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Volume 41, Issue 6
Displaying 1-18 of 18 articles from this issue
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Kazuyoshi Sekine, Osamu Yoshimura1977 Volume 41 Issue 6 Pages 535-541
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe recent papers of the authors proposed a new theory to uniquely predict the final orientation of deformation textures in polycrystalline metals. In the proposed theory, rotation vectors and skew-symmetric parts of stress tensor, which were neglected in the classical theory of plasticity, are needed for the description of the crystal rotation behavior of grains and a yield function which determines the onset of rotations is defined in nine-dimensional stress space.
In this paper, it is shown that the proposed form with respect to the yield function of rotations is also established by generalizing the Mises and Hill yield criteria of the classical theory of plasticity, and the proposed yield function is applied to simulate the rolling texture and surface rolling texture formations in fcc metals deformed by {111}⟨110⟩ multiple slip, using the extended maximum work and the extended minimum shear procedures concerning the crystal plasticity. The simulated rolling texture of fcc metals is described as a continuous distribution of orientation between near {123}⟨211⟩ and {4, 4, 11}⟨11, 11, 8⟩ and is essentially similar to the pure metal type texture. And the simulated surface rolling texture consists mainly of the {001}⟨110⟩ orientation with minor components of {111}⟨110⟩.View full abstractDownload PDF (624K) -
Takeshi Sadahiro, Toshiaki Cho, Susumu Yamaya1977 Volume 41 Issue 6 Pages 542-545
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of the reaction temperature and gas composition on the deposition rate and structure of TiN were investigated.
The results obtained are as follows.
(1) The deposition of TiN increased linearly with deposition time, gas flow rate and TiCl4 content.
(2) TiN deposition increased linearly as a function of PH2·PN21⁄2. The deposition was controlled by the following two reactions: TiCl4+H2=TiCl2+2HCl, TiCl2+H2+1⁄2N2=TiN+2HCl.
(3) TiN showed a wide range of nonstoichiometry. The TiN obtained near a N2/TiCl4 mole ratio of 30 in the gas phase was stoichiometric but for the mole ratio above that value it was nitrogen excess. The (110) plane was developed in parallel with the surface of the cemented carbide substrate.View full abstractDownload PDF (353K) -
Atsumi Ohno, Tetsuichi Motegi, Kenji Ishibashi1977 Volume 41 Issue 6 Pages 545-551
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of the rotation of mold and electromagnetic stirring on the formation of equiaxed zone of 99.7% aluminum ingots were studied using a graphite mold and a shell mold.
It was found that the rotation of mold must be stopped during solidification to get an equiaxed zone of ingots since continuous rotation of mold produced an ingots of entirely columnar structure. Equiaxed crystals were most violently formed when the rotation of mold was stopped in the initial stage of solidification. In the case of electromagnetic stirring of molten metal in the mold, the separation of equiaxed crystals from the mold wall was most effective in the initial stage of solidification before the formation of stable solid skin.
It was concluded that the pouring temperature must be adequate to avoid the formation of stable solid skin on the upper region of the mold during the electromagnetic stirring treatment.View full abstractDownload PDF (928K) -
Osamu Michikami, Shoichi Yamamoto1977 Volume 41 Issue 6 Pages 551-558
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe solid solution of silver containing 0.42∼2.09 at%Ga was cold-worked and internally oxidized at temperatures between 500 and 650°C in still air for viarious times. The effects of oxidation temperature, time and solute content on the growth of the internally oxidized layer were investigated. The product of the solubility N0(s) and the diffusivity D0 of oxygen, and the activation energy for N0(s)D0 were calculated by Wagner’s equation.
The results were summarized as follows.
(1) The relation between the depth of the oxidation zone and the oxidation time can be expressed by a parabolic law. It was concluded that internal oxidation was governed by the diffusion of oxygen through the internally oxidized layer.
