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Volume 49, Issue 1
Displaying 1-15 of 15 articles from this issue
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Naotsugu Inakazu, Hisashi Yamamoto, Ryuichi Matsui1985 Volume 49 Issue 1 Pages 1-8
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe influence of the deformation band and the initial grain boundary on the recrystallization behavior of drawn aluminium single- and bi-crystals was investigated.
The results are as follows:
The preferred orientation of deformation band almost consist of the ⟨100⟩ axial components, while the matrix is composed of the ⟨111⟩ axial components, that are stable during drawing.
As for the recrystallization, the deformation band accelerates the rotation relationship from the other orientation to the ⟨100⟩ component, which results in the development of the cube texture.
The above-mentioned relationship corresponds to the orientation relation of a recrystallized grain by keeping order at intervals of 5 to 37 atoms on the {111} plane of the matrix or the {100} plane of the deformation band.
From the observation of lower recrystallization rate and finer recrystallized grain in bi-crystals than those in single crystals, it is considered that the initial grain boundary absorbs dislocations and leads to the “in situ” recrystallization.View full abstractDownload PDF (2035K) -
Yukio Inokuti, Shigeko Sujita, Yo Ito1985 Volume 49 Issue 1 Pages 9-14
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFormation of MnS in the vicinity of the steel surface during annealing in N2 gas after final annealing and subsequent coating treatments of grain oriented silicon steel containing MnS as an inhibiter was investigated. The morphology of MnS was observed by a transmission electron microscope with extraction replicas, and the composition of MnS was determined by means of energy dispersive X-ray analysis, electron probe microanalysis and Auger electron spectroscopy. The results are as follows.
(1) MnS is formed preferentially in the vicinity of the steel surface after the annealing in N2 for duration more than 12 ks in the temperature range between 1073 and 1173 K. MnS has the plate-like or rod-like morphologies and is 0.1-5 μm in size.
(2) Formation of MnS decreases drastically in 20 μm depth from the steel surface, and no precipitates are observed in the central area.
(3) MnS does not contain impurity elements in precipitates themselves.
(4) The orientation relationship between MnS and silicon steel matrix is considered to satisfy relations of (1\bar11)MnS\varparallel(110)α and [1\bar1\bar2]MnS\varparallel[001]α or (012)MnS\varparallel(110)α and [100]MnS\varparallel[001]α.View full abstractDownload PDF (1589K) -
Yukio Inokuti, Shigeko Sujita, Yo Ito1985 Volume 49 Issue 1 Pages 15-19
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFormation of MnSe in the vicinity of the steel surface during annealing in N2 gas after final annealing and subsequent coating treatments of low iron loss grain oriented silicon steel containing MnSe, Sb and Mo as inhibiters was investigated. The morphology of MnSe was observed by a transmission electron microscope with extraction replicas, and the composition of MnSe was determined by means of energy dispersive X-ray analysis, electron probe microanalysis and Auger electron spectroscopy. The results are as follows.
(1) MnSe is formed preferentially in the vicinity of the steel surface during the annealing in N2 for the duration more than 600 s in the temperature range between 1173 and 1223 K.
(2) MnSe with thin plate-like morphology is formed parallel to the sheet surface.
(3) MnSe contains Mn, Se and S, or Ti in precipitates themselves.
(4) The orientation relationship between MnSe and silicon steel matrix is considered to satisfy the relation of (012)MnSe\varparallel(110)α and [100]MnSe\varparallel[001]α.View full abstractDownload PDF (1406K) -
Hidekazu Sueyoshi, Katsuro Suenaga, Ryohei Tanaka1985 Volume 49 Issue 1 Pages 20-25
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTransformation behavior of structural steel S50C during isothermal treatment was compared with that of hypo-eutectoid alloy steels containing silicon, nickel and cobalt, focusing on a graphite precipitation, and a nucleation mechanism of graphite that precipitated from austenite was discussed according to the classical nucleation theory and the theory of reaction kinetics.
