日本金属学会誌
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
62 巻, 1 号
選択された号の論文の17件中1~17を表示しています
  • 田口 英次, 伊東 隆介, 赤塚 雅則, 角田 直人
    1998 年 62 巻 1 号 p. 1-8
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    Fine damage structure induced by electron irradiation in Al2Au was studied with an electron microscope. Irradiation was done with 3.2044×10−13 J(2 MeV) electrons at 170 K and room temperature using a high voltage electron microscope.
    Secondary defects such as dislocation loops are not formed at the irradiated region but a dotted structure developped there. Unknown intensity distribution appears in the diffraction pattern. It suggests that the fine structure is different from Al2Au. Taking the diffraction patterns and the X-ray spectra observed at the different parts of the irradiated region into consideration, the crystal phases formed by the irradiation were identified to be Al and AlAu. The orientation relationships between Al, AlAu and the matrix(Al2Au) exist as the followings,
    (This article is not displayable. Please see full text pdf.)
    It was concluded that the Au atoms diffuse towards the periphery of the irradiation area caused the phase change.
  • 橋本 哲, 安藤 聡, 浦川 隆之, 鷺山 勝
    1998 年 62 巻 1 号 p. 9-14
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    The crystal structure of the electrodeposited Zn-Cr coating has been analyzed by using X-ray diffraction. The electrodeposited Zn-Cr coating has η′-Zn phase under the content of about 8 mass%Cr, it has γ′-ZnCr phase over about 15 mass%Cr and the two phases co-exist between 8 and 15 mass%Cr. The lattice constant of the a-axis for η′-Zn phases having hcp structure increases and that of the c-axis decreases as a function of Cr content. The crystal structure of the γ′-ZnCr phase is close to that of Cu5Zn8 type structure. η′-Zn and γ′-ZnCr are nonequilibrium phases. After the as-deposited Zn-Cr coatings are heated at 260°C for 5.4 ks, the coating of 0.8 mass%Cr transforms to η-Zn phase and those of more than 5.7 mass%Cr transform to ζ-ZnCr phase. ζ-ZnCr phase which has not been reported in the Zn-Cr binary alloy system has CoZn13 type structure.
  • 吉池 彰吾, 安達 弘通, 市野瀬 英喜, 徳満 和人, 井野 博満, 白鳥 紀一
    1998 年 62 巻 1 号 p. 15-21
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    Non-equilibrium Pr100−xFex alloys (x=1∼40) prepared by melt-quenching were investigated by X-ray diffraction, VSM, Mössbauer spectroscopy and TEM observation. The experimental results indicated that, in the Pr-1 at%Fe alloy, iron atoms have little magnetic moment and may be dissolved in a dhcp-Pr matrix. In other compositions, iron atoms, having a magnetic hyperfine field of about 29 T (290 kOe) at 77 K, are mainly in an amorphous phase. We analyze the magnetic data for Pr-10, 20, 30 at%Fe with the model based on super-ferromagnetism —magnetically connecting Fe-rich clusters dispersed in a non-magnetic matrix—, in which the inter-cluster interactions are treated as molecular field. The results show that the Curie temperature within clusters, Tcintra, is nearly constant for all compositions, and that for inter-cluster coupling, Tcintra, becomes higher toward Tcintra as the iron concentration increases. The analysis also shows that the average size of clusters increases with the iron concentration. It is suggested that the patches in an amorphous region observed in the TEM image of Pr-10 at%Fe, each of which is estimated to contain a few hundreds of atoms and behaves as the super-ferromagnetic clusters.