(2) The activation energy for the product N0(s)D0 determined from the internal oxidation of the cold-worked Ag-0.42 at%Ga alloy below 550°C and above 600°C was 19.8±0.5 kcal/mol and 22.4±0.4 kcal/mol, respectively. The activation energy for internal oxidation of alloys except 0.42 at%Ga alloy was 23.3∼25.0 kcal/mol and slightly increased with increasing Ga content.
(3) The product N0(s)D0 of oxygen in pure silver obtained by extrapolating Ga content to NGa(0)=0 was given by (13.5±0.4)×10−5exp[(−23400±600)⁄RT]. This value is in agreement with the product of the values of N0(s) and D0 determined individually by Eichenauer and Müller.View full abstractDownload PDF (732K) -
Hisashi Suzuki, Koji Hayashi, Osamu Terada1977 Volume 41 Issue 6 Pages 559-563
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt has been previously reported by the present authors that the transverse-rupture strength of WC-Co cemented carbide at room temperature is quantitatively understood from the viewpoint of microstructural defects acting as fracture sources. Thus, the strength of WC-Ni cemented carbide was examined in relation to the defect as above, in order to make clear the strength of this alloy in comparison with that of WC-Co alloy. The WC-10%Ni medium carbon alloys with various carbide grain sizes were vacuum-sintered and used as specimens.
The results obtained were as follows: (1) It was confirmed that the strength of WC-10%Ni alloy was controlled by the microstructural defect in the same way as in WC-Co alloy. However, in this case, pores were only observed as the defect. (2) Considering the strength (σ0) of the sound matrix around defects, σ0 of WC-10%Ni alloy was lower than that of WC-10%Co alloy. The difference in σ0 between the two alloys, however, became smaller with decreasing carbide grain size, and σ0 of both alloys nearly accorded when the grain size approached the value of 1.0∼1.2 μ. (3) The hardness of WC-10%Ni alloy was lower than that of WC-10%Co alloy, and the similar tendency was also observed in respect of carbide grain size. (4) The more excellent mechanical properties of WC-Co alloy were assumed to be due to the strain-induced transformation of its binder phase which is peculiar to this alloy.View full abstractDownload PDF (514K) -
Bakk Chang, Satoru Yamamoto, Yutaka Kawano, Ryohei Ozaki1977 Volume 41 Issue 6 Pages 564-570
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe present work is concerned with the nodular graphite formation caused solely by the addition of the so-called deterious elements such as Bi and Pb.
The results obtained are as follows:
(1) It was confirmed that nodular graphites were certainly formed in cast iron only by the addition of Bi or Pb above its boiling point.
(2) During holding the melt, graphite nodules decreased in number by the loss of the gas bubbles of Bi and Pb due to the floatation up to the surface.
(3) The concentric structure of nodular graphite was revealed by scanning electron microscopic observation.
(4) Both the residual Bi and Pb in nodular graphite are distributed along the (0001) basal planes of graphite.
These results in the present work were compared with those by other investigators, and it was clarified that the effects of Bi and Pb on nodular graphite formation could be explained not by other theories but by gas-bubble theory proposed by the present authors.View full abstractDownload PDF (960K) -
1977 Volume 41 Issue 6 Pages 570
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPlease see pdf. Wrong:log PMg=−7550/T-1.41 log T+9.91 (atm) (1) Right:log PMg=−7550/T-1.41 log T+12.79 (Torr) (1)View full abstractDownload PDF (73K) -
The Nodular Graphite Formation in Cast Iron by Suspension of Bubbles of Gases such as N2, Ar and CO2Bakk Chang, Satoru Yamamoto, Yutaka Kawano, Ryohei Ozaki1977 Volume 41 Issue 6 Pages 571-578
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the present work, some trials were carried out to confirm the ability of the nodular graphite formation by suspension of bubbles of gases such as N2, Ar and CO2 inside the molten cast iron.
The main results obtained are summarized as follows:
(1) Graphite nodules were obtained by the direct injection of gases such as N2, Ar and CO2 into the melts through the extra fine porous plugs.
(2) Graphite nodules were also obtained by the precipitation of nitrogen as gas bubbles from super-saturated molten cast irons.
