日本金属学会誌
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
63 巻, 6 号
選択された号の論文の19件中1~19を表示しています
  • 長村 光造, 石田 清仁
    1999 年 63 巻 6 号 p. 675
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
  • 安里 光裕, 星野 敏春
    1999 年 63 巻 6 号 p. 676-684
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The impurity-impurity (X-X; X=Ti-Cu, Zr-Ag) interaction energies, from 1st-neighbor to 8th-beighbor, in metals (Cu, Ni, Ag, Pd), are calculated as accurately as the lattice parameters and bulk moduli of complete metals [Materia Japan, 37 (1998), 564], based on the Korringa-Kohn-Rostoker Green’s function method for point defects [in Computational Physics as a New Frontier in Condensed Matter Research, ed. by H. Takayama et al., Physical Society of Japan, Tokyo, (1995), 105-113], using density functional theory. We use the local-spin-density approximation (LSDA) and the generalized-gradient approximation (GGA) of Perdew and Wang [in Electronic Structure of Solids ’91, ed. by P. Zieche et al., Academic Verlag, Berlin, (1991), 11-20 ]. First we review the present status of the first-principles calculations for metals; the GGA calculations correct very well the deficiencies of the LSDA for metals, i.e. the underestimation of equilibrium lattice parameters and the overestimation of bulk moduli. Secondly we show that the fundamental differences among segregation, solid solution, and ordering behavior of the binary alloys of impurity and host elements considered here, known experimentally, may be distinguished very well by use of the present impurity-impurity interaction energies. It should be noted that the observed ordering behavior of NiX (X=Mn, Fe, Co) may not be reproduced without the spin-polarization effect. The importance of magnetism in Ni-based alloys is quantitatively discussed by comparing with the calculated results for non-magnetic Pd-based alloys. Finally we show that the temperature dependence for the solid solubility limit of impurities in metals, such as Rh in Pd and Ru in Pd (PdRh and PdRu are segregated at low temperatures and become disordered at high temperatures), may be reproduced very accurately by the cluster variation method based on the present impurity-impurity interaction energies. We also found that the inclusion of the far-neighbor interaction energies is very important.
  • 大谷 博司, 宮下 正光, 石田 清仁
    1999 年 63 巻 6 号 p. 685-694
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Due to its toxicity, the development of a new Pb-free solder that would replace the traditional Pb-Sn alloys becomes the pressing need. The present study was undertaken to examine the phase equilibria in the Sn-Ag-Zn ternary system using the CALPHAD (CALculation of PHAse Diagrams) approach, which is one of the new Pb-free solder alloys. A regular solution approximation based on the sublattice model was adopted to describe the Gibbs energy for the individual phases in the binary and ternary systems. A set of thermodynamic parameters for the individual phases was achieved by combining the experimental results obtained by differential scanning calorimetry and electron probe microanalysis in the present study with literature data on phase boundaries and thermochemical properties. The optimized parameters reproduced the experimental results satisfactorily. The liquidus surface of the ternary system shows that the ternary eutectic point falls at 3.7%Ag, 0.9%Zn and 216°C. The melting point is lowered up to 193°C by an addition of Zn, and therefore the adjustment of the melting temperature might enable determination of the appropriate composition of a new Pb-free solder.
  • 石原 知, 大谷 博司, 斎藤 卓, 石田 清仁
    1999 年 63 巻 6 号 p. 695-701
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    A thermodynamic study was carried out on the Sn-In-Sb ternary alloy system. The Gibbs energy of individual phases was approximated by using the regular solution model and the two-sublattice model. The thermodynamic parameters for each phase were evaluated by using the experimental information on the phase boundaries determined by means of thermal analysis, electron probe microanalysis and other available literature data. The use of the evaluated thermodynamic parameters allowed reproducible calculations of whole phase equilibria such as liquidus, solidus, and isothermal and vertical section diagrams. The previously reported invariant reactions related with the liquid phase in the ternary system were reconsidered by the experimental data and the thermodynamic calculation.
