Journal of the Japan Institute of Metals and Materials
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
Volume 51 , Issue 12
Showing 1-17 articles out of 17 articles from the selected issue
  • Masahiko Itoh, Shoji Onose, Shunichi Yuhara
    1987 Volume 51 Issue 12 Pages 1101-1107
    Published: 1987
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    Formation of the ferritic phase was observed in 10% cold-worked Type 316 stainless steel specimens at temperatures ranging from 680 to 790 K by neutron irradiations up to a fluence of 6.4×1026 m−2 (E>0.1 MeV) in the experimental fast reactor “JOYO”. The ferritic phase dissolved on further irradiation. With increase in irradiation temperature, the formation and dissolution of the ferritic phase occurred at lower fluences.
    The ferritic phase formed adjacent to M6C precipitated at grain and twin boundaries in steels at an early stage of irradiation. The M6C precipitate is evidently enriched by solute elements. The enrichment of Ni in the M6C is thought to induce the ferritic phase formation in a Ni-depleted region. As the neutron fluence increased, Ni is supplied to the grain boundary by a radiation-induced segreation mechanism. This Ni segregation to the grain boundary appeares to annihilate the radiation-induced ferritic phase.
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  • Fukuji Inoko, Minoru Kobayashi, Shiro Kawaguchi
    1987 Volume 51 Issue 12 Pages 1108-1115
    Published: 1987
    Released: April 04, 2008
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    In order to clarify the effect of edge dislocation on the occurrence of the strain induced boundary migration (SIBM), aluminum bicrystals with a ⟨211⟩ tilt grain boundary were examined.
    Two types of 99.99 wt% aluminum bicrystals were prepared by using “soft-mold” Bridgman technique. All bicrystals were pulled to a tensile strain 3×10−1 at room temperature and annealed at 753 K for 480 s, at the same temperature for 960 s and finally at a higher temperature of 793 K for 300 s, in vacuum.
    It was found that many new grains were formed by the SIBM of the ⟨211⟩ tilt grain boundaries in all the bicrystals except for the type 1 bicrystal with a small misorientation. This result exhibited a contrast to the previous one in that in the aluminum bicrystals with a {111} or {211} twist grain boundary the generation of many new grains with the ⟨111⟩ rotation was observed at the pre-existing boundaries. The new grains due to the SIBM mutually barged into the adjoining crystal and then preferentially grew along the deformation bands. It should be noted that the new grains due to the SIBM do occur in the bicrystals in which the edge dislocations were piled-up to the pre-existing boundaries by the tensile deformations.
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  • Naotsugu Inakazu, Yasuyuki Kaneno
    1987 Volume 51 Issue 12 Pages 1116-1124
    Published: 1987
    Released: April 04, 2008
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    The influence of iron in the solid solution on recrystallization behavior of a high purity drawn aluminium has been investigated by means of the measurements of mechanical and electrical properties, the determination of X-ray pole figure and ODF, and transmission electron microscopy.
    By drawing to 90% reduction in area, a duplex fiber texture composed of a strong ⟨111⟩ axial component and a weak ⟨100⟩ one is formed in pure aluminium, while the ⟨111⟩ fiber texture is formed in the precence of a minute amount of iron. In the case of high temperature annealing (723 K), precipitation occurs after recrystallization, and the ⟨111⟩ axial component remains. This seems to be caused by the segregation of iron in the sub-grain boundaries. In the case of medium temperature annealing (648 K), precipitation occurs before recrystallization. In the case of low temperature annealing (573 K), the recrystallization and the precipitation behavior occur simultaneously. In both cases, the increment of the ⟨100⟩ fiber axial component is suppressed and the ⟨111⟩ one remains in the matrix because of the pinning of a migrating sub-boundaries by fine precipitates.