(3) Gas cavities or hollow graphite nodules were often observed which seem to be formed by incomplete filling up of gas bubbles with graphite.
These results and some phenomena connecting with them were discussed on the basis of the gas-bubble theory.View full abstractDownload PDF (1175K) -
Akihiko Nagata, Hiroshi Hirayama, K\={o}shichi Noto, Osamu Izumi1977 Volume 41 Issue 6 Pages 578-583
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe superconducting transition temperature and the critical current density of a splat-quenched Cu-0.4 at%Nb alloy were measured after age-treatments and the structure of some samples was observed by transmission electron microscopy. The results obtained are summarised as follows.
(1) In the samples as splat-quenched and aged at a relatively low temperature, the size of the precipitates (Nb particles) is small (<0.05 μm) and the superconductivity does not appear above 4.2 K. But after aging at 700°C for 4 hr, large precipitates (0.1∼0.2 μm) are observed and then the superconductivity appears above 4.2 K.
(2) The highest TC observed is 5.8 K when the sample is aged at 900°C for 4 hr, and the highest JC is about 95 A/cm2 when it is aged at 800°C for 4∼8 hr.
(3) The transition temperature TC and the critical current density JC of this sample show strong dependences on the size and the spacing of the Nb-precipitates. Therefore, it is considered that the superconductivity in this alloy is due to the proximity effect of Nb particles which precipitate on the grain boundaries.View full abstractDownload PDF (583K) -
Hiroshi Fujiwara, Kazuhiro Hara, Kunito Okamoto, Takashi Hashimoto1977 Volume 41 Issue 6 Pages 584-589
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe geometrical and crystallographic analyses have been made on the oblique incidence Fe films, evaporated at the rates of 500 Å/min, 2500 Å/min and 1 μm/min. For all the films, the incidence angle and the substrate temperature were 45° and 200°C, respectively. Electron microscopic observation on the surface and the cross-section of the film, and analysis of pole figures plotted by the use of the X-ray Schulz method have revealed the following results.
(1) For all the films, the columnar structure was clearly seen in the cross-section of the film and the inclination angle of the column axis is 30° off from the film normal toward the direction of vapor beam. No distinctive dependence of the shape and width of the column on the evaporation rate has been found.
(2) Four kinds of geometrical configurations, which depend on the evaporation rate, were detected in the top shape of columns appearing on the film surface. Also, the film have the preferred orientation, i.e. the texture which strongly depends on the evaporation rate.
(3) On the assumption that a crystallite in the film has a rhombic dodecahedral habit, the appearance of each top shape and the crystallographic correspondence between the respective shapes and textures may be understood well.
The above mentioned results suggest that there might be a correlation between the formation mechanisms of the columnar structure and of the texture, and the growth direction of the column might be determined by a mechanism related to the movement of atoms which are adsorbed successively on the top of the column.View full abstractDownload PDF (830K) -
Isamu Yamauchi, Koji Kishida, Itsuo Ohnaka, Tatsuichi Fukusako1977 Volume 41 Issue 6 Pages 589-595
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSome factors affecting the apparent thickness of the partially solidified layer on the original metal rod surface in the dip-forming process of the skin freezing process were investigated experimentally by dipping tests using 99.99%Al, Al-0.5%Cu, Al-2%Cu and Al-4.5%Cu alloy. Solid fraction was calculated by Scheil’s equation from the temperature distribution measured in the partially solidified region. The shear stress acting on the interface during the raise of the metal rod was estimated under some simple assumptions. The calculation of the solidification profile in this experiment was done by the finite difference method. The results obtained were as follows:
(1) In pure Al and Al-Cu alloys without Ti, the apparent solid layer was columnar structure and corresponding to the position of 0∼30% solid fraction in Al-2%Cu alloy and 0∼15% in Al-4.5%Cu alloy.
(2) The shear stress acting on the partially solidified region in raising the rod from the bath was much lower than the apparent strength of the region. Therefore the apparent thickness was decided by such a low solid fraction region.