  • 山崎 潤, 伊藤 恒有, 小路 博信, 月橋 文孝
    1999 年 63 巻 6 号 p. 702-707
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The cell model is a kind of statistical thermodynamic model for the representation of a multi component ionic liquid. This model was applied to the CaO-Ca-CaX2(X: F, Cl) system to estimate the ternary phase diagram and thermodynamic properties. The energy parameters were determined by using the binary Ca-CaX2, CaX2-CaO and Ca-CaO phase diagrams and applied to the ternary phase diagram for the CaO-Ca-CaX2 system. Activity of calcium in the CaO-Ca-CaX2 at 1473 K was calculated and compared with the observed data. The applicability of the cell model was discussed.
  • 山下 孝子, 松崎 明博, 高城 重彰, 長谷部 光弘
    1999 年 63 巻 6 号 p. 708-716
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The microstructure and precipitation behavior of cementite in Fe-0.8 mass%C-0.1 mass%B alloy were investigated to reveal the influence of B on the precipitation behavior of cementite.
    Two types of coarse cementite were observed in the specimen heated at (γ+cementite) equilibrium temperature of 1100°C. The one was Fe3(C0.33B0.67) that precipitated from the liquid phase enriched with B through the partitioning of solutions during solidification. The other was Fe3C that precipitated from the early liquid phase.
    The composition of Fe3(C0.33B0.67) remained unchanged even after the subsequent heat treatment due to its high thermodynamic stability. The Fe3(C0.33B0.67) precipitate was effective as a nucleation site of cementite in the (α+cementite) equilibrium region because Fe3(C0.33B0.67) provided a cementite nucleus with B and thermodynamically enhanced its nucleation. The cementite nucleated on the coarse Fe3(C0.33B0.67) precipitate abnormally coarsened due to its size effect.
  • 阿部 太一, 小野寺 秀博, 木村 一弘, 九島 秀昭
    1999 年 63 巻 6 号 p. 717-722
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Effects of solute elements, Mo, Mn and Cr, on the creep strength were examined by Fe-M-C(M=Mo, Mn and Cr) and Fe-C alloys in view of M-C atomic pairs. The largest strengthening effect was obtained by the addition of Mo to the Fe-C alloy, and Mn and Cr showed almost the same strengthening effects in creep tests at 773 K. Measurements of instantaneous elongation and contraction as a function of stress change revealed the existence of instantaneous plastic strain during steady state creep in all alloys. This indicates that the steady-state creep is controlled by recovery as in pure metals. For all alloys, the values of about 230 GPa were obtained as the coefficient of strain hardening by the method proposed by Ishida and McLean. The recovery rate, r, the coefficient of strain hardening, h, and the steady state creep strain rate, \dotε satisfied the Bailey-Orowan relationship, \dotε=rh, in all alloys. These results indicate that the alloying element affects mainly the recovery rate. From analysis by the model proposed by Sandström, it is concluded that M-C pair reduces the climb velocity of dislocations due to large interaction energies with dislocations. The magnitude of the reduction can be estimated from the binding energy between the M and C atoms and the diffusion coefficient of the M atom. The co-segregation of the M and C atoms on edge dislocations is predicted by thermodynamic analysis, and it is pointed out that this may result in the apparent reduction of the dislocation climb velocity even in alloys containing a very limited amount of the alloying elements.
  • 村上 秀之, 原田 広史, 斉藤 良行
    1999 年 63 巻 6 号 p. 723-732
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    This study focused on the application of Monte Carlo Simulation(MCS) in the prediction of atomic locations of alloying elements in some Ni-base single crystal superalloys. MCS based on the direct exchange of nearest neighbouring atoms was conducted by employing the Lennard-Jones pair potential, and a new algorithm optimised for vector computers was developed. For Re-containing Ni-base superalloys TMS-71 and CMSX-4, the γ and γ′ phase compositions and the site occupancy of alloying elements in the γ′ phase under equilibrium conditions were predicted by MCS, and the predictions were then compared with the estimates obtained by the Cluster Variation Method(CVM) and the experimental results obtained by atom-probe field ion microscopy(APFIM), so as to verify the applicability of MCS. It was found that the MCS estimations were generally in good agreement with both CVM predictions and APFIM results. It was also revealed that the changes in numbers of nearest neighbouring atom pairs as a function of Monte Carlo steps well describe the characteristics of alloying elements, such as partitioning and site occupancy behaviour. In addition, the drastic increase in Mo-Re nearest neighbouring pairs in TMS-71 and Cr-W pairs in CMSX-4 suggested the formation of Mo-Re and Cr-W clusters, respectively. These clusters may be a sign of precipitation of a third phase such as Topologically Close-Packed(TCP) phase. It was thus concluded that MCS is useful not only in predicting the atomic locations of alloying elements in the γ and γ′ phases, but also in discussing the possibilities of third phase precipitation and the clustering of elements, etc.
