Transactions of the Japan Institute of Metals
Online ISSN : 2432-4701
Print ISSN : 0021-4434
ISSN-L : 0021-4434
Volume 26, Issue 11
Displaying 1-9 of 9 articles from this issue
  • Tohru Takahashi, Ryo Horiuchi
    1985 Volume 26 Issue 11 Pages 779-785
    Published: 1985
    Released on J-STAGE: May 22, 2007
    JOURNAL FREE ACCESS
    Bicrystal experiments were carried out, in order to verify the DSC dislocation model of grain boundary sliding. Coupling of sliding and migration was observed in the {1\bar211} coincidence boundary of Zn. The amount of grain boundary migration was measured to be about twice as large as that of grain boundary sliding. The sliding-to-migration ratio as well as the migration direction were in agreement with those predicted by the DSC dislocation model.
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  • Tohru Takahashi, Ryo Horiuchi
    1985 Volume 26 Issue 11 Pages 786-794
    Published: 1985
    Released on J-STAGE: May 22, 2007
    JOURNAL FREE ACCESS
    Grain boundary sliding behavior was investigated in coincidence boundaries of Zn and Al bicrystal specimens, in order to demonstrate the applicability of the DSC dislocation model. Two coincidence boundaries, viz. a ⟨10\bar10⟩ symmetric tilt boundary with a {1\bar216} boundary plane in Zn and a ⟨1\bar10⟩ symmetric tilt boundary with a {113} boundary plane in Al, were examined. Coupling of sliding and migration was observed on both boundaries. The ratio of the amount of grain boundary migration to that of grain boundary sliding was measured to be about 8 for the Zn {1\bar216} boundary and about 3 for the Al {113} boundary. The ratios and the migration directions were in accordance with the theoretical prediction based on the DSC dislocation model.
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  • Hideaki Murata, Hajime Asano, Fujio Izumi, Shoichi Tomiyoshi, Hirokats ...
    1985 Volume 26 Issue 11 Pages 795-798
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    The crystal structure of Ta2D has been refined on the basis of neutron diffraction data taken by a high-resolution powder diffractometer HRP at the KENS pulsed neutron source. The diffraction pattern contains as much as 279 reflections covering a d-range of 0.05–0.28 nm. From the Rietveld analysis, a tantalum atom displacement induced by the ordered deuterium arrangement has been refined as 0.0059±0.0002 nm.
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  • Masami Onishi, Toshitada Shimozaki
    1985 Volume 26 Issue 11 Pages 799-805
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    Characteristics of the diffusion flux referred to the coordinate system fixed with respect to the solid surface of a vapor-solid diffusion couple have been precisely investigated in relation to the Matano method. The analysis method to obtain the interdiffusion coefficients in a vapor-solid diffusion couple in which a high vapor pressure component diffuses out from a binary alloy specimen through vapor phase has been presented.
    The coordinate system fixed with respect to the solid surface may be usefull for the metallic cementation such as siliconizing and boronizing of steel or iron specimens, and the diffusion coefficient, βi, referred to the coordinate system will serve to draw the penetration profiles in the specimens, instead of the interdiffusion coefficients. From the viewpoint of the vacancy formation and disappearance at the solid surface, it is discussed that the inter-and intrinsic diffusion coefficients determined in the vapor-solid couples become larger than those obtained in an ordinary semi-infinite solid-solid diffusion couple in magnitude.
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  • Koji Tanoue, Yasushi Umemoto, Hidehiko Matsuda
    1985 Volume 26 Issue 11 Pages 806-813
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    Measurements of the electrical resistivity, Simple tensile tests and stress relaxation tests are made to investigate the hardening mechanism at the early stage of ageing in Al–Zn alloys. There exists a good linear relationship between the flow stress and the square root of the plastic strain, ε1⁄2, at any stage of ageing for pure Al and Al–Zn alloys deformed at \dotε=10−4s−1 and 77 K. The strain independent flow stress σ0 obtained by extrapolating ε1⁄2 to zero increases drastically in the concentrated alloys as ageing proceeds. This initial agehardening can be explained by the increment in internal stress due to the interaction between dislocations and the coherent strain fields as proposed by Gerold et al.