(3) Interface heat conductances h between the metall rod and the solid layer were obtained by comparing the experimental and calculated values. In the concentrated heat flow condition, h decreased with Cu content and increased with dipping time.
(4) The apparent thickness was thicker with Cu content in the short dipping time and then this relation was reversed after a prolonged dipping time. This was caused by the difference in the partially solidified temperature range and in the thermal condition due to Cu content.View full abstractDownload PDF (633K) -
Tadao Ishihara, Shinobu Matsushima, Shigeo Ohashi, Yoshihiko Shimizu1977 Volume 41 Issue 6 Pages 596-601
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of environmental factors such as testing temperature, pH and chloride concentration of the testing solution, and the applied stress level of the specimen on the initiation and propagation times of stress corrosion cracking of Type 304 stainless steel in high temperature water were studied.
Stress corrosion tests were carried out in an autoclave specially designed to measure the elongation of specimens, loaded with uni-axial tensile stress and exposed to chloride-containing water in the temperature range of 150 to 325°C.
The results of tests showed that each of the environmental factors mentioned above had a significant effects on the time to initiate cracks. Namely, the initiation time of cracking increased with an increase in pH value, and with a decrease in chloride concentration and applied stress level. The most susceptible temperature was 225°C. Furthermore, it became evident that the cracking process after crack initiation proceeded with a rapid propagation; hence the induction period for crack initiation indicated a large fraction of the fracture time.
On the basis of the results obtained above, it was concluded that the environmental factors have a dominating effect on crack initiation rather than crack propagation.View full abstractDownload PDF (564K) -
Akihiko Tanaka1977 Volume 41 Issue 6 Pages 601-607
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe activities of manganese in Mn-C, Mn-Si, Mn-Si-Csat. and Mn-Fe-Si-Csat. solutions at 1400°C have been determined. The transportation method was applied to the vapor pressure measurement. The results obtained are as follows:
(1) The values of the vapor pressure of pure manganese at 1350 and 1400°C in this work agreed approximately with those obtained by previous measurements in the literature.
(2) The activities of manganese in the Mn-C solutions, as referred to pure manganese were determined from the vapor pressure data. It was found that the activities of manganese in these solutions show a positive deviation from ideality at less than 0.17 of NC and deviate negatively above this value.
(3) The activities of manganese in the Mn-Si solutions were determined in the same way. The activities of silicon as referred to pure silicon in the liquid state in the Mn-Si solutions were calculated from the activities of manganese obtained by means of the Gibbs-D\v{u}hem integration and conversion of the reference state. These activities showed a remarkable negative deviation from ideality. Some thermodynamic quantities at 1500°C were calculated on the assumption that the Mn-Si solutions are considered to be a regular solution.
(4) The activities of manganese obtained in Mn-Si-Csat. and Mn-Fe-Si-Csat. solutions were expressed in the form of an activity curve and isoactivity curves, respectively.View full abstractDownload PDF (557K) -
Nobuya Shinozaki, Hiroshi \={O}kusu, Kazuichi Mizoguchi, Yukio Suginoh ...1977 Volume 41 Issue 6 Pages 607-612
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe electrical conductivities of Na2O-SiO2-NaF melts and the infrared absorption spectra of its glasses were measured in order to elucidate the effect of fluorides on the structure of silicate melts.
The results obtained are as follows: The electrical conductivities increased with increasing NaF when the value of Na2O/SiO2 was constant, but they decreased with increasing NaF when SiO2 mol% was constant. The wave number of absorption peak due to ν3-vibration of silicate anion did not shift at all with increasing NaF.