It was suggested that the machanism of graphite nucleation in the steels containing silicon, nickel and cobalt consists of a series of processes such as clustering of solute carbon atoms, the diffusion of iron atoms and the formation of critical nuclei. The clustering of solute carbon atoms is stimulated by the addition of silicon, nickel and cobalt, because the activity of carbon is raised by the existence of these atoms.
The rate of graphite nucleation mainly depends on the free energy of formation of critical nuclei just below the eutectoid temperature of the iron-graphite system, and on the diffusion rate of iron atoms at lower temperatures. The phenomenon that the curve for graphite precipitation in TTT relationship results in a “C” curve was successfully explained by this temperature dependence of graphite nucleation rate.View full abstractDownload PDF (1621K) -
Ryohei Satoh, Muneo Ohshima, Katsuhiro Arakawa, Kazuo Hirota1985 Volume 49 Issue 1 Pages 26-33
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn investigation has been made of the structure and tensile properties of the Pb-Sn solders which are important micro-soldering and bonding materials used in the fabrication of semiconductors ICs (Integrated Circuit) and LSIs (Large Scale Intergrated circuit).
During the soldering operation the Pb-Sn solders are undergoing a melting and solidifying process, and are in the so-called casting state; they exhibit a structure with significant segregation in the composition. This structure is thought to have a large influence on the reliability of the soldered joint.
To evaluate the mechanical properties of the micro-soldered joint, cast solder samples (Pb/Sn(in mass%)=100, 99/1, 97/3, 95/5, 93/7, 90/10, 85/15 and 37/63 (eutectic composition)) were solidified and formed at the conventional cooling rate (about 1 K/s). The micro-structure and tensile properties of these samples were investigated. The results are summarized below.
(1) The cast solders exhibit a dendrite structure with the segregation of composition. They show very little elongation as compared with rolled materials.
(2) For Pb-rich solder alloys, tensile deformation occurs primarily within the grains, and virtually no grain boundary sliding of the type seen in rolled materials is observed.
(3) Eutectic phase crystals, caused by the concentration of Sn into the grain boundary and between the dendrites (i.e., within the grains), are observed in the cast structure as a result of segregation in composition. In Pb-rich solders, this eutectic phase suppresses the rotation of the crystalline grains and the grain boundary sliding, and thereby causes the reduction of tensile elongation.View full abstractDownload PDF (2769K) -
Hideo Tanabe, Masahiro Kitada1985 Volume 49 Issue 1 Pages 34-39
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMagnetic and magnetoresistive properties of as-sputtered and annealed permalloy thin films have been investigated. The composition of a permalloy target used is Ni-19 mass%Fe with zero-magnetostriction. The annealing is carried out both in hydrogen and in a vacuum. The properties of electron beam deposited permalloy thin films are also investigated, comparing with sputtered films. Magnetic properties (coercivity: Hc, magnetic anisotropy field: Hk) and average electrical resistivity (ρa) of as-sputtered films increase with decreasing base pressure before the introduction of the Ar sputtering gas. Saturation magnetization (Is) and magnetoresistivity change (Δρ) decrease with decreasing base pressure. Therefore, the magnetoresistivity ratio (Δρ⁄ρa) decreases. Moreover, the Is and Δρ of as-sputtered films are lower than those of EB deposited films and the ρa is higher, while the Hc and Hk are equivalent. The magnetic and magnetoresistive properties of sputtered films scarcely change by annealing in a vacuum. On the other hand, the Is and Δρ of the specimens increase and ρa decreases with annealing in hydrogen. Consequently, Δρ/ρa increases, but there is little change in the properties of EB deposited films with hydrogen annealing. Auger analysis indicates that the concentration of oxygen in sputtered films is larger than that of EB deposited one and decreases with hydrogen annealing. This result suggests that the increase of Is and Δρ and the decrease of ρa are caused by eliminating oxygen from the sputtered films.View full abstractDownload PDF (1278K) -