  • 王 占杰, 関 史江, 伊藤 邦夫
    1998 年 62 巻 1 号 p. 22-29
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    In order to study formation mechanism of the preferred orientation during annealing after swaging in the alloy prepared by extrusion of gas atomized powders, swaged and recovered structures as well as structure of recrystallization fronts were observed by transmission electron microscopies. The [110] oriented recrystallizing grains are found to originate from those cells in the deformed structure that contain high density Al-Fe compound particles. In the case of [110] oriented recrystallizing grains, their {111} planes are nearly parallel to {110} planes of the both [111] and [110] oriented matrix grains, making a wedge-shaped recrystallization front moving in the longitudinal direction. The specially oriented wedged-shaped front is free from particles, while any other recrystallization fronts are pinned down by particles either precipitating on themselves or precipitated in the recovered matrix. High resolution transmission electron micrographs suggest that the migration of the specially oriented interface normal to the interface plane proceeds by formation of {111} plane steps on the interface preceded by migration of grain boundary triple point and their following movement in the interface plane. The formation of the preferred orientation has been inferred to be associated with high mobility of the recrystallization front of the [110] oriented grains in the longitudinal direction in relation with the special structure of the front.
  • 川森 重弘, 佐々木 伸行, 石川 文敬, 南雲 道彦, 奥村 達志, 飴山 惠
    1998 年 62 巻 1 号 p. 30-36
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    Microstructure and tensile properties at elevated temperatures of fine composites prepared by mechanical alloying of Ti and SiC powders have been investigated. Mixtures of elemental Ti and SiC powders in the composition of Ti-24 mass%SiC are milled under an Ar atmosphere using an attritor ball mill. After milling for 36 ks, formation of TiC and Ti5Si3 is observed and further milling adding n-heptane for 3.6 ks makes the powder particles finer. Milled powders are consolidated by hot pressing at 1773 K for 10.8 ks under 70 MPa and hot isostatic pressing at 1773 K for 10.8 ks under 196 MPa. The compact consists of mostly equi-axed TiC and Ti5Si3 grains of an average diameter of 0.86 μm partially mixed with plate-like phase of Ti3SiC2. The compact shows elongation of 130% at tensile test at 1773 K with an initial strain rate of 4.0×10−4 s−1 with the strain rate sensitivity exponent of 0.38. Most grains remain equi-axed after tensile test, while random orientations of plate-like phases of Ti3SiC2 turn parallel along the tensile axis. The large elongation observed above 1773 K is likely due to the superplasticity, while rotation of the plate-like phase accompanies deformation of the surrounding matrix.
  • 小池 俊之, 田中 康介, 大塚 正久, 山縣 裕
    1998 年 62 巻 1 号 p. 37-43
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    Constant-compressive-load creep testing on [111] single crystals of 99.999 mass% purity aluminum was carried out at 473 and 533 K. Rapid increases in the creep rate (strain burst) were observed under the stress ranging from 15 to 30 MPa at 473 K. The strain burst was also observed at 533 K under 10, 15 and 20 MPa, but there was the less increase in the strain at the strain burst. Microstructural observations revealed that the strain burst is caused by dynamic recrystallization accompanying rapid grain growth of a few grains. It was confirmed that dynamic recrystallization takes place during the creep testing of high purity aluminum.
  • 渡辺 祥史, 小池 俊之, 大塚 正久, 山縣 裕
    1998 年 62 巻 1 号 p. 44-49
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    Tensile testing on 99.999 mass% purity aluminum was carried out in the temperature range of 413 to 653 K. The deformation behavior of single crystals of three orientations was compared at the initial strain rates of 1.67×10−4, 1.67×10−3 and 1.67×10−2 s−1. Typical stress oscillations inherent to the discontinuous dynamic recrystallization were observed.
    Microstructural observation detected dynamically recrystallized grains containing subgrains. It was confirmed that dynamic recrystallization takes place even at the tensile testing showing macroscopically homogeneos deformation mode. The activation energy on the rate controlling process was calculated from the temperature and strain rate dependence of the first peak stress of the stress oscillation. The obtained value 140+⁄−10 kJ· mol−1 was near the activation energy for the self diffusion of aluminum.
