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Volume 47, Issue 3
Displaying 1-16 of 16 articles from this issue
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Yoshiaki Ikeda, Tohru Watanabe, Yoshimi Tanabe, Jun Hosoi1983 Volume 47 Issue 3 Pages 175-179
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe influence of boron concentration on the structure of electroless deposited Ni-B films has been investigated by high resolution electron microscopy.
The lattice images indicated that the film structure changed continuously from a crystalline to an “amorphous-like” state with increasing boron content. The 5.5 at%B film consisted of fine crystals with the grain diameter of about 10 nm. The 7.9 at%B film was microcrystalline with many structural defects, while the 17.1 at%B film contained microcrystals of about 1 nm in the amorphous matrix. Upon heat-treatment of the 17.1 at%B film at below the crystallization temperature, neighbouring or overlapping fringe patterns appeared. These results strongly support the presence of an amorphous-like structure in the as-deposited 17.1 at%B films.View full abstractDownload PDF (1713K) -
Akira Tahara, Yasunori Hayashi1983 Volume 47 Issue 3 Pages 180-184
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPermeation process of hydrogen through nickel is examined under oscillating pressure conditions at temperatures between 650 and 1000 K with specimens of varing thicknesses. The frequency dependence of the phase difference in the oscillating permeation response is analyzed taking the diffusion and dissolution processes into account. In a thick specimen, the response of the surface process for dissolution of hydrogen into metal can be neglected and the permeation response is explained by diffusion process alone. In a thin specimen, however, the permeation response deviates from that of the diffusion control, and the surface process is not negligible.
The surface response is discussed with respect to the kinetic equations of adsorption, desorption and absorption processes. In nickel, the adsorption process is proved to play a more important role in the surface reactions compared with the absorption process.View full abstractDownload PDF (658K) -
Yuji Imashimizu, Jirô Watanabé1983 Volume 47 Issue 3 Pages 185-190
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe (111) surface of copper crystal was etched anodically at constant potentials, 0, 20 and 40 mV vs SHE, in the solution containing 5 kmol·m−3 NaCl, 0.25 kmol·m−3 NaBr and 10−4 kmol·m−3 CuCl, and the dissolution rate at dislocation sites was determined through a measurement of three-dimensional size of the corresponding etch pits from optical and interference microphotographs taken at sucessive times. The width h and the depth d of the etch pits increased rapidly at an early stage of etching and then increased linearly with an increase of etching time t. It was to be added also that the etch pits grew larger when the applied potential was higher. However the side slope d/h of the etch pits decreased with an increase of t and tended to approach asymptotically a constant value. For a given potential, the anodic current density i increased slowly during the stage where the etch pit size, h and d, increased at a constant rate, and finally reached to a constant value. It was shown from the analysis of the above measurements that the i-t relation could be explained on the basis of dissolution processes during dislocation etch pitting.View full abstractDownload PDF (906K) -
Yuji Ikeda, Kazuyoshi Nii1983 Volume 47 Issue 3 Pages 191-197