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  • Hideki Iba, Shigeoki Saji, Takumi Sogabe, Shigenori Hori
    1987 Volume 51 Issue 12 Pages 1125-1132
    Published: 1987
    Released: April 04, 2008
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    In connection with spinodal decomposition, the nucleation and growth of cells formed by grain boundary reaction during aging at 673 and 773 K were investigated in Cu-34 mass%Ni-14 mass%Fe and Cu-44 mass%Ni-18 mass%Fe alloys by means of optical and transmission electron microscopy. The results obtained are as follows. Nucleation and growth of grain boundary cell occur remarkably in the later stage of spinodal decomposition in which the wavelength of the modulated structure is unchanged, the amplitude of compositional fluctuation increases and the sine wave of concentration profile of solute atom changes to the square one. In the initial stage of cell formation, the average spacing between the fibrous precipitates is roughly double the wavelength than the wavelength (about 5 nm) of the modulated structure. Nucleation and growth rates of the cells become negligibly small in the later stage of aging in which the coasening reaction of the modulated structure progresses remakably. The driving force for cell nucleation and growth is mainly the difference of total interfacial energy between the fibrous precipitates within cells and the compositional fluctuation or zones in the modulated structure. The activation energy obtained for the cell formation (about 95 kJ/mol) is much smaller than that for the coasening reaction of the modulated structure in these alloys (about 180 kJ/mol). We proposed a model for the cell formation mechanism in these alloys.
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  • Tadakazu Ohnishi, Taichiro Ito
    1987 Volume 51 Issue 12 Pages 1133-1138
    Published: 1987
    Released: April 04, 2008
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    Mechanical properties of a commercial Al-Li-Cu-Mg-Zr alloy aged at 453 K were investigated with a particular emphasis on the effects of cathodic hydrogen charging. Significant hydrogen permeation into the specimen was observed for under-aged conditions, while limited permeation for over-aged conditions. This alloy showed a two-stage hardening behavior upon aging at 453 K, and the effect of hydrogen charging on the tensile properties was observed to differ for each stages; in the first stage a slight strengthening was found, and in the second stage a slight embrittling tendency was observed. The Young’s modulus of the alloy, which was considerably higher in the solution-heat-treated state than those of other high strength aluminum alloys, was gradually lowered by aging and also by hydrogen charging. The optimum balance in the mechanical properties under an influence of hydrogen is expected to be obtained at a slightly under-aged condition.
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  • Hidekazu Sueyoshi, Katsuro Suenaga, Ryohei Tanaka
    1987 Volume 51 Issue 12 Pages 1139-1144
    Published: 1987
    Released: April 04, 2008
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    The mechanism and critical conditions for crack initiation of ductile fracture of hypo-eutectoid graphitic steels were studied in the round bar specimens pulled in tension.
    In the centre of the necked part of a tensile specimen, voids which nucleated at the interface between the matrices and graphite nodules grow both in longitudinal and transverse directions because of a triaxial tensile stress.
    In the next stage of tension, a central crack is formed by coaleacence of voids due to the microvoids formation in the matrix between large voids. This crack spreads rapidly in the transverse direction, but near the surface the crack propagates in a direction inclined at about π/4 radian to the tensile axis.
    A critical condition for the central crack initiation is expressed as follows:
    (This article is not displayable. Please see full text pdf.)
    \ oindentwhere σm⁄\barσ is a stress triaxiality in the centre of the necked part, lV and ρV are a spacing and a radius of curvature of the large voids located in the centre of the necked part, respectively, and C is constant.
    A dependence of the ductile fracture strain upon microstructure may be attributed to the void dependency mentioned above.
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  • Toshio Shimoo, Tatsuyuki Okamoto, Shigeru Ando, Hiroshi Kimura
    1987 Volume 51 Issue 12 Pages 1145-1151
    Published: 1987
    Released: April 04, 2008
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    The rate of reduction of Cr2O3 by solid carbon has been investigated at high temperature from 1743 to 1993 K, and under an argon atmosphere. The rate of reduction has been determined from the mass loss measured by means of the thermo-balance. The physical situation of the reduction product has been examined by microscopic observation.
    The powder of Cr2O3 in a graphite crucible as a reductant was hardly reduced, when the reduction product was solid carbide. The reduction was accelerated by continuous formation of Cr-C melt at high temperatures.
    The reduction rate of Cr3O3 by powdered graphite decreased with increasing the particle sizes of both Cr2O3 and graphite. In the case of fine powder of Cr2O3, the reduction product was formed around the graphite particle. The reduction was controlled by the diffusion of carbon or chromium in the product layer. The reduction of coarse particle of Cr2O3 proceeded topochemically and the graphite particle was not coated by the product. The reduction rate was analysed by means of the equation for rate controlled by gas diffusion through the porous product layer formed around Cr2O3.
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  • Masahiro Yamane, Kazuichi Mizoguchi, Yukio Suginohara
    1987 Volume 51 Issue 12 Pages 1152-1158
    Published: 1987
    Released: April 04, 2008
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    O1s spectra of various silicate glasses containing Ga2O3 were measured by XPS and the quantitative analysis for oxygens bonding Si-O-Si, Si-O, Si-O-Ga and Ga-O-Ga was carried out in order to study the behaviour of amphoteric oxide in silicate glasses.