  • 栗田 洋敬, 山縣 裕
    1998 年 62 巻 1 号 p. 50-55
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    The fretting wear characteristics of JIS-AC9B and JIS-AC8A aluminum alloys were evaluated using a fretting wear testing machine in order to reveal the effect of the hardness on the fretting wear resistance. An oscillatory normal load (98 N) combined with a rotational vibration (6.8×10−2 rad) was imposed on the contact region between a spherical rider (case-hardened steel) and a flat rotor (JIS-AC9B or JIS-AC8A). The hardnesses of the rotor specimens were varied by changing the aging time at 523 K. The wear scar area of JIS-AC9B and JIS-AC8A was decreased linearly with increasing the rotor hardness at both room temperature and 523 K. It was considered that the adhesive wear mechanism was dominant in the fretting wear process of these alloys.
  • 赤池 淳, 本郷 和弘, 松田 則男, 松浦 圭助
    1998 年 62 巻 1 号 p. 56-63
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    Creep tests have been carried out on the 6061Al matrix composites reinforced with 10 and 20 vol% of alumina particles to examine the effects of reinforcements on the creep properties. Furthermore, the density change was measured, and microstructures and fracture surfaces were observed after the creep deformation to get the information about the creep damages, or the formation of creep cavities.
    Creep curves were generally dominated by the tertiary creep at 573 K and 673 K, although the increased extent of normal primary creep was recognized at high stresses of 573 K. Inverse transient creep followed by normal primary creep of large strain (S type curve) was observed in the low stress region of 773 K. In this case, the matrix alloy was elongated like filaments at the edge of dimples or grain boundaries in the fracture surface, which suggested that a very soft material was formed at the particle/matrix interfaces or grain boundaries and elongated during the creep deformation.
    Minimum creep rate was almost same in the both composites of 10 vol% and 20 vol% alumina particles, that is, it did not depend on the volume fraction of particles. In comparison with the 6061Al alloy reinforced with the same volume fraction of short alumina fibers, the minimum creep rate of this composite was smaller than that of the particle reinforced 6061Al at 673 K and 773 K, while the minimum creep rate was almost same in both composites at 573 K.
    The density of specimens decreased largely with creep time and creep strain after creep at 773 K. Particularly, an evident density decrease was recognized when the S type creep curve occured at low stress of 773 K. In this case, creep cavities extended largely due to the formation of soft material (supposed to be a semi-liquid phase or solid oxide formation) at the particle/matrix interfaces and grain boundaries.
  • 土井 教史, 山下 正人, 長野 博夫
    1998 年 62 巻 1 号 p. 64-70
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    Atmospheric corrosion and in-door corrosion are the types of corrosion which is expedited under thin water film and are observed on various kinds of metal structures and equipments. Too many factors controlling these phenomena have hindered us from looking into the corrosion of steel under thin water film. Then, water adsorption onto material surfaces and kelvin potential change as a function of relative humidity were investigation for pure iron, SUS304, Ni and Cr. It is thought that clarifying those phenomena makes it possible to more clearly understand a corrosion behavior under thin water film.
    Water adsorption increases with RH. And hydroxyl groups are influencial for water adsorption on metal surfaces. Moreover, Kelvin potential for metal is understood to fall with water adsorption. Observing changes of water adsorption and Kelvin potential behavior, on metal surfaces can afford to make access to fundamental understuding of atmospheric corrosion.
  • 篠崎 信也, 園田 正樹, 向井 楠宏
    1998 年 62 巻 1 号 p. 71-75
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    The surface tension and the wettability of molten metal-ceramic system, which are the indispensable parameters in considering molten metal infiltration into pores of ceramics, have been studied by the use of the sessile drop method. Manganese and zirconia ceramics containing yttoria were prepared as the metal and the ceramic, respectively.