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to examine the influence of tensile stress on the high temperature oxidation, wire specimens of heat resistant Fe base alloys were oxidized under a constant load in O2 or in air at 1173 K. It was anticipated that the oxidation of loaded specimen is accelerated because of the breakdown of protective scale due to elongation of the alloy substrate. In the case of ferritic alloys (Fe-20Cr and Fe-18Cr), however, no accelerated oxidation was observed in comparison with the oxidation without load. The absence of acceleration is attributed to rapid healing of scale on the ferritic alloys by virtue of a large diffusion rate of Cr in the alloys. On the other hand, the oxidation of an austenitic alloy Fe-20Cr-12Ni was somewhat accelerated under an average strain rate of 2.8×10−6 s−1 and the oxidation of an Fe-17Cr-6Ni alloy was very severely accelerated under the same strain rate. This acceleration is attributed to smaller diffusion rates of Cr in the austenitic alloys. A threshold of average strain rate to acceleration was observed to be of the order of 2×10−6 s−1.View full abstractDownload PDF (3313K) -
Atsushi Nishikata, Shiro Haruyama1983 Volume 47 Issue 3 Pages 198-204
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe kinetics of Pt/Pt(II), Ni/Ni(II) and Ag/Ag(I) electrodes has been studied in LiCl-KCl eutectic melt at 773 K by linear potential sweep and galvanostatic double pulse methods. All the electrodes exhibited their reversible potentials in the melts containing respective metallic ions (2×10−2∼2×10−1 mol%). The cathodic polarization curves obtained by the linear potential sweep method exhibited a limiting current controlled by diffusion of metallic ions, whereas the anodic branch exhibited Tafel lines, the slope of which was (2.3RT/2F) on Pt and (2.3RT/F) on Ag electrode. The exchange current densities for charge transfer obtained by the galvanostatic double pulse method increased with increasing concentration of metallic ions from 1.43 to 12.50×104 A/m2 on Pt/Pt(II), 4.70 to 14.03×104 A/m2 on Ni/Ni(II) and 6.98 to 18.95×104 A/m2 on Ag/Ag(I), respectively. These i0 values were, however, 103 times as large as those obtained by Tafel extrapolation of the polarization curves. The activation energies obtained from the Arrhenius plots of the exchange current densities were 137(Pt), 46(Ni) and 13(Ag) kJ/mol, respectively. The interfacial capacitance increased with increasing concentration of metallic ions from 1 to 10 F/m2.View full abstractDownload PDF (905K) -
Takakazu Suzuki, Kyoji Takahashi1983 Volume 47 Issue 3 Pages 205-210
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is known that zinc is stable in a weak basic atmosphere and becomes more stable in a presence of carbon dioxide.
The corrosion inhibitive effect and its mechanism of volatile Benzylammonium-N-benzylcarbamate (BAC) which satisfied the above-mentioned condition to zinc were investigated by means of immersion test, potentiostatic polarization measurement, multiple reflection infrared spectroscopy and so on. BAC was prepared by passage of dry carbon dioxide through a cooled ether solution containing 5-10% Benzylamine.
Immersion test at 333 K (60°C) for 576 ks (160 h) showed the following results; when BAC was added by 1×102 ppm, 1×103 ppm and 1×104 ppm in an aqueous solution, the corrosion of zinc was inhibited to ca. 89%, 92% and 95%, respectively.
Potentiostatic polarization measurements showed the following results; the anodic polarization behavior of zinc in the deaerated 0.02 kmol/m3 Na2SO4 solution containing BAC showed the inhibitive effect, but the cathodic polarization behavior did not. It means that containing BAC played a role in the inhibition of dissolution of zinc.
The reflection infrared spectra, which have characteristic absorption bands at 1540 cm−1, 1400 cm−1 and 840 cm−1, showed that zinc carbonate (ZnCO3) was formed on the zinc surface after immersion for 46.8 ks (13 h) in the solution containing less than 2.5% BAC.
As to the pH dependence of corrosion inhibitive effect, the BAC solution immersion test showed that the inhibitive effect was clearly decreased with decreasing pH value in the region less than 10. From a polarization measurement, it was presumed that the reason for it was a difficult formation of passivating film in such a region of pH.
