Transactions of the Japan Institute of Metals
Online ISSN : 2432-4701
Print ISSN : 0021-4434
ISSN-L : 0021-4434
Volume 26, Issue 4
Displaying 1-9 of 9 articles from this issue
  • Kenji Sumiyama, Tsutomu Yoshitake, Yoji Nakamura
    1985 Volume 26 Issue 4 Pages 217-224
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    Mössbauer spectra were obtained at 4.2 K and 290 K for the metastable bcc and fcc phases of sputtered Fe1−xCux alloys. For x=0–0.4 (the bcc phase region), a ferromagnetic sextet was observed at both 4.2 K and 290 K. The halfwidths of spectra are narrow and the average hyperfine field slightly decreases with increasing x. For x=0.6–1.0 (the fcc phase region), a sextet with very broad halfwidths was observed at 4.2 K. The average hyperfine field is smaller than that of the bcc alloys and gradually decreases with increasing x. At 290 K, where the fcc alloys are paramagnetic, a broad quadrupole splitting is detected, which can be decomposed into several contributions of Fe atoms with different numbers of nearest neighbor Fe atoms.
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  • Minoru Furukawa, Yasuhiro Miura, Minoru Nemoto
    1985 Volume 26 Issue 4 Pages 225-229
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    Deformation induced substructures of aged Al–Li alloys containing coherent δ′–Ll2 ordered particles have been studied by dark field transmission electron microscopy. Dislocations move in pairs when a fine scale precipitation of δ′ occurs. The observed shape of dislocations and the separation distance between the dislocations in a pair strongly depend on the size and distribution of δ′. Particles with diameter less than 50 nm are sheared by moving dislocation pairs. Dislocations by-pass the larger particles leaving dislocation loops.
    Planar arrangement of deformation induced dislocations, which is generally considered to be responsible for the poor ductility of the present alloys, has not been observed for any aging stage investigated in the alloy with a high Li content.
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  • Minoru Furukawa, Yasuhiro Miura, Minoru Nemoto
    1985 Volume 26 Issue 4 Pages 230-235
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    Strength of Al–Li alloys containing Ll2 ordered δ′-particles have been discussed on the basis of observed behavior of dislocations, taking into account various resistances to dislocation motion in the alloys. The measured yield strength and the observed arrangements of deformation induced dislocations are successfuly explained in terms of the dislocation-particle interaction theories. Main contributions to the strength of the alloys come from the energy of antiphase boundaries and the friction stresses in the ordered particles and in the matrix.
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  • Takashi Endoh, Mamoru Kawakami
    1985 Volume 26 Issue 4 Pages 236-241
    Published: 1985
    Released on J-STAGE: May 22, 2007
    JOURNAL FREE ACCESS
    Plane and rotating bending fatigue tests of boronized steels with various thicknesses of boronized layers were conducted. The effect of the thickness of boronized layer on the crack initiation and propagation mechanism was investigated by fatigue crack observation. Many cracks propagating perpendicular to the tensile axis and those propagating parallel to it with connecting each other to spall the boronized layer, were observed. Fatigue cracks were observed also in a specimen which was not fractured up to the cyclic number 107. But all those cracks were arrested either in the boronized layer or in a boundary between the boronized layer and the matrix. Fracture was controlled by whether the crack propagated through the boundary or not. Fatigue strength of boronized specimens with Fe2B uni-layer was higher than that of boronized specimens with FeB+Fe2B bi-layer. The maximun fatigue strength was obtained, when the volume of Fe2B layer was controlled so as to be about 1.5% of the total volume.
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  • Minoru Arita, Kunio Kamo
    1985 Volume 26 Issue 4 Pages 242-250
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    The dew points of phosphorus vapor over Sn–P alloys containing 45 mol%P or less have been determined at temperatures ranging from 703 to 973 K. The dew consisting of metastable liquid phosphorus, rather than stable red phosphorus, was utilized. The vapor pressures of P2 and P4 were determined from the dew points. Thermodynamic activities and enthalpies of P and Sn were calculated from the vapor pressures. The liquidus line was determined from the temperature and composition dependence of the vapor pressure over coexisting liquid and Sn4P3.