  • 足立 大樹, 長村 光造, 奥田 浩司
    1999 年 63 巻 6 号 p. 733-740
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    In order to investigate the nature of metastable phase appeared in super-high strength aluminium alloys (Mesoalite), several alloys were prepared by changing the Zn/Mg composition ratio, while Cu, Mn and Ag solute concentrations were kept constant. The effective Zn/Mg ratio dependence of the volume fraction (Vf) of metastable precipitates and the electron density difference (Δρ) between precipitate and matrix was determined from the small angle scattering intensity. The change of solute atom partition within the grains was previously reported to take place mainly for Zn and Mg during isothermal aging at 383 K. Based on the previous result, the phase diagrams of Al-Zn-Mg ternary systems were calculated by using a computer soft, ThermoCalc. In order to consider the coherent interface between matrix and metastable precipitates, the elastic strain energy was introduced into the chemical free energy. Two phases equilibria were calculated for α′+T′ and α′+η′ systems. The calculated results of Vf and Δρ could explain well the experimental data. Consequently, the metastable T′ phase is suggested to precipitate in the specimens with effective Zn/Mg ratio less than unity, while the η′ metastable phase appears in the specimen with the ratio of about 2.
  • 寒川 義裕, 桑野 範之, 沖 憲典, 伊藤 智徳
    1999 年 63 巻 6 号 p. 741-746
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    It is known that a CuAu-I (L10) type ordered structure is formed in an (In, Ga)As alloy semiconductor grown on a slightly tilted (110)InP substrate. The energy gains due to the formation of L10 in a bulk alloy, in a thick epi-layer and in a single epi-layer on a two-monolayer step, were investigated using an empirical interatomic potential calculation. It is confirmed that an L10 ordered structure is not stable in a bulk alloy. The ordered structure can exist stably in a thick epi-layer, but the energy gain due to the ordering is too small to form the ordered structure at the growth temperature. The L10 ordered structure can actually form at a two-monolayer step on the growth-surface. This indicates that the atomic arrangement near the two-monolayer step has strong effects on the stability of the ordered structure in an (In, Ga)As alloy.
  • 尾崎 由紀子, 下斗米 道夫, Pithan Christian, 岩田 修-
    1999 年 63 巻 6 号 p. 747-752
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    It is well-known that the grain boundary resistivity is several orders higher than the intragranular one for the low-loss sintered Mn-Zn ferrites containing small amount of Ca and Si. Observations by analytical transmission microscopes have revealed that Si and Ca atoms are segregated at the grain boundaries over a few nm wide. However, a correlation between the resistivity and microstrucutre remains unestablished. In this study, the scanning tunneling spectroscopy was applied for the first time to a polycrystalline Mn-Zn ferrite to study the thickness of the grain boundaries from the standpoint of electronic structure.
    Measurements have revealed that the region about 110 nm in width with small density of states is spreading across the grain boundaries. It follows that the bandgap at the region should be wide, resulting in a higher resistivity compared to the interior of the grains. The value of 110 nm, the width of high resistivity region, is much larger than the previously reported values. This suggests that Fe2+ vacancies are involved in the electronic structure. The vacancies may be generated at A or B sites in the spinel structure by the diffusion of Ca ions from the interior of grains to the grain boundary region during the cooling from the sintering temperature. This mechanism is in accordance with the model proposed by Paulus.