In the solution containing of BAC 2.5% or more infrared spectroscopy and chemical analysis clarified that a complex was formed on the zinc surface.View full abstractDownload PDF (802K) -
Shunichi Suzuki, Koichi Sato, Yoshisuke Nakamura, Haruno Okochi1983 Volume 47 Issue 3 Pages 211-216
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe emission spectrochemical analysis of main components (Ni, Cr, Co, Mo and W) in nickel-base superalloys has been developed. The samples were recast with electrolytic iron. By this method it was possible analyse them using low alloy steel standard samples for instrumental analysis. At first the experimental conditions of recasting with electrolytic iron were investigated and determined as follows. Special crucibles (alumina type) were used, samples were put on the bottom of them, and block shapes of electrolytic iron were used for dilution. A permissible amount of matrix elements with exception of iron was examined. For the determination of chromium and cobalt, amounts less than 20% of them were permissible, and for tungsten, those less than 10% up to which the effect was examined did not influence, and those less than 10% of them in the case of nickel and those less than 5% in the case of molybdenum were desirable. Consequently, when recast with electrolytic iron, the amounts of matrix elements with exception of iron were controlled within less than about 7% taking into consideration of experimental errors. For the analysis of these samples, the internal standard method was not adequate, and so the fixed time integration method was used. The relation between analytical sensitivities and coefficients of correction was investigated. The coefficients of correction were constant regardless of sensitivities, when calibration curves passed through near the origin. The fine linear relationship of the gradient −1 was obtained between analytical values and dilution rates on a logarithmic section paper. The reproducibility of the established method was examined using 10 samples of same dilution rate. Various nickel-base superalloys standard samples, cobalt-base superalloys and nickel-base alloys for study were analysed and satisfactory results were obtained.View full abstractDownload PDF (801K) -
Kazumichi Yamamoto, Susumu Hayashi, Yoshiyuki Miwa, Nobuhiro Iguchi1983 Volume 47 Issue 3 Pages 217-224
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn situ microstructual observations at subzero temperature range as to the martensitic transformation under elastic tensile stresses applied have been performed in an Fe-30%Ni alloy. Results obtained are as follows:
(1) The increase of Ms of athermal martensites due to applied stress has been confirmed by the in situ observations.
(2) It was recognized by the continuous observations in isothermal conditions that the nucleation and growth of surface martensites undergoing the schiebung transformation were under the influence of applied stress.
(3) The TTT diagram was indicated, being arranged at each applied stress. By this diagram it was clarified that the incubation period was decreased due to the applied stress.View full abstractDownload PDF (2175K) -
Riyoji Kawachi, Hirokazu Tujii, Makoto Kawamoto, Kunio Okabayashi1983 Volume 47 Issue 3 Pages 225-230
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe impact wear of an annealed 0.16%C steel and a pearlitic cast iron with flaky graphites was examined and compared with their sliding wear. The impact wear machine used was of such a type that a specimen attached to the pendulum was striked against a rotating disc of annealed 0.55%C steel; at the same time as the impact load was brought onto the surface of specimen, the friction force acted, of which the speed was also called the sliding speed with respect to the impact wear in the present work.
Impact wear tests were carried out under dry conditions at the impact energy of 8.7×10−2−5.4 J and the sliding speed of 2.1-15.0 m/s. At the same sliding speeds, dry sliding wear tests were also done under the applied load of 9.8-19.6 N.
Results obtained are summerized as follows:
(1) The marked running-in wear with large wear rate appears to be followed by the equilibrium wear with smaller constant rate in the impact wear of steel, but the impact wear loss of cast iron increases proportinally with the number of impact from early stage.
(2) There is a maximum wear rate in the impact wear rate-sliding speed diagram and similarly in the sliding wear rate-sliding speed one. The sliding speed at which the wear rate reaches a maximum and the maximum rate become higher and larger respectively with increasing impact energy. But the former is considerably higher than that in the sliding wear and besides, contrary to the case of sliding wear, the maximum wear of cast iron appears at lower speed than that of steel.
(3) The hardened layer forms, similarly to the case of sliding wear, on the worn surface striked at higher sliding speeds than the speed at which the wear rate reaches a maximum.
(4) The impact wear resistance of cast iron is extremely inferior to that of steel. The toughness of material is considered to be one of the most important factors controlling the impact wear.View full abstractDownload PDF (1545K) -
Susumu Ikeno, Tetuya Watanabe, Shizuo Tada1983 Volume 47 Issue 3 Pages 231-236
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to investigate the effect of deformation temperatures on serrated yield at relatively high temperature range, tensile tests were performed in Al-0.5, 1, 1.5, 2, 3, 5 and 7%Mg alloys.
Results obtained are as follows:
(1) With rising temperature, strain for onset of serrated yield (εc) became smaller and then larger again till εc reached an almost constant value in Al-7%Mg alloys.