    The strain exponent n of the activation volume for dislocation motion is obtained to be n1=−0.3 and n2=−0.6 on both sides of a certain strain εc for the alloys on the assumption that V*∝εn. The dislocation intersection mechanism can give a satisfactory explanation for n2\simeq−1⁄2. The reason why n1 does not coincide with n2 may be that parallel processes of the dislocation intersection and the shearing of GP zones by dislocations rate-controll the deformation in the strain region less than εc.
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  • Yutaka Hiraoka, Tadayuki Fujii, Masatoshi Okada, Ryoji Watanabe
    1985 Volume 26 Issue 11 Pages 814-824
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    Tensile tests at 77, 173 and 293 K were performed on molybdenum single crystals having axial-orientations near the ⟨011⟩-direction, which had been prepared by the secondary recrystallization method. The effect of “island grains” at the crystal surface and/or in the bulk, and the effect of test temperature on the crack generation and propagation characteristics were investigated.
    At 77 and 173 K, cracks were generated from “island grains” for all of annealed or polished specimens and for most of carburized specimens. The plane on which the cracks propagated was initially the {011}-plane and afterwards changed to the {112}-and/or {001}-planes, though the {011}-plane component just around the crack generation sites tended to diminish or vanish in polished or carburized specimens. The fracture strength of annealed or polished specimens depends on the size of “island grain” from which the crack was generated. On the other hand, the strength of carburized specimens was appreciably enhanced by addition of a small amount of carbon and was apparently not size-dependent.
    At 293 K, cracks which were not propagated were observed at the interfaces between the “island grains” and the matrix in annealed or polished specimens. However, any “island grains” were not responsible at all for the final failure of the crystals. All the specimens failed after having shown considerably high ductility.
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  • Federico Chavez, Ryo Inoue, Hideaki Suito, Masayasu Ohtani
    1985 Volume 26 Issue 11 Pages 825-831
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    The EMF method by solid electrolyte (ZrO2+9 mol% MgO) was used for the determination of the activity of FetO in the CaF2–CaO–FetO (1673–1733 K) and CaCl2–CaO–FetO (1623–1673 K) systems. No appreciable effect on the FetO activity was found, when FetO was replaced by CaF2 or CaCl2 at a constant CaO content. The Fe3+/Fe2+ ratio, on the other hand, was found to increase with increasing CaF2 content and to decrease with increasing CaCl2 content at a constant CaO content.
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  • Ji Chunlin, Qi Guojun
    1985 Volume 26 Issue 11 Pages 832-839
    Published: 1985
    Released on J-STAGE: June 01, 2007
    JOURNAL FREE ACCESS
    Fe–C–Si ternary melt was studied experimentally by establishing an iso-silicon-activity state for ternary samples through a common silver bath. A method for evaluating a set of self-consistent activity interaction coefficients in Fe–i–j systems has been proposed. Its application to Fe–C–Si ternary melt yields
    ln γSi0=−7.21, εSiSi=17, ρSiSi=−8, εSiC=6.5, ρSiC=−4 and ρSiC,Si=−5,
    and hence the activity coefficient of silicon can be expressed as:
    ln γSi=−7.21+17XSi−8XSi2+6.5XC−4XC2−5XSiXC.
    It has been shown that Darken’s ternary quadratic equations are incapable of evaluating the activity coefficients of silicon and carbon in Fe–C–Si melt due to the inconsistency of αSi-C. However, in combination with eqs. (18) and (23) in the text, the ternary quadratic formalism becomes useful for estimating logγSi along each iso-silicon-activity line.
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  • Masanobu Ohmori, Misao Itoh, Masahiro Fujita
    1985 Volume 26 Issue 11 Pages 840-848
    Published: 1985
    Released on J-STAGE: May 22, 2007
    JOURNAL FREE ACCESS
    In order to examine the effect of the pressure on the formability of a steel plate in the explosive forming processes, a ring specimen taken from a long cylindrical cup with a very low critical impact tensile velocity was explosively expanded in water by the use of a detonator, and a tensile specimen prepared from the same cup was tested after exposed in water to the explosive pressure. The present experiments revealed that the formability of the steel plate in the explosive forming operations was favorably affected by the explosive pressure.
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