    The results obtained are summarized as follows:
    (1) The quantitative analysis for O1s spectra of silicate glasses containing Ga2O3 could be performed by the same method as applied to aluminosilicate glasses. The analyzed values showed a good agreement with the calculated results which were derived from the IR spectra and viscosity of the melts combining with an electric charge balance.
    (2) O1s spectra of silicate glasses containing Ga2O3 could be measured in the composition range of molar ratio Ga2O3/MeO>1. In this composition range, a correction factor (KGa) was introduced for the evaluation of the amount of 4 coordinated Ga3+ ions so as to explain the actual physical properties with the excess amount of Ga2O3 to MeO. It was also assumed that 6 coordinated Ga3+ ions compensate the lack of electric charge balance due to the formation of Ga3+ tetrahedrons. The existing ratios of Si-O-Si, Si-O, Si-O-Ga and Ga-O-Ga calculated on the basis of the above assumption showed a good agreement with those analysed from O1s spectra measured in this study.
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  • Chikabumi Yamauchi, Toshiharu Fujisawa, Hiroshi Sakao
    1987 Volume 51 Issue 12 Pages 1159-1165
    Published: 1987
    Released: April 04, 2008
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    The present investigation was carried out to examine the chemical composition of precipitates produced during a titration of aqueous solution containing gallium sulfate with sodium hydroxide, to obtain the standard free energy of formation of Ga(III)-hydroxysalt, and to determine the pH-dependence of its solubility at 333 K.
    The results obtained are summarized as follows:
    (1) The hydrolysis proceeds via two steps. The precipitates produced in the first and second steps of hydrolysis were identified to be {Nax, (H3O)1−x}Ga3(SO4)2(OH)6, where the value of x varies with the composition of the solution, and GaOOH, respectively. These Hydrolysis reactions are represented by xNa++3Ga3++αSO42−+βHSO4+(7−x)H2O={Nax,(H3O)1−x}Ga3(SO4)2(OH)6+(5+x+β)H+, where α+β=2, and {Nax,(H3O)1−x}Ga3(SO4)2(OH)6+(x−1)H2O=3GaOOH+(x⁄2)Na2SO4+((4−x)⁄2)H2SO4.
    (2) The standard free energy of formation of {Nax, (H3O)1−x}Ga3(SO4)2(OH)6 was obtained for the values of x=0.13, 0.22, 0.38, and 0.66 at 333 K.
    (3) The pH-dependence of the solubility of {Nax, (H3O)1−x}Ga3(SO4)2(OH)6 was determined for various choices of the parameter, which can be calculated from the initial composition of solutions.
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  • Chikabumi Yamauchi, Hiroshi Sakao
    1987 Volume 51 Issue 12 Pages 1166-1173
    Published: 1987
    Released: April 04, 2008
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    The present investigation was carried out to examine the chemical composition of precipitates produced during a titration of indium sulfate containing aqueous solution with sodium hydroxide, to obtain the standard free energy of formation of In(III)-hydroxysalt, and to determine the pH-dependence of its solubility at 333 K.
    The results obtained are summarized as follows:
    (1) The hydrolysis proceeds via two steps. The precipitates produced in the first and second step hydrolyses were identified to be {Nax, (H3O)1−x}In3(SO4)2(OH)6, where the value of x varies with the composition of the solution, and In(OH)3, respectively. These hydrolysis reactions are represented by xNa++3In3++αSO42−+βHSO4+(7−x)H2O={Nax,(H3O)1−x}In3(SO4)2(OH)6+(5+x+β)H+, where α+β=2, and {Nax,(H3O)1−x}In3(SO4)2(OH)6+(2+x)H2O=3In(OH)3+(x⁄2)Na2SO4+{(4−x)⁄2}H2SO4.
    (2) The standard free energy of formation of {Nax, (H3O)1−x}In3(SO4)2(OH)6, was obtained for the x values of 0.26, 0.34, 0.64 and 0.85 at 333 K.
    (3) The pH-dependence of the solubility of {Nax, (H3O)1−x}In3(SO4)2(OH)6 was determined for various choices of the parameter, which can be calculated from the composition of solutions immediately before the beginning of the first step hydrolysis.
    Furthermore, several factors affecting the precipitation of In(III)-hydroxysalt were also studied systematically.