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  • Mototaro Sato, Takao Yamazaki, Makoto Kubo
    1985 Volume 26 Issue 4 Pages 251-258
    Published: 1985
    Released on J-STAGE: May 22, 2007
    JOURNAL FREE ACCESS
    This paper describes the effects of the crystal orientation upon the cutting mechanism and the theoretical analysis of experimental results by the distortion method. The experiment was performed by the orthogonal cutting of an aluminum single crystal having the (001) plane and (110) plane. The single crystal was produced by the Bridgman method, and the crystal orientation was determined by the Laue X-ray back reflection method.
    (1) The experimental results showed that the effects of the orientation appeared clearly on the cutting phenomenon. That is, the cutting force Ks, the shearing angle and the finished surface vary with the change in the cutting direction.
    (2) It is clarified that the mechanism of the formation in the shear zone is reasonably explained by the distortion method based on the slip system of the crystal.
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  • S. K. Majumdar, R. A. Tewari, B. K. Dhindaw
    1985 Volume 26 Issue 4 Pages 259-270
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    The superplastic behaviour of Zn–Al eutectoid and near eutectoid alloys was investigated in the present study with the help of statistical design of experiment. The first part of the paper describes quantitatively the singular and joint effects of strain rate, temperature, grain size and Al–content on the total ductility and maximum flow stress, when all of them were varied simultaneously at constant levels of different processing factors. An adequate regression model for predicting total ductility in the given ranges of variation of strain rate, temperature, grain size and %Al was also developed. The regression equation was exploited to locate the optimum region of total ductility by applying an appropriate optimisation technique. The second part of the paper presents the effects of different processing factors on total ductility. These effects were evaluated by varying simultaneously all the processing factors in the near-optimum region of ductility.
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  • Teruo Takahashi, Yasuhiko Hashimoto, Shinichiro Omori, Koichiro Koyama
    1985 Volume 26 Issue 4 Pages 271-279
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    Dilute Cu–Al, Cu–Ti and Cu–Al–Ti alloys internally oxidized over the temperature range 1073–1323 K were investigated by X-ray diffractometry, optical and electron microscopy and microvickers hardness testing.
    From X-ray diffractometry of the nitric-acid-treated residues, γ- and α–Al2O3 and CuAlO2 were identified in internally oxidized Cu–Al alloys and rutile and anatase type TiO2 in internally oxidized Cu–Ti alloys. In internally oxidized Cu–Al–Ti alloys, all of the oxides observed in the both above Cu–Al and Cu–Ti systems were identified, and no other complex oxides were detected.
    By electron microscopy, it was revealed that the particle size of dispersed oxide was remarkably decreased with addition of a small amount of titanium into Cu–Al alloy. In accord with the results from electron microscopy, the microvickers hardness increased with the mass ratio of TiO2 to total oxide.
    The internally oxidized Cu–Al–Ti alloys possessed excellent qualities that belonged to the internally oxidized Cu–Al and Cu–Ti alloys.
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  • Noboru Yoshikawa, Hajime Suto
    1985 Volume 26 Issue 4 Pages 280-287
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    It is well known that the stress induced martensitic transformation is responsible for the high strength of partially stabilized zirconia (PSZ). In the present study, conventionally sintered (CS) and hot-pressed (HP) commercial PSZ compacts with 2.5 mol% Y2O3 were used as original materials. After annealed at various temperatures, transformation behaviors during cyclic annealing were investigated by dilatometory. In addition, bending test was carried out for HP specimens subjected to cyclic annealing. The results are as follows: (1) The dominant constituent phases in as-received and as-annealed specimens were tetragonal and cubic, except a few cases. (2) The tetragonal phase (t-ZrO2) in as-received PSZ was stable up to 1573 K. But in the specimens pre-annealed at higher temperatures, the retained t-ZrO2 transformed to the monoclinic phase (m-ZrO2) at about 500 K, and then transformation from monoclinic to tetragonal (m-t) took place at about 850 K on the first heating. This t-ZrO2 easily transformed to m-ZrO2 at about 700 K on the subsequent cooling. (3) The stability of t-ZrO2 in as-annealed specimens is influenced by the segregation of Y in the original state. (4) The mean value of transverse rupture strength of HP–PSZ was decreased by thermal cycles of 100 times up to 1553 K.
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