Kozo Nakazawa, Yoshikuni Kawabe1985 Volume 49 Issue 1 Pages 40-45
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe delayed fracture of an ultrahigh strength maraging steel in hydrogen gas was studied with notch tensile specimens at room temperature. It was shown that the delayed fracture behaviors in hydrogen gas were affected significantly by the environmental conditions during loading. When the specimens were loaded in hydrogen gas, the delayed fracture strength was extremely low. When they were loaded in vacuum and then exposed to hydrogen gas environment, the delayed fracture strength was considerably higher than that of the specimens loaded in hydrogen gas. This difference in the degree of embrittlement between them was able to be explained by the strong dependence of the hydrogen absorption by the fresh surface that was produced by plastic deformation on the loading conditions, that is, the delayed fracture was probably controlled by the hydrogen absorption. The delayed fracture strength evaluated by loading in hydrogen gas was approximately equal to the notch tensile strength obtained by the slow strain rate technique at both 6.67 kPa and 66.7 kPa hydrogen gas pressures. These strength values were estimated to be the lower critical stress below which the fracture of the notch tensile specimens did not occur for the hydrogen gas environment used in this study. This lower critical stress was discussed in view of the start of the plastic deformation at the notch of the specimens.View full abstractDownload PDF (1148K) -
Shigeru Ando, Shimoo Toshio, Hiroshi Kimura1985 Volume 49 Issue 1 Pages 45-50
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe carbon deposition on iron has been studied by means of metallography and thermogravimetry, in order to investigate the carbon depositing behavior and the rate-determining step of the reacion. Two types of carbon, laminar carbon and filamentous carbon, are observed to deposit on iron. The deposition of laminar carbon is predominant through the reaction to form a thick lamina on the entire surface of iron. Filamentous carbon does not deposit on iron but on laminar carbon, and the amount of the deposit is much less than that of laminar carbon. X-ray diffraction shows that iron and cementite are included in laminar carbon. This may be caused by the fact that the iron substrate is attacked by formation and decomposition of cementite on the surface and at the grain boundaries during carbon deposition and that iron and cementite are spalled away into the deposit.
The deposition rate of laminar carbon is controlled by the following reactions on substrate-carbon interface according to gas composition;
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\ oindentand in the intermediate range both these reactions, where O∗ is an adsorbed oxygen atom.View full abstractDownload PDF (1740K) -
Chikabumi Yamauchi, Hiroshi Sakao1985 Volume 49 Issue 1 Pages 51-58
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe present investigation was undertaken to examine the chemical composition of precipitates produced during a titration of aluminium sulfate with sodium hydroxide and to determine the pH-dependence of its solubility at 333 K.
The results are summarized as follows:
(1) The hydrolysis of aluminium sulfate proceeds via two steps. In the case where the initial concentration of Al2(SO4)3 was less than 0.05 mol·dm−3, the precipitates produced in the first and second steps of hydrolysis were identified to be Al7(SO4)2(OH)17·xH2O and Al(OH)3, respectively. These hydrolysis reactions are represented by 7Al3++αSO42−+βHSO4−+17H2O=Al7(SO4)2(OH)17+(17+β)H+, where α+β=2 and Al7(SO4)2(OH)17+4H2O=7Al(OH)3+2H2SO4.
(2) For the equilibrium constant, K, of the first step of hydrolysis at 333 K, logK was calculated to be −36.60±1.32, from which −8474.4±10.2 kJ·mol−1 was obtained as the standard free energy of formation of Al7(SO4)2(OH)17 at this temperature.
(3) The pH-dependence of the solubility of Al7(SO4)2(OH)17 was determined for various choices of the parameter ε, which can be calculated from the initial composition of solutions (see Fig. 4).