  • 宋 秀善, 三村 耕司, 一色 実
    1999 年 63 巻 6 号 p. 753-759
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    A purification process of iron by solvent extraction in a medium of hydrochloric acid solution has been developed. Utilizing the difference between extractable ferric chloride and non-extractable ferrous chloride into metyl isobutyl ketone (MIBK, 4-metyl-2-pentanone) in the range of 5 to 6 kmol/m3 hydrochloric acid solution even at a high iron concentration of 30 kg/m3, the purification by solvent extraction with MIBK consists of two steps; 1st step is the extraction of ferrous chloride in which extractable impurities can be separated from Fe(II), and 2nd step is the extraction of ferric chloride in which non-extractable impurities can be separated from Fe(III). Iron was produced from the purified and oxidized ferric chloride solution by evaporation to dryness, heating in air and hydrogen reduction. The produced iron sponge was then melted in H2-Ar plasma arc. The purity of iron was evaluated by residual resistivity ratio (RRRH) and glow discharge mass spectrometry (GDMS) analysis. Iron obtained by this purification process for iron with 99.9% in purity and nearly 100 in RRRH as a starting material showed RRRH of 1300 and its purity increased to about 99.999%.
  • 藤原 雅美, 大塚 正久
    1999 年 63 巻 6 号 p. 760-769
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    This study is being conducted to determine whether the indentation creep test produces results equivalent to those of the conventional unidirectional creep tests in the dislocation creep regime. A hot-hardness tester is used to obtain information on the time dependent flow, or indentation creep, of the material beneath the indenter. When a conical indenter is pressed into the (110) plane of a β-Sn single crystal, the deformation in the (001) plane just under the indenter can be regarded approximately as an in-plane strain problem. Moiré analysis of strain reveals that the plastic region in the (001) plane beneath the indenter extends while maintaining geometrical self-similarity as indentation proceeds. Observation via the etch-hillock technique also gives the same result. These findings for self-similar indentation lead to a constitutive equation from which the power law creep exponent n and activation energy for creep Q can be derived. The values Q and n vary at a temperature of 0.81Tm(Tm: melting point of tin). At low temperatures ranging from 0.60Tm to 0.81Tm, the value of Q, 44 kJ/mol, so obtained is comparable to the activation energy for pipe diffusion and the n-value is 7.5. At high temperatures of 0.81Tm∼0.92Tm, the value of Q, 107 kJ/mol, corresponds to the activation energy for lattice diffusion and the n-value is 5.4. These values indicate that there are two parallel rate-controlling processes taking place simultaneously in the creep of β-Sn. The results obtained using creep indentation are in approximate agreement with the conventional creep test results, drawn from a number of sources.
  • 山口 隆生, 山村 正明, 長坂 今夫, 大西 直之, 井久保 和則, 鈴木 弘訓
    1999 年 63 巻 6 号 p. 770-775
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    The spectral emissivity depends on the surface conditions of the materials. It is already known that the property of the spectral emissivity when an oxide film is formed on the metal surface differs from the property when there is no oxide film.
    But, it is still unknown how thick oxide film is required in order for the spectral emissivity to show the property of oxide. In other words, the relation between the thickness of the different material on the metal and the spectral emissivity is not yet obvious.
    This study is for the purpose of making clear above mentioned relationship.
    Gold, greatly different from SUS304 in the wavelength dependency of the spectral emissivity, is evaporated on the SUS304. And the spectral emissivity is measured with the layer thickness varied in many degrees. The wavelength region covers the visible one and the neighboring, 0.38-0.90 μm that is often applied in measuring color temperature. The spectral emissivity is determined by the measuring spectral reflectance at room temperature.
    Consequently, it is obvious that the spectral emissivity shows linear variations, depending on the gold layer thickness (below 0.02 μm), and that it shows asymptotic convergency to the characteristic value of gold (0.05-0.07 μm).
  • 世利 修美, 瀧川 正人
    1999 年 63 巻 6 号 p. 776-782
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    It is well-known that iron is one of the most common impurity elements observed in industrial aluminum. Iron in the aluminum forms an intermetallic compound such as FeAl3. The FeAl3 exposed on the aluminum matrix are detrimental to corrosion. A simple and effective electrochemical treatment, by which selective removal of FeAl3 can proceed, has been developed with a number of trials. It is found that FeAl3-free surface is obtained by electrochemical treatments in a 17 mass%HNO3 solution. It is explained that a selective removal by electrochemical treatment attributes to two operations; one is the activation of FeAl3 surface by H2, N2O, NO and NO2 gas evolution reactions, and the other is the cathodic reactions:
    (This article is not displayable. Please see full text pdf.)
