日本金属学会誌
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
48 巻 , 11 号
選択された号の論文の15件中1~15を表示しています
  • 高橋 徹, 堀内 良
    1984 年 48 巻 11 号 p. 1035-1040
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    A coupling of grain boundary migration and sliding was observed on the {1\bar211} coincidence boundary in a Zn bicrystal, viz. 0.52 rad ⟨10\bar10⟩ symmetric tilt boundary, under applied shear stress at high temperature. The ratio of the amount of grain boundary migration to that of sliding, which was measured to be ∼2, and the migration direction were in accordance with the DSC dislocation model’s prediction.
  • 李 絏, 入江 祥智, 山本 悟, 川野 豊
    1984 年 48 巻 11 号 p. 1041-1046
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    The effects of Mg and S on the spheroidization of graphite were investigated. The process of the graphitization was controlled in an annealing atmosphere under of various partial pressures of hydrogen diluted with argon. The results obtained are as follows:
    (1) The spheroidization of graphite by Mg was almost independent of the rate of graphitization.
    (2) The spheroidizing effect of S is, on the contrary, considerably affected by the rate of graphitization, which means that there exists an incubation time required for the spheroidization.
    (3) The incubation time is shortened as the annealing temperature increases in the temperature range between 1173 and 1253 K.
    The spheroidizing mechanisms of Mg and S may be as follows. Mg becomes gas bubbles in molten cast iron and is frozen in by casting. S causes micropores during annealing at temperatures higher than its boiling point. C atoms precipitate into these voids or pores to form spheroidal graphite.
  • 李 絏, 森 禎一郎, 山本 悟, 川野 豊
    1984 年 48 巻 11 号 p. 1047-1052
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    Deformation promotes graphitization and increases the numbers of graphite particles in cast iron. Deformation suppresses the spheroidization of graphite in Mg-treated cast iron. On the contrary, deformation promotes the spheroidization of graphite in S-treated cast iron if graphitization proceeds relatively slowly.
    These phenomena are explained in terms of the creation-annihilation behaviour of various defects and the interactions between additional elements and defects during annealing
  • 四竃 樹男, 藤 正和, 福富 勝夫, 岡田 雅年, 五明 由夫, 渋木 邦夫
    1984 年 48 巻 11 号 p. 1053-1060
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    Fully annealed molybdenum, which was coated with titanium carbide and/or titanium nitride by the chemical vapour deposition, was tensile tested at 300 and 1070 K. The results were compared with those obtained on the uncoated ones.
    The coated molybdenum was found to have a higher yield strength with smaller rupture elongation and reduction in area than the uncoated one. The coating also changed the rupture mode of molybdenum from the intergranular to the transgranular.
    A sharp yied drop and small stress drops during deformation were observed on the molybdenum coated with the titanium carbide at 300 K. These stress drops were accompanied with acoustic emmisions. Metallographic observation gave no evidence of the contamination of molybdenum by the carbon or nitrogen.
    The obtained results strongly suggested that the molybdenum was not contaminated during the chemical vapour deposition which used corrosive gases at elevated temperatures.
    The change in the tensile properties of molybdenum due to the coating is thought to be attributed to the strong constraint effect of the adhesive films on molybdenum.
  • 中佐 啓治郎, 陳 効列, 武井 英雄
    1984 年 48 巻 11 号 p. 1060-1067
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    The effects of tempering temperature, prior austenite grain size, stress intensity factor and testing temperature on the micro-branching frequency λ were investigated on a Ni-Cr-Mo high strength steel (SNCM 439) quenched and tempered, λ being defined as the ratio of the number of intergranular crack branching to the number of grains per unit length.
    λ takes a maximum value in the tempering temperature range of temper brittleness, and increases with increase in the prior austenite grain size. λ increases also with increase in the stress intensity factor K up to 40 MPa·m1⁄2 and then decreases for the material tempered at 623 K, whereas for the material tempered at 473 K it is almost constant independent of K. λ increases also with increase in the testing temperature for the material tempered at 473 K, whereas it is almost constant independent of the testing temperature for the material tempered at 623 K.
    The experimental results can be interpreted by considering the change in the binding strength of two grain boundaries at the triple point due to the segregation of impurity atoms, the dislocation pile-up and the corresponding hydrogen concentration on grain boundaries.
  • 古川 稔, 松井 昭彦, 美浦 康宏, 根本 実
    1984 年 48 巻 11 号 p. 1068-1074
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    Yield stress of aged Al-11.1 mol%Li alloy was measured at temperatures between 77 and 523 K, and the deformation-induced dislocation structure was examined by transmission electron microscopy. Strength and dislocation arrangements depend largely both on the aging conditions and on the testing temperature. The peak positions in strength vs aging time curves shift to the side of shorter aging time with increasing testing temperature. The mode of interaction between dislocations and δ′-precipitates also varies with the testing temperature. For the specimens aged nearly to the peak strength, the positive temperature dependence of yield stress is observed in the temperature range where dislocations move in pairs cutting the δ′-precipitates. In the over-aged specimens, dislocations by-pass the precipitates leaving dislocation loops around the precipitates at the beginning of plastic deformation. The shift of peak positions in the aging curves and the variation of the interaction modes between dislocations and precipitates with testing temperature are explained in terms of the positive temperature dependence of cutting stress and the negative temperature dependence of by-passing stress.
