日本金属学会誌
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
46 巻, 7 号
選択された号の論文の11件中1~11を表示しています
  • 猪子 富久治, 三原 陽一, 秋園 幸一
    1982 年 46 巻 7 号 p. 667-671
    発行日: 1982年
    公開日: 2008/04/04
    ジャーナル フリー
    Orientation controlled pure Al and Al-Si alloys bicrystals of certain shape were prepared by Bridgman’s method using a “soft mold” technique. The crystal boundary behavior during crystal growth from melt was examined. It is determined by following two the factors:
    (1) Extrinsic heat flow (heat flow in a specimen extrinsically depended on the temperature gradient in a furnace, the position of a specimen in a crucible, the shape and size of a specimen etc.)
    (2) Intrinsic heat flow (heat flow in a specimen intrinsically depended on the formation of cellular structure and precipitates etc.).
  • 猪子 富久治, 安宅 健, 木村 節, 秋園 幸一, 美馬 源次郎, 辛島 誠一
    1982 年 46 巻 7 号 p. 672-679
    発行日: 1982年
    公開日: 2008/04/04
    ジャーナル フリー
    In order to examine effects of the grain boundary on initiation of fatigue cracks, aluminum bicrystals were produced with Bridgman method. They were tested by a bending fatigue testing machine under the constant strain amplitude of 0.18%.
    It has been found that conditions necessary for the initiation of fatigue cracks along primary slip bands in the grain boundary affected-regions are as follows:
    (1) Dislocations parallel to the grain boundary planes are of nearly the screw type.
    (2) Cross slip on the primary slip systems can be promoted due to incompatibility of elastic and plastic strains at grain boudaries.
  • 田頭 孝介, Hutchinson W. B., Dillamore I. L.
    1982 年 46 巻 7 号 p. 679-686
    発行日: 1982年
    公開日: 2008/04/04
    ジャーナル フリー
    Additions of manganese and nitrogen have been investigated with respect to their effects on the development of recrystallization texture in very low carbon steels. Hot-rolled and decarburized steels with five different manganese contents (0.00 to 0.32 mass%) were individually adjusted to three levels of nitrogen (less than 2, 8 and 120 mass ppm) by atmosphere reactions and then cold-rolled 80% in reduction. These fifteen sheets were annealed up to 973 K with a very slow heating rate under appropriate atmospheres. Texture studies were carried out by X-ray diffraction method. Microstructures during recovery and recrystallization were also examined using the scanning electron microscope (back-sattered electron method) on the edge sections parallel to the rolling direction. Optimum textures for deep drawability were obtained with very low contents of manganese in solid solution (less than 0.04%) and intermediate levels of nitrogen (about 8 ppm). Steel chemistry apparently controls the final texture in both the cold rolling and annealing stage of processing. The cold rolling texture varies with manganese and nitrogen content. During recrystallization, nitrogen enhances the development of texture components with (111) parallel to the sheets.
  • 千葉 実, 安藤 勉
    1982 年 46 巻 7 号 p. 687-691
    発行日: 1982年
    公開日: 2008/04/04
    ジャーナル フリー
    Finely divided metal powders have been attracting a special attention for their physical and chemical characteristics. These metal powders frequently contain large amounts of gases through oxidation and surface adsorption due to their reactivity and very large specific areas. Many difficulties will be supposed to be in the analysis of oxygen in such metal powders by the usual methods of gas analysis in metals; a hard sample handling due to their bulkiness and very low apparent specific gravity; difficulties of replacement of dead volume by an inert gas or degassing when a sample is stuffed in a metal capsule or wrapped in a metal foil for easier sample handling in the usual methods; and tendency of scattering of samples in the instrument when such a powder sample of low apparent specific density and high gas content was thrown into the high temperature metal bath and by the following hard chemical reaction.
    The 14 MeV neutron activation analysis is considered to be effective to analyze such samples as fine powders, due to the unnecessity of the chemical reaction at the high temperature which is different from the usual methods. The analysis by the above method for iron powders prepared by a forced vaporization method with a plasma jet has been studied. The amount of a sample, 100 mg, is sufficient for the analysis, and there is no any obstructive radioactive nuclide simultaneously produced from the matrix iron in the measurement of 16N produced by the 16O (n, p) reaction with the 14 MeV neutron irradiation if the measured γ-ray energy range was limited to lie between 4.5 and 8.0 MeV.
    A calibration curve prepared from the standard series of oxygen-graphite can be used, and it is favorable because of the unnecessity of consideration of residual radioactive nuclides when repeated irradiation of samples is required.
    The analysis resulted in 2.47-12.6 mass% oxygen for three kinds of the samples, suggesting the importance of the control of residual gases in the instrument, that of the purification of the plasma gas, and that of prevention of oxidation of the products during storage.