  • 伊藤 真二, 長谷川 良佑
    1999 年 63 巻 6 号 p. 783-789
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    For a better understanding of the ion formation in a glow-discharge mass spectrometer, the values of ion beam ratio (IBR) of various ion species to singly charged ion M+ or Ar+ were compared for the both pin samples and disk samples of thirty-nine high-purity metals. The doubly charged ions such as Pr2+, Nd2+ and Sr2+ and the dimer ions such as Al2+, Ag2+ and Zn2+ showed higher IBR values beyond several %. The IBR-values of doubly charged ions showed a tendency to decrease with the values of the 2nd ionization potential and a particularly good linearity between them was found for rare earth metals. The IBR-values of argide ions (MAr+) showed the tendency to increase with the values of the 1st ionization potential, although such a relation was not found for dimer ions (M2+). These results were suggested by the analysis of reaction formulas. The difference basing on the discharge cell structure was found for the formation of M2+ and MAr+; the IBR-values of M2+ of disk samples were smaller than those of pin samples by 1-3 orders of magnitude and those of MAr+ of disk samples were one order of magnitude larger. The ratio of the yields of Ar+, Ar2+ and Ar2+ was about 100 : 10 : 1, which agreed with the ratios found in previous works. The amounts of Ar4+ and Ar5+ were below the detection limit. Between the doubly (Ar2+) and multiple charged (Arn+ : n≥3) ions, a larger drop of the IBR-value than expected form the linearity to ionization energy was found.
  • 斎藤 好弘, 宇都宮 裕, 辻 伸泰, 左海 哲夫, 洪 仁国
    1999 年 63 巻 6 号 p. 790-795
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    It is known that an ultra-fine grain size can be achieved by a special intense plastic straining processes. In this paper, the authors propose a novel intense plastic straining process named the Accumulative Roll-Bonding(ARB) for bulk materials. In the process, a strip is put on another strip neatly, at first. The two layered materials are joined together by rolling in the manner of a conventional roll-bonding process. Then, the length of rolled material is sectioned into two halves. The sectioned strips are again stacked and roll-bonded. The whole process can be repeated again and again. The achieved strain by the process is unlimited since repetition times are endless in principle. The proposed ARB process has been applied to a commercial aluminum (1100). The whole process is repeated up to 8 cycles at 473 K and well bonded strips are successfully obtained. After several cycles, ultra-fine (sub-micron) grain microstructure separated by high-angle grain boundaries is formed. The ARB process increases the ultimate tensile strength from 80 MPa to 300 MPa. It is concluded that the proposed ARB process is suitable for intense plastic forming and strengthning of bulk materials.
  • 岡本 和孝, 近藤 保夫, 金田 潤也, 吉成 明, 青野 泰久
    1999 年 63 巻 6 号 p. 796-805
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    Single crystalline austenitic stainless steels based on 316L have been manufactured in order to improve their resistance against intergranular corrosion and stress corrosion cracking. However, both the 0.2% proof strength and tensile strength of the single crystals were lower than polycrystalline 316L steel. Precipitation hardening methods were used to increase mechanical strength of the single crystals. Addition of niobium followed by solution heat treatments at 1423 K and 1523 K and an aging treatment at 1073 K were required to obtain the proper intermetallic compound precipitations. The precipitates were of Laves phase which were strongly enriched in iron, molybdenum and niobium. They were in the shape of platelets, with an average diameter of 0.3 μm and a planar density of 10 μm−2. The 0.2% proof strength and room temperature tensile strength measured for an ⟨100⟩-oriented specimen with 1.0 mass% niobium were 369 MPa and 714 MPa, respectively.
  • 松本 創, 助台 榮一, 橋本 初次郎
    1999 年 63 巻 6 号 p. 806-807
    発行日: 1999年
    公開日: 2008/04/24
    ジャーナル フリー
    It is known that ω-phase crystals in β-Ti alloys are formed by quenching, aging and stressing. It has also been predicted that athermal ω-phase crystals are formed by cooling from the negative temperature dependence of electrical resistivity in the alloys at low temperature. In order to clarify the formation of athermal ω-phase crystals formed by cooling, in-situ dark field image observations of an as-quenched Ti-15 mass%Mo alloy were carried out from room temperature to 77 K. In a specimen cooled to 77 K without electron irradiation, the formation of athermal ω-phase crystals was clearly observed, but when irradiated with electron beam the crystals were annihilated.
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