  • 新井 甲一, 有川 正, 嘉藤 雅記, 位崎 敏男
    1984 年 48 巻 11 号 p. 1075-1080
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    The selective leaching of lead dioxide from the battery slime in acidic ferrous chloride solutions is investigated from both a thermodynamic and a kinetic aspect based on the experimental results obtained on leaching rates, stoichiometry of the reaction and X-ray diffraction analysis of the leaching products.
    The experimental results are as follows:
    (1) The leaching rate of lead dioxide from the battery slime proceeds rapidly at an initial stage of leaching, and the rate is directly proportional to both the concentration of ferrous ions and the surface area of the battery slime sample. However, the dissolution of lead sulfate in battery slime is less than 12 percent under the same leaching conditions, and then the selective leaching of lead dioxide from the battery slime is possible.
    (2) The overall reaction for the selective leaching of battery slime in acidic ferrous chloride solutions is a simultaneous reaction of acid dicomposition and reduction of the slime.
    (3) The overall reaction for the selective leaching of battery slime is controlled by the mass transport of some species through the solution boundary layer between the solid phase and the bulk solution.
  • 安藤 繁, 岡本 恭和, 下尾 聰夫, 木村 弘
    1984 年 48 巻 11 号 p. 1080-1085
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    The carbon deposition behavior by pyrolysis reactions of CH4-H2 mixtures on iron at 1133 to 1323 K has been studied.
    Kinetic measurements and chemical analyses showed that the carbon deposition started when the carbon concentration in iron reached the solubility limit of graphite in austenite. Two types of carbon, filmy carbon and filamentous carbon, were observed on iron. The deposition of filmy carbon proceeded at an early stage, and particularly at temperatures above 1273 K filmy carbon spreaded on iron so fast that the iron surface was completely covered with it in a very short time. After some induction periods filamentous carbon deposited on the iron substrate which had been covered with filmy carbon, so that it brought the film to the local break.
    Mechanisms are suggested for the deposition of these two types of carbon.
  • 宮田 保教, 鈴木 俊夫, 宇野 純一
    1984 年 48 巻 11 号 p. 1086-1091
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    An Al-4.1 mass%Cu alloy was unidirectionally solidified under both the gravity force and the accelerational force with values of 3 G and 5 G. The dendrite tip radius of curvature, ρ, the primary arm spacing, λ1, the length of tips, λ0 and the tip concentration, Ctip, etc. were measured as functions of the growth rate, R.
    The tip radius of curvature and the primary arm spacing decreased with the increase of accelerational force. Under 5 G, the values of ρ and λ1, decreased by about 20% and 25%, respectively, from those under 1 G. Their dependences on the growth rate, however, were comparable with those under 1 G. The tip concentration was not affected by the operation of accelerational force, and gravity segregation was not confirmed.
  • 萩原 益夫, 海江田 義也, 河部 義邦
    1984 年 48 巻 11 号 p. 1092-1098
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    The effect of heat treatments on the microstructure and the resultant tensile properties were evaluated for alpha-beta HIP consolidated Rotating Electrode Process (REP) Ti-6Al-4V powder compacts. The cryogenic temperature tensile behaviour was also investigated. Metallographic and fractographic observations were made using light and scanning electron microscopy, and X-ray energy dispersive analysis.
    The tensile strength and ductility of Ti-6Al-4V alloy fabricated by this (REP+HIP) method were found to be equal to those of wrought materials both at room and cryogenic temperatures.
    The tensile properties varied significantly as the microstructure was altered by heat treatment. The best combinations of strength and ductility were obtained for the as-HIP fabricated and mill annealed materials. The solution treated plus aged material showed the highest strength and moderate ductility, whereas beta annealed material exhibited the lowest strength and ductility. Many inclusions having an average diameter of 10∼20 μm were observed on the fracture surfaces. These inclusions were rich in Al, Si, S and Fe. Various non-metallic and metallic impurities were also identified. Of all the tensile specimens in which inclusions were observed, only one specimen showed inclusion-related fracture initiation.
  • 洪 俊杓, 梅田 高照, 木村 康夫
    1984 年 48 巻 11 号 p. 1099-1105
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    The boundary element method was applied to simulate Stefan’s problem, and its results were compared with Neumanns’ solution. Temperature distributions and solidification thicknesses in solidification of iron, copper, and aluminum, calculated by the boundary element method, were in good agreement with the analytical solution. The proper time step in the boundary element method is closely related to geometrical data and thermal diffusivity, and it influences solution accuracy. It was found that the proper time step for transient heat conductions could be applied to simulate solidification problems involving phase change. The temperature recovery method was found to be a reasonable method to treat the latent heat of freezing during solidification in the boundary element method.