    When an amount of oxygen corresponding to its statistical deviation is supposed to be a lower limit of detection, it becomes ca. 38 μg of oxygen or 0.038 mass% in a fine iron powder of 100 mg.
    A total duration of ca. 62 s is required for the analysis of one sample, and the external standard method is adopted to improve the accuracy and the reproducibility of this method.
  • 斉藤 守正, 須藤 恵美子
    1982 年 46 巻 7 号 p. 691-695
    発行日: 1982年
    公開日: 2008/04/04
    ジャーナル フリー
    The determination of sulfur in ferroalloy, iron ore and pig iron by the isotope dilution method using 34S enriched sulfur, combined with spark source mass spectrometry, was studied. This method is based on a conventional gravimetric method. Samples are dissolved in nitric acid and hydrochloric acid containing potassium chlorate and the spike solution which is prepared by dissolving elemental 34S in nitric acid, and potassium chlorate is added to the solution. In ferrosilicon and high carbon ferrochrome samples, those are fused with sodium carbonate or sodium carbonate and sodium peroxide. The resulting solution is evaporated to drynass. The salts are dissolved in hydrochloric acid, and metallic zinc is added to reduce ferric ions to ferrous ions. Barium chloride is added to the solution to precipitate sulfur as barium sulfate, and then the precipitate is filtered and ignited. The ignited residue is mixed with graphite powder and pressed into electrodes.
    The method was applied to the determination of sulfur in the JSS, NBS and BCS standard samples, and the results with satisfactory precision and accuracy were obtained for the analyzed samples except for ferrosilicon samples. The poor precision for ferrosilicon sample seems to be due to the blank of sulfur from reagents (Na2O2, etc.) used.
  • 井口 義章
    1982 年 46 巻 7 号 p. 696-703
    発行日: 1982年
    公開日: 2008/04/04
    ジャーナル フリー
    Effects of CaO and MgO as soluble additives in nickel oxide on the reduction of nickel oxide pellet were investigated. The foreign oxides were revealed to give almost the same effects as on the reduction of wustite. The following results were obtained.
    (1) CaO causes the reduction rate of nickel oxide to increase with increasing amount of CaO up to the amount in which the reduction rate is maximum, and over this amount the accerelating effect becomes weak gradually.
    (2) MgO retards the reduction of nickel oxide pellet as the amount increases.
    (3) The temperature dependency of the reduction rate of nickel oxide pellet containing CaO was hardly observed, but that of nickel oxide pellet containing MgO was very significantly compared with that of pure nickel oxide, and the reduction rate in the later period of nickel oxide pellets containing 2.4 mol%MgO was minimum at 1073 K, while that of pure nickel oxide pellets was minimum at 1173 K.
    (4) The reduction rates of nickel oxide pellet containing CaO at almost all the reduction temperatures employed in this work and those of pure nickel oxide pellet at 873 and 973 K can be represented by the mixed control equation based on an unreacted core model. On the contrary, the reduction rate of nickel oxide pellet containing MgO can be represented by the oxygen diffusion limiting rate equation through the metallic nickel shell formed on individual nickel oxide particles.
  • 杉本 克久, 原 信義, 一色 実, 江島 辰彦, 井垣 謙三
    1982 年 46 巻 7 号 p. 703-712
    発行日: 1982年
    公開日: 2008/04/04
    ジャーナル フリー
    Corrosion and electrochemical polarization properties of high purity Fe-Cr alloys (3-30 mass%Cr), which were prepared by an Ar plasma melting method using high purity Fe produced by a new method combining anion exchange and zone-refining processes and high purity Cr produced by an iodide process, have been measured in acid and chloride media, comparing with those of vacuum-induction-melted alloys made from electrolytic Fe and Cr and of commercially available ferritic stainless steels.
    In deaerated 10 mass%H2SO4 and 1 kmol·m−3 HCl, high purity alloys showed remarkably low corrosion rates: For example, in case of 15 mass%Cr alloys in 1 kmol·m−3 HCl, the corrosion rate of high purity alloy was only ca. 0.7% of that of vacuum-induction-melted alloy and ca. 5% of that of commercial steel. From cathodic polarization studies, the increased corrosion resistance of high purity alloys can be attributed to increased hydrogen overvoltages of the alloys.
    High purity alloys also exhibited extremely high corrosion resistance against pitting in chloride solutions: In case of 15 mass%Cr alloys in 5 mass%FeCl3+0.05 kmol·m−3 HCl, the corrosion rate of high purity alloy was only ca. 3% of that of commercial steel. Pitting potentials in 3 mass%NaCl, overvoltages of the reduction reaction Fe3++e→Fe2+ on passivated alloys, and the activation time of passivity in H2SO4 were found to increase with an increase in the purity of alloy. From these facts, it was presumed that compact passive films with low defect density were formed on high purity alloys and these films inhibited both the initiation and growth of pitting on the alloys.