    The surface tension of molten manganese was approximately 1.1 N/m at 1573∼1773 K. The contact angle was in the range of 74°∼86°, suggesting that this metal-ceramic system had a good wettability. Manganese diffused into zirconia matrix. Estimating the bond strength at interface, it was presumed that not only intermolecular force but also chemical interaction force contributed to the interfacial bond.
  • 宇田 哲也, 岡部 徹, 早稲田 嘉夫
    1998 年 62 巻 1 号 p. 76-84
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    The Long Range Electronically Mediated Reaction (LR-EMR) has been tested for controlling the location of titanium deposit during magnesiothermic reduction of TiCl4. An iron cathode tube immersed in molten salt was electrochemically connected with Mg-18 mol%Ag liquid alloy placed at the bottom of an anode crucible through an external circuit. When TiCl4 was fed into the cathode tube at 1073 K, electrochemical reduction of TiCl4 was confirmed by detecting current in the external circuit. This titanium reduction is attributed to LR-EMR because the concentration of silver is less than 50 mass ppm in the resultant titanium deposit, despite Mg-Ag alloy was used as the reductant. In this work, 70% of titanium deposit could be localized at the vicinity of cathode by adjusting the experimental conditions such as configuration of electrodes and molten salt compositions. Such localized deposition on the cathode tube was found to increase up to 80% by decreasing TiCl4 feed rate. The conventional Kroll process is known to be difficult to control the location of titanium deposit during metallothermic reduction. However, the LR-EMR concept can bring about a significant breakthrough in this difficulty, as it has been demonstrated in this work. The present results also stimulate the development of semi-continuous titanium reduction process possible when applying LR-EMR.
  • 吉田 誠, 村尾 伸介, 青井 一郎, 中江 秀雄
    1998 年 62 巻 1 号 p. 85-91
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    To investigate the influence of gravity on the microstructure of directionally solidified Al-In monotectic alloy, downward U.D.S.(direction to gravity) and upward U.D.S.(opposite direction to gravity) was carried out. To realize downward U.D.S., zone-melting method was introduced in order to eliminate cavity which inevitably appears in front of solid/liquid interface in current Bridgman method. A hyper-monotectic alloy, Al-18.0 mass%In, was used to examine gravitational segregation on both primary and monotectic L2(In) phases.
    (1) The gravitational macro-segregation and their condensation of primary L2 liquid were observed at the bottom of molten alloy in the downward U.D.S. In the case of the upward U.D.S., the primaries dispersed in aligned monotectic morphology. On the monotectic reaction, macro-segregation of L2 liquid growing cooperatively with α(Al) phase was not observed neither in upward nor in downward U.D.S. However, the morphology in downward U.D.S. had a tendency to form so called “banded structure”.
    (2) In-rich layer with the length of several hundred mm was found in front of solid/liquid interface. The length of In-rich layer in downward U.D.S. was twice longer than in upward U.D.S. in each 6 level growth rate, 1∼32 mm/h.
    (3) Influence of growth rate to the interphase spacing between fibrous monotectic In phases reveal no remarkable difference between upward and downward U.D.S.
  • 菅沼 克昭, Saiz Eduardo, Tomsia Antoni P.
    1998 年 62 巻 1 号 p. 92-97
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    The interface strength and microstructure of α-alumina/pure aluminum were evaluated. In a solid-state joining, the strength of the joint increases with increasing joining temperature. In a liquid state joining, the strength gradually decreases due to the formation of an unjoined area. The strength,σb, is expressed by the following equation as a function of the unjoined area, A: σb=2.22A+143 (70%≤A≤100%). The highest strength reached 400 MPa when the interface is formed at around the melting temperature of aluminum. An aluminum layer becomes a single crystal when it is joined to a sapphire. The following crystallographic orientation relationship is established:
    (This article is not displayable. Please see full text pdf.)
    Amorphous alumina islands are formed at the interface. In the amorphous alumina, spinel nano crystals grow from the sapphire and they have the same orientation relationship with sapphire as above.