(4) A method was proposed which enabled us to calculate the activity coefficient of H+, HSO4− and SO42− ions as a function of the ionic strength for the parameter of H2SO4 concentration.View full abstractDownload PDF (1021K) -
Kojiro F. Kobayashi, Masa-ichi Kumikawa, Paul Hideo Shingu1985 Volume 49 Issue 1 Pages 59-63
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAl-Si alloys with compositions in the range from 0 at% to 30 at%Si were rapidly solidified from the melt by the single roller method. The lattice parameter of aluminum decreased with increasing silicon content up to about 16 at%, indicating the extended solid solubility, but increased again for much higher silicon content. Examination by a scanning electron microscope (SEM) revealed that the eutectic structure appeared at about 25 at%Si, whereas the equilibrium eutectic composition was 12 at%Si.
The exothermal heat of the ribbons measured by differential scanning calorimetry (DSC) was as large as about 150 kJ/kg for 16-30 at%Si samples. It was mainly caused by the decomposition of supersaturated solid solution for samples with relatively low silicon contents and by the reduction of surface area of finely branched eutectic silicon during coarsening for samples with higher silicon contents. The measurement of electrical resistivity (standard four-probe technique) showed that the solid solution was stable up to about 450 K at the continuous heating of 0.33 K/s.
Spheroidization and subsequent dispersion of the fibrous silicon phase took place at far lower temperatures and shorter annealing times in comparison with the conventionally solidified sample. The reason for such an enhancement of the structural change can be attributed to the highly unstable fine net work structure of the silicon phase and the high supersaturation of silicon in the aluminum matrix.View full abstractDownload PDF (1451K) -
Tetsuyuki Ikeda, Seiki Nishi, Takashi Yagi, Masahiko Shimazaki1985 Volume 49 Issue 1 Pages 64-71
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn Al-20%Sn alloy with a wide range of solidification temperature was cast from a casting temperature of 1073 K in a moving metal mold with spray cooling at mold moving speeds of 1.4 to 8.1×10−3 m/s. The dimension of ingots was 90 to 104 mm wide, 145 mm high and 10 to 12 mm thick. The relation between solidified structure and condition for casting was examined for these ingots, and also these solidification processes were computed from cooling curves. The gravity segregation was able to be prevented at mold moving speeds of 2.9×10−3 m/s and above 8.1×10−3 m/s. These cast structures consisted of uniform equiaxed crystal grains. The crystal grains were rectangular cells or undeveloped dendritic cells 25 to 30 μm in size. At a mold moving speed of 2.9×10−3 m/s the solidification process proceeded unidirectionally from the bottom of the ingot to the upper part, and the tin phase was dispersed uniformly with the shape such as a green caterpillar or a sphere by two-step solidification. On the one hand, at a mold moving speed of 8.5×10−3 m/s the solidification process proceeded from the sides of a mold towards the center, and the tin phase was distributed with the flaky shape at cell boundaries, which formed the morphology of imperfect network.View full abstractDownload PDF (1863K) -
Isamu Yamauchi, Itsuo Ohnaka, Satoru Kawamoto, Tatsuichi Fukusako1985 Volume 49 Issue 1 Pages 72-77
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe rotating-water-atomization process developed by the authors was applied to produce rapidly solidified Al-Si alloy powders containing Si between 7.1% and 23.7%. The particle shape was not spherical but tear-drop like. The size distribution and the mean particle diameter were independent of Si content. The structure of as-atomized particle was composed of finely dispersed Al and/or Si primary crystals in the eutectic matrix, and primary Si was hardly observed for a Si content less than 16.3%Si. The number of primary Si increased with increasing Si content. The variation with Si content of the lattice parameter of as-atomized particles showed a minimum at 16.3%Si. Two exothermic reactions were observed at about 500 K and 650 K, respectively, by DSC thermal analysis. Heat generated at about 500 K was maximum at 16.3%Si and it was consistent with the lattice parameter variation. Coarsening of Si particles at 723 K was very fast at the initial stage of annealing, and afterwards it was proportional to t1⁄3.View full abstractDownload PDF (2119K) -
Hideharu Fukunaga, Koichi Goda1985 Volume 49 Issue 1 Pages 78-83
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt may be predicted that a thin solidified layer occurs on the surface of a fiber when the fiber reinforced metal is fabricated in a certain condition by the liquid process. The present paper deals with the demonstration of appearance of the layer and its effect on the tensile strength of composites.