  • 重野 芳人, 徳田 昌則, 大谷 正康
    1982 年 46 巻 7 号 p. 713-720
    発行日: 1982年
    公開日: 2008/04/04
    ジャーナル フリー
    The influence of sulfur or phosphorus on the rate of carbon dissolution from rotating graphite cylinders into the liquid iron alloys was studied in the temperature range of 1573-1773 K. Electrode-grade graphites (graphitizing and non-graphitizing carbon) were used. The results are summarized as follows:
    (1) Non-dimensional correlation between mass transfer of carbon in the Fe-C melt and the rotational speed was obtained, which was expressed as
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    \ oindentWhen sulfur or phosphorus was added, the results deviated from this correlation, which was interpreted in terms of mixed control of mass transfer and interfacial kinetics.
    (2) Phosphorus decreased the overall mass transfer coefficient k, which was presumed to be due to the effect of phosphorus adsorption through its influence on the interfacial kinetics. The dependence of k on the structure of graphite was found to be negligible.
    (3) Sulfur decreased k more than phosphorus, which suggested the more intensive surface activeness of sulfur. Particularly in the case of non-graphitizing carbon, k extremely diminished. This result would be attributable to the greater degree of adsorption of sulfur on non-graphitizing carbon than the graphitizing carbon.
  • 小野寺 龍太, 石橋 利之, 古賀 守, 清水 峯男
    1982 年 46 巻 7 号 p. 721-725
    発行日: 1982年
    公開日: 2008/04/04
    ジャーナル フリー
    Effects of composition and temperature on the occurrence of the Portevin-LeChatelier effect were investigated in the literature and the experiments in some alloys. These investigations show that the alloy systems are divided into two groups according to the minimum solute concentration below which the P-L effect does not occur. The first group, including Al-Mg, Al-Cu, Al-Ag, Cu-Sn and so on, consists of the alloy systems in which the P-L effects occurs at the solute content less than 1 atomic percent. A common feature of these systems is that they have small solubility of solute (the latter elements such as Mg in the Al-Mg system). On the other hand, in the systems such as Cu-Al, Cu-Zn and Ni-Cr classified in the second, the P-L effect does not occur at the solute content less than 5 atomic percent and the solute solubility is large. These results suggest that the P-L effect is related to the solubility limit or precipitation. In the current theory relating the P-L effect to the interaction of dislocations with solute atoms, the cause of interaction energy was mainly attributed to the size effect. But it is difficult for the theory to explain that although the P-L effect occurs at 0.5 at%Ag in the Al-Ag system (the atomic radii of the components are nearly equal), the P-L effect does not occur at 9 at%Al in the Cu-Al system (the atomic radius of Al (solute) atom is about 7% larger than that of Cu). We propose a new theory for the P-L effect that the precipitates or the short range ordered regions are formed in materials by the action of vacancies created by plastic deformation and interact with the dislocations.
  • 松浦 圭助, 松田 則男, 渡辺 勝也
    1982 年 46 巻 7 号 p. 726-734
    発行日: 1982年
    公開日: 2008/04/04
    ジャーナル フリー
    The kinetics of internal oxidation of a Ni-0.26%Ti alloy has been investigated in the temperature range from 1273 to 1573 K, and the morphologies and structures of the oxide particles formed have been studied by electron microscopy of extraction replicas.
    The kinetics of internal oxidation was well described by Wagner’s equation, that is, the penetration rate of the internal oxidation front is determined by the diffusion of the dissolved oxygen. The oxide particle size increased with distance from the specimen surface, but small particles were observed near the oxidation front. The shape of oxide particles was various: needle-like, plate-like and massive. Four kinds of oxides were recognized: NiTiO3, TiO2 (rutile), TiO2 (brookite) and TiO (NaCl type). NiTiO3 was mostly observed near the specimen surface. Rutile was generally observed throughout the internal oxidation zone and brookite only in a few cases. TiO was recognized among the small particles present near the oxidation front. Twins with {101} twinning plane and planar defects were often seen in some rutile particles. Especially, a rutile particle, which was near the oxidation front, showed a defects structure of many twins and planar defects similar to those seen in a slightly reduced rutile, TiO2−δ.
  • 木村 宏, 木村 晃彦, 松井 秀樹
    1982 年 46 巻 7 号 p. 735-736
    発行日: 1982年
    公開日: 2008/04/04
    ジャーナル フリー
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