with the Mandeleef’s periodic table.抄録全体を表示PDF形式でダウンロード (972K) -
渡辺 孝一1997 年 61 巻 7 号 p. 662
発行日: 1997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 (159K)
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