A model was proposed on the formation of the solidified layer, and the theoretical prediction of the permeability coefficient of molten metal to fiber preforms was derived from the model in connection with the production variables. A series of experimentals to measure the permeability in various fabricating conditions showed a good consistency with the theoretical one, so the model was verified.
Other experiments were carried out to investigate the role of the layer. The tensile strength of specimens is always higher for the composites fabricated in the condition with the solidified layer than without the layer. Moreover, a lot of the reaction traces between fiber and matrix metal were observed on the fiber extracted from the composites without the solidified layer. These results show that the solidified layer acts as a protective film between the fiber and molten metal.View full abstractDownload PDF (1540K) -
Takafumi Nakayama, Hakaru Masumoto, Michio Kikuchi1985 Volume 49 Issue 1 Pages 84-88
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe thermal expansion, magnetic property, hardness and workability were investigated for Mn-22%Ge based ternary ε phase alloys containing noble metals in the groups VII A, VIII and I B in the periodic table. In thermal expansion curves of the ternary alloys there appear minima corresponding to the Néel point of the ε phase, showing the Invar characteristics below this temperature. The thermal expansion coefficients of the ternary alloys in the vicinity of room temperature show zero or a negative value. The spontaneous volume magnetostriction of Mn-22%Ge-0.9%Ir, 1.7%Ag and 0.9%Au alloys at 77 K is about 1.3×10−2, and it is hardly affected by the kind of additional element and nearly equal to that of Mn-22%Ge binary alloy and Invar-type Fe-Ni or Fe-Pt alloys. The magnetization of the ternary alloys shows almost the same temperature dependence as that of Mn-22%Ge binary alloy which shows a parasitic ferromagnetism. The magnetization at T⁄TN=0.65 decreases with increase of the additional elements except for Ag. The Néel point of the ε phase is scarcely affected by the third elements except for Ir, Pt and Re.
The Vickers hardness of almost all ternary alloys containing the noble metals less than 2 percent shows a value lower than that of Mn-Ge alloys, and they are superior in machinabilities such as cutting and forging to the binary alloys.View full abstractDownload PDF (655K) -
Kiyoshi Aoki, Tsuyoshi Masumoto1985 Volume 49 Issue 1 Pages 89-96
Published: 1985
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStructural change and crystallization process of as-quenched or hydrogenated amorphous Zr-Ni alloys during heating in H2 or Ar atmosphere were investigated by X-ray diffraction and differential thermal analysis (DTA). In hydrogen atmosphere, amorphous Zr-Ni alloys (Zr=37, 50 and 66.7 at%) absorb hydrogen in the amorphous state at relatively low temperatures, and decompose into a hydrogen absorbed amorphous phase+ZrH2 at intermediate temperatures and finally crystallize to Zr2Ni7+ZrH2 at elevated temperatures. The formation temperature of ZrH2, Tz in the amorphous phase increases with decreasing Zr content in the alloy. The hydrogenated nickel rich amorphous alloy (Zr=37 at%) desorbs hydrogen thoroughly below Tx and no ZrH2 phase is formed during its heating. The crystallization processes of the other hydrogenated amorphous alloys (Zr=50 and 66.7 at%) in Ar atmosphere are as follows: hydrogen absorbed amorphous phase Am(H)→Am′(H)+ZrH2→Zr7Ni10+ZrH2→ZrNi+H2 (or ZrNi+ZrH2+H2).View full abstractDownload PDF (1128K)
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