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  • Kazuo Kameda, Jun Tanabe
    1987 Volume 51 Issue 12 Pages 1174-1179
    Published: 1987
    Released: April 04, 2008
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    The values of emf of the galvanic cells involving zirconia solid and fused salt electrolytes have been measured in order to obtain the standard free energy of formation of In2O3 in the temperature range from 875 to 1275 K and the thermodynamic data of the liquid Sb-In system for NIn=0.10-0.90 and NIn=0.15-0.90, in the temperature ranges from 880 to 1272 and from 943 to 1200 K, respectively. The cells used were as follows:
    (This article is not displayable. Please see full text pdf.)
    The standard free energy of formation of In2O3 was determined as the following equation:
    (This article is not displayable. Please see full text pdf.)
    Activities of indium and antimony by both galvanic cell methods show negative deviations from Raoult’s law over the whole concentration range and aIn values agree well with the data measured by Niwa et al. and the others but differ from those of Terpilowski. The peak value of the heat of mixing by emf method using zirconia solid electrolytes is −3.88 kJ/mol at about NIn=0.56.
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  • Shinji Hirai, Kiyohito Tsuruta, Shigetomo Ueda
    1987 Volume 51 Issue 12 Pages 1180-1188
    Published: 1987
    Released: April 04, 2008
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    The aluminum-silicon multi-component diffusion coating, using the powder pack process, was applied to nickel and Inconel X-750 to investigate the oxidation resistance and the high-temperature corrosion resistance of the specimens.
    The results obtained are as follows:
    (1) Effects of the blending ratio of silicon in the pack material on the high-temperature oxidation resistance were examined. It was found that when 24 mass% aluminum, 6 mass% silicon, 67 mass% alumina and 3 mass% ammonium chloride were used, a coating with excellent high-temperature oxidation resistance was obtained.
    (2) The aluminum-silicon multi-component diffusion coating using pack material containing more than 6 mass% silicon, and another coating by reduction of silicon dioxide with aluminum, were tried, but neither was effective in improving the high-temperature oxidation resistance.
    (3) In an Al-Si treated layer containing 6 mass% silicon, the presence of a small amount of Si was observed at the interface between the treated layer and the basis metal before oxidation. It was also confirmed that the oxide layer consisted of silicon oxide on the surface and aluminum oxide beneath.
    (4) The specimen treated by the aluminum-silicon multi-component diffusion coating showed excellent resistance to high-temperature corrosion, which may be caused by synthetic ashes, V2O5-Na2SO4 and Na2SO4-NaCl. Particularly the specimen treated by the aluminum-silicon multi-component diffusion coating using silicon dioxide has better corrosion resistance than that treated by aluminum-silicon multi-component diffusion coating using silicon.
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  • Koji Atarashiya, Seiichi Suenaga, Ryukichi Nagasaki
    1987 Volume 51 Issue 12 Pages 1189-1193
    Published: 1987
    Released: April 04, 2008
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    The direct bonding of nickel metal to magnesia in air at 1473, 1573 and 1673 K has been studied. A block of magnesia was placed on nickel metal and was annealed at each experimental temperature for 14.4 ks to 90 ks in air.
    In the previous work, preoxidized nickel was used, but in this work, preliminary oxidation of metallic surface was not done. The role of gaseous oxygen during joining reaction was quantitatively recognized. The growth of nickelous oxide oxidized by gaseous oxygen and mutual diffusion of cations were simultaneously occured. But, nickeleous oxide was reacted with magnesia as soon as it was formed, so, pure nickelous oxide phase was not present in the reaction layers. Then, the interface layers of joining part consisted of only nickelous oxide-magnesia solid solution.
    By this method, the joining interface between nickel metal and magnesia was strengthen than that of the nickel preoxidized method in which pure nickelous oxide remained.
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  • Kazuhiko Majima, Takehiko Hirata, Keiichirou Shouji
    1987 Volume 51 Issue 12 Pages 1194-1200
    Published: 1987
    Released: April 04, 2008
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    Using two different kinds of titanium powders, some properties of P/M titanium specimens were investigated in relation to porosity. Hunter-process sponge fines showed a better compressibility than Kroll-process HDH titanium powders, but the sintered density ratio of the former became nearly the same as that of the latter due to the poorer shinkage during sintering. Both tensile strength and elongation of the sintered HDH titanium powder specimen increased nearly in proportion to the increased sintered density ratio, while in the sintered Hunter-process sponge fines specimen, there existed a flat region where both of the above mentioned static tensile properties were nearly constant independently of sintered density ratio. In the fracture surface of the sintered Hunter-process sponge fines specimen after static tensile test, there appeared non-metallic inclusions, which were identified as NaCl crystal by energy dispersive spectrum analysis.