  • 井手 幸夫, 稲田 和典, 中村 崇, 前田 正史
    1998 年 62 巻 1 号 p. 98-105
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    Ti-Al-N films were deposited using an activated reactive evaporation (ARE) method with single vapor source of Ti-Al alloys. The behavior of some species excited and ionized in the plasma and a relationship between these reacting species and important operating parameters of ARE such as a probe voltage were investigated by optical emission spectroscopy(OES) and mass spectrometry(MS). The films were characterized by XRD, EPMA and AES. A high temperature oxidation of Ti-Al-N films were studied in air at temperatures from 600 to 1000°C. The results were summarized as follows.
    (1) Each of emission lines from titanium, aluminum and nitrogen by OES could be detected without interferences.
    (2) Since TiN+ was observed by MS during TiN and Ti-Al-N film formation, TiN was considered to be synthesized in the plasma.
    (3) The Ti/Al ratios of Ti-Al-N films analyzed by EPMA showed a good correlation to the Ti/Al ratios monitored by OES and MS respectively.
    (4) The resistivity to oxidation of Ti-Al-N films increased with increasing Al content in the films.
  • 藤野 茂, 井尻 英幸, 清水 史幸, 森永 健次
    1998 年 62 巻 1 号 p. 106-110
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    The viscosity-temperature behavior in the wide range 10−2∼1012 Pa· s were presented for various glass systems: oxide, fluoride, halide, and chalcogenide. There is no single technique that can be utilized to measure the viscosity of glass over the entire range, spaning roughly 14 orders of magnitude. The viscosity was measured by a penetration viscometry method at low-temperature viscosity region (107∼1012 Pa· s) and by a rotational viscometry method at high-temperature viscosity region (10−2∼10−1 Pa· s). It was found the viscosity can be expressed by the Cohen-Grest equation over a wide temperature. The working point, Tw(103 Pa· s), the softening point, Ts(106.65 Pa· s) and the working range-temperature interval between the Tw and the Ts were determined using the measured viscosity data and the viscosity-temperature equation. We discussed the technical term of fiber drawing from the viewpoint of viscosity-temperature behavior and thermal stability of glass crystalized as a function of heat treatment time, tD at the drawing temperature. The results indicate that silica and lead silicate glasses are prefered for fiber drawing.
  • 古牧 政雄, 天野 宗幸, 沼田 英夫, 西村 睦
    1998 年 62 巻 1 号 p. 111-116
    発行日: 1998年
    公開日: 2008/04/24
    ジャーナル フリー
    Thermal desorption spectrometry (TDS) was carried out for hydrogenated samples of Mg0.9Ni0.1, Mg0.77Ni0.23 and Mg0.78Ni0.20Al0.02 in the temperature range of 298 to 723 K. Two kinds of samples were prepared for each alloy: samples not exposed or exposed to air after hydrogenation. Two peaks overlapped in each TDS curve. The low temperature peak is caused by the decomposition of Mg2Ni or Mg0.73Ni0.26Al0.01 hydride and the high temperature peak is caused by the decomposition of Mg hydride. The peak-shift of both peaks after the air-exposure was less than 50 K for the hydrogenated Mg0.77Ni0.23 and Mg0.78Ni0.20Al0.02, while the peak-shift of the hydrogenated Mg0.9Ni0.1 was very large, especially for the high temperature peak, i.e., more than 100 K. The hydrides of Mg2Ni and Mg0.73Ni0.26Al0.01 phases kept their activity for hydrogen desorption even after the air-exposure. It is considered that the hydride surface of primary Mg crystals is easily oxidized and becomes inactive, while Mg hydride in the eutectic is densely surrounded by Mg2Ni hydride and sintering process between both phases during hydriding-dehydriding treatment occurs, and hydrogen in the Mg hydride desorbs through the Mg2Ni or Mg0.73Ni0.26Al0.01 phase.
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