From these results it is considered that NaF does not act on silicate as a “modifier” but as a “dilution” and exists in melts as free Na+ and F− ions, and F− ions contribute to the electrical conductivities with Na+ ions and those contributions are about 1/8 as much as Na+ ions.View full abstractDownload PDF (483K) -
Jirô Watanabé, Shigeo Sugawara1977 Volume 41 Issue 6 Pages 612-619
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDislocation etch pits formed by Young’s etching on {111} surfaces of as-grown Cu and Cu-Al dilute alloy crystals have been observed. Three kinds of triangular pits, dark, light and their mixture, are observed on Cu crystals by a low-magnification optical microscope. The forms of these pits are investigated in detail with an electron microscope. The dark pits show a sharp pointed triangular pyramid with sides inclined more than 7°, while the light pits show three varieties of shallower triangular pyramid. Three kinds of pits consisting of the dark and light parts are also obtained. Etch pit morphology observed on 0.1 at%Al alloy crystals is similar to that on Cu crystals. However, dislocation etch pits produced on 1∼2.5 at%Al alloy crystals are mostly the dark or the light type. Moreover, with the addition of Al, the etch pits become rounded and its size and slope become smaller. The effect of Al is discussed on the basis of the two-dimensional nucleation theory of dislocation etch.View full abstractDownload PDF (1639K) -
Takumi Sone, Kyuhiko Yamanaka1977 Volume 41 Issue 6 Pages 620-625
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCarbon steels ion-nitrided under various conditions were examined with respect to the microstructure, hardness, phase and thickness of the compound layer, and the depth of the diffusion layer. Furthermore, the wear resistance of ion-nitrided carbon steels was investigated under the unlubricated condition by means of an Ogoshi rapid wear testing machine. The following results were obtained.
(1) The amounts of the ε-Fe2−3N and γ′-Fe4N phases which constituted the compound layer were affected by the gas composition in the N2-H2 gas mixture atmosphere and also by the carbon content of specimens. In the specimens of higher carbon contents, γ′-Fe4N monophase was formed in the lower N2 gas atmosphere.
(2) In the 20% N2 gas atmosphere, the thickness of the compound layer was hardly influenced by the carbon content, but, in the 80% N2 gas atmosphere, the thickness increased with an increase in carbon content.
(3) The depth of the diffusion layer decreased with an increase in carbon content.
(4) The wear characteristic of the ion-nitrided carbon steels little depended on the phase of the compound layer, the thickness of the compound layer (about 7∼16 μm) and the carbon content, and the ion-nitrided carbon steels showed far better wear resistance than the normalized carbon steels.
(5) In the carbon steels, the compound layer contributed greatly for wear resistance.View full abstractDownload PDF (672K) -
Shojiro Ochiai, Makoto Mizuhara, Yotaro Murakami1977 Volume 41 Issue 6 Pages 625-631
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDeformation and fracture behaviour of carbon fibre-reinforced copper matrix composites with very weak interfacial bond, which were prepared by the plating and vacuum hot-pressing technique, were investigated. In spite of the weak interfacial bond, the externally applied load was transferred to the fibres owing to both mechanical interaction between the fibres and the matrix and compression on the specimen in the chucks. The mechanical interaction between the fibres and the matrix in ths case of weak or debonded interface was examined by the multiple-fracture test of single fibre-composites. Most composites with a higher fibre volume fraction exhibited splitting due to their weak transverse strength. As the transverse strength increased with increasing strength of interfacial bond and decreasing fibre volume fraction, splitting occurred for the higher fibre volume fraction at a given (weak) strength of the bond. Effects of the interfacial bond on fracture behaviour, especially on splitting and crack propagation, were discussed. Most of the measured values of ultimate tensile strength of the composites were lower than those calculated by the rule of mixtures.View full abstractDownload PDF (907K) -
Shuntaro Terauchi, Hiroshi Matsumoto, Takashi Sugimoto, Kiyoshi Kamei1977 Volume 41 Issue 6 Pages 632-637
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe Ti-Mo phase diagram was investigated by optical microscopic observation, electrical resistance measurement, X-ray diffraction and transmission electron micrographic observation.
The results obtained are summarized as follows:
(1) The miscibility gap exists in the region above 675°C where no gap has been reported previously. The maximum temperature of this miscibility gap is 795°C for Ti-32.5 wt%Mo alloy.
(2) The β1\ ightleftarrows(α+β2) monotectoid reaction is found at 675°C and the monotectoid point lies at the composition range from Ti-20 to 22.5 wt%Mo.View full abstractDownload PDF (841K)
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