  • 柳沢 平, 矢野 哲夫, 佐藤 公士
    1984 年 48 巻 11 号 p. 1106-1112
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    Effect of thermal history on the residual stress of Al-Al3Ni eutectic composites has been investigated. At first, the relationship between the residual stress and the tensile and compressive deformation behavior is analyzed by a rule of mixture, to examine the method of determining the residual stress. It is shown that the usual method to determine the residual stress from the proportional limits of the composite is not adequate, because the Bauschinger effect in the matrix due to the plastic deformation during the previous thermal history can not be ignored. In this study, the residual stresses are schematically determined by the hysteresis loops of tensile and compressive stress-strain curves.
    The residual stress in the matrix at room temperature is in the tensile stress state. This residual stress gradually decreases and then changes into the compressive one at temperatures higher than about 400 K, when it is subsequently heated from room temperature. The absolute values of the compressive residual stresses coincide with the proportional limits at temperatures higher than about 500 K. The residual stress in the matrix at room temperature also coincides with the proportional limit and is influenced by the cooling rate. It was shown that the change in the residual stress at various temperatures was able to be explained by using the rule of mixture.
  • 船見 国男, 関口 行雄, 舟久保 煕康
    1984 年 48 巻 11 号 p. 1113-1119
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    Using pure titanium and nickele powders, a TiNi shape memory alloy was experimentally manufactured by the vacuum hot pressed powder metallurgy method. An influence of various hot pressed forming process on the homogeneity of alloy structure was investigated to fabricate practical device parts with the shape memory effect.
    The results are as follows.
    (1) The chemical diffusion of pure Ti and Ni mixed powder shows a thendency towards inferiority as compared with bulk materials. However, above 1273 K, the diffusion behavior of this powder, which has the liquid phase locally, was closer to that of bulk materials.
    (2) The homogeneity and density of TiNi alloy varied according to temperature and pressure as well as to the holding time. A density of 96-97% of the ideal value was obtained using a mixed powder of pure Ni and Ti processed by the vacuum hot pressed method at temperature 1323 K, pressure 35 MPa and holding time 3.6 ks.
    (3) The transformation temperature region (Ms-Af) shows slightly unsharpness as compared with that of molten material. But the result of mechanical and SME test confirmed that these alloys have extremely effective shape memory characteristics, that is, the recovery stress was 75-80% of that of molten material. Finally, as a practical example, we tried the fabrication of a spring washer and a pipe joint tube.
  • 浅沼 博, 大蔵 明光
    1984 年 48 巻 11 号 p. 1119-1126
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    As lightening of movable structure has recently been important from the standpoint of saving natural resources and energy, CF/Al composite has attracted attention. In the present study, applicability of the combination process of plasma spray and roll diffusion bonding as a low cost fabrication process to CF/Al composite has been investigated.
    The results are as follows:
    (1) Though the tesile strength of CF/Al composite remarkably varied depending on the fabrication conditions of roll diffusion bonding, it attained to 312 MPa (Vf: 0.12) by selecting favorable conditions.
    (2) Both of carbon fibers and aluminum powder for plasma spraying were not properly supplied to this process. With regard to fibers, as it was almost impossible to spread fibers uniformly, tows and crossings of fibers remained in the composite. Tows of fibers did not fully work as reinforcement. Crossings of fibers generally caused fiber breakages. With regard to powder, as the particle size was far larger than the fiber diameter, any uniform preformed sheet was unable to be obtained. Non-uniform distribution of matrix mainly caused fiber breakages. Smaller powder caused a more uniform preformed sheet and a higher tensile strength composite.
    According to these results, the possibility of CF/Al composite fabrication by this process is suggested, and it becomes more convincible by improving the state of fibers and powder.
  • 和田 仁, 伊藤 喜久男, 太刀川 恭治, 山田 穣, 村瀬 暁
    1984 年 48 巻 11 号 p. 1126-1131
    発行日: 1984年
    公開日: 2008/04/04
    ジャーナル フリー
    The critical current density, Jc, has been measured on NbTi-and VTi-based alloy superconductors in the temperature range between 4.2 and 1.8 K. Sample wires have been prepared in three different conditions; as cold-worked (CW), cold-worked and heat-treated (HT), and cold-worked, heat-treated and cold-worked (HT+CW). Cold working is effective in obtaining large Jc near the upper critical field, Bc2. A temperature scaling law on the flux pinning holds for each of wire preparation conditions in the form of Fp=K[Bc2(T)]nbp(1−b)q, where Fp is the flux pinning force density, b is the reduced field (=BBc2), and K, n, p and q are constants. The most faworable Jc properties are found in HT+CW wires where Fp=K[Bc2(T)]2b(1−b). On the basis of the pinning behaviour observed, some assignment of the individual constants in the scaling law equation is made to microstructural changes induced by cold working and heat treatment, and the reason why the marked improvement of current carrying capacities can be achieved in HT+CW alloy superconductors is discussed.
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