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  • Naoji Nakamura, Hakaru Masumoto
    1987 Volume 51 Issue 12 Pages 1201-1208
    Published: 1987
    Released: April 04, 2008
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    The gage characteristics such as the strain gage factor Gf, the electrical resistivity ρ, the temperature coefficient Cf and the thermo-electromotive force relative to copper Emf were investigated for Fe-15%Cr-5-40%Co+0-7%W and Fe-15%Cr-5-40%Co+0-7%Mo alloys cold-drawn by 30-99% reduction in cross-sectional area.
    Fe-Cr-Co-W and Fe-Cr-Co-Mo alloys are scarcely varied in Gf with the reduction in area. The values decrease with increasing Co content in the former quarternary alloys as previously reported for Fe-Cr-Co ternary alloys and show a maximum at 20%Co in the latter alloys. At more than 25%Co, the values of Gf in these quarternary alloys range from 4.0 to 4.1 and is slightly larger than those of the Fe-Cr-Co ternary alloys. On the other hand, the dependence of Gf on the W or Mo content becomes smaller with increasing Co content. Compared with other gage characteristics, the dependence of ρ, Cf and Emf on W content in the Fe-Cr-Co-W alloys and that of Cf on Mo content in the Fe-Cr-Co-Mo alloys are small as is the case with Gf. From the measurement of electrical resistivity at elevated temperatures up to 1273 K and X-ray diffraction analysis, it is clear that the micro-structures of both quarternary alloys in the cold-worked state consist of an α′ phase caused by the strain-induced transformation.
    Fe-14.3%Cr-28.6%Co-4.8%W and Fe-14.7%Cr-29.4%Co-2.0%Mo alloys cold-drawn by 98% reduction in area show the following values: In the case of the former alloy, Gf=4.1, ρ=0.93 μΩ·m, Cf=7.8×10−4 K−1 and Emf=+0.6 μV·K−1; in the latter alloy, Gf=4.1, ρ=0.86 μΩ·m, Cf=4.0×10−4 K−1 and Emf=+0.3 μV·K−1. Despite a rather poor workability of cold-rolling, it is relatively easy for these alloys to be cold-drawn into fine wires. Therefore, the alloys can be used as strain gage elements in load cells and micro-strain sensors, etc.
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  • Takao Choh, Takeo Oki
    1987 Volume 51 Issue 12 Pages 1209-1215
    Published: 1987
    Released: April 04, 2008
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    The wettability between alumina ceramics and liquid aluminum was measured by the dip coverage method. The incubation period τ that preceeds wetting, was observed in all of the wetting processes. In the case of Al2O3-3%SiO2, the incubation period is short and the wetting rate decreases as compared with those of Al2O3-0.1%SiO2. The wetting process of alumina with liquid aluminum was analyzed by the same model of the nucleation rate as applied for the wetting process between SiC or graphite and liquid aluminum.
    The wettability between alumina and liquid aluminum was improved by alloying 1∼5% cerium or calcium that has greater affinity to oxygen and seems to increase the solubility of oxygen in liquid aluminum. However, lanthanum has little effect on the wettability except for the case of a higher content of 5%La and a higher silica contens of Al2O3-3%SiO2.
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  • Osamu Yanagisawa, Tetsuo Yano
    1987 Volume 51 Issue 12 Pages 1216-1222
    Published: 1987
    Released: April 04, 2008
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    In order to investigate the influence of inter-fiber spacing on proof stress in Al-Al3Ni eutectic composites, microstructure was observed in detail, and tensile and compressive 0.2% proof stresses were measured in the specimens that had been unidirectionally solidified at various rates.
    The tensile and compressive proof stresses are not coincident with each other. It may be thought that this difference is caused by residual stress. The proof stress depends on inter-fiber spacing and also cell density. The inter-fiber spacing effect is much larger than the cell density effect.
    The residual stress that has been estimated from the proof stress and rule of mixtures is also found to depend on the inter-fiber spacing. It is suggested that the dependence of proof stress on inter-fiber spacing relates to the dependence of residual stress, that has been accumulated during cooling process after solidification. Therefore, it is not adequate to understand the inter-fiber spacing dependence of proof stress in the composites in terms of Orowan’s by-pass theory, applied directly without considering the residual stress.
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