(2) The activation energy for onset of serrated yield was found to be 28.3±5.3 kJ/mol (which was independent of Mg content) in the lower temperature range. The activation energy which was calculated by Charnock’s relation in the relatively high temperature range, increased with higher strain rate and with lower Mg content.
Both the frequency and magnitude of serrated yield in the relatively high temperature range increased with the increase of the amount of strain in Al-7%Mg alloys.View full abstractDownload PDF (900K) -
Masatoshi Fukamachi, Yoshikuni Kawabe, Kozo Nakazawa, Seiichi Muneki1983 Volume 47 Issue 3 Pages 237-242
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTransmission electron microscopy studies were carried out in order to reveal the structural changes in maraging steel as a result of aging. Two kinds of intermetallic compounds of Ni3Mo and Fe2Mo are found to precipitate in the martensite. The precipitation takes place in two stages. Ni3Mo precipitates first and in the latter stage both Ni3Mo and Fe2Mo are found to precipitate in the martensite. The average size of precipitates is about 5 nm in the maximum hardeness state. Relation between the distribution of precipitates and the properties of maraging steel such as strength, temperature dependence of hardening characteristics, and brittleness in early stage of aging is examined. These properties are influenced by the size of precipitates. Specimens containing precipitates smaller than 4 nm have different properties from those with precipitates larger than 4 nm.View full abstractDownload PDF (1624K) -
Tsutomu Ninomiya, Fumiyoshi Miyashita, Giroku Miyatani, Kiyoshi Kamei1983 Volume 47 Issue 3 Pages 243-248
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe anodic polarization curves in the 1 kmol/m3 H2SO4 solution of 50 mass%Ni-(Co+Cr) and 50 mass%Ni-(Co+Ti) alloys containing different quantities of Co, Cr and Ti were measured to investigate the relationship between the electrochemical behaviour and the phase diagram of the alloys. The results are as follows:
(1) It is shown that the transpassivity potential, flade potential, passivation potential and corrosion potential of the 50 mass%Ni-(Co+Cr) alloy in 1 kmol/m3 H2SO4 solution corresponds to the phase change due to different additional elements. In the composition range of α single phase of Ni-35 mass%Co-15 mass%Cr and Ni-25 mass%Co-25 mass%Cr the best corrosion resistance is obtained.
(2) In the case of a 50 mass%Ni-Co-Ti system, the Ti content exerts an effect on the passivity maintaining current density which tends to decreas with increasing Ti content. It appears that the passivation current density is related to the phase diagram.View full abstractDownload PDF (768K) -
Akimitsu \={O}kura, Eiichi Nakata, Shigeo Sakai1983 Volume 47 Issue 3 Pages 249-257
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCarbon fiber reinforced aluminium matrix composites were made by plasma spraying of aluminium powder on carbon fiber and hot pressing in air, whose volume fraction of the fiber was varied from 0.15 to 0.40. Mechanical properties of these specimens were measured at room temperature and at elevated temperature.
The results are as follows:
(1) Carbon fiber is not damaged by plasma spraying of aluminium powder.
(2) Carbon fiber in the pre-form sheet deteriorates under elevated temperature in air, and this deterioration may be caused by inhomogeneous spraying of aluminium powder.
(3) Strength of the fiber reinforced composite materials depends on deterioration of carbon fibers in the composite materials.
(4) Strength of the fiber reinforced composite materials (Vf=0.35) at room temperature is maintained up to 673 K, and it decreases beyond this temperature.View full abstractDownload PDF (2375K) -
Kiyoyuki Ohuchi, Hiroo Takahashi1983 Volume 47 Issue 3 Pages 258-266
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSExtrusion pressure and internal deformation in the hot extrusion of aluminium and copper powder compacts have been studied experimentally and theoretically. At the stage of steady extrusion, the flow pattern of the powder compact is quite similar to that of the fully dense billet. Theoretical analysis is done on the linear flow velocity field with the assumption of the ideally rigid plastic material. The upper bound of the normalized extrusion pressure pm0/Y0 is calculable numerically, where Y0 is the uniaxial yield stress. The extrusion pressure pm for powder compact is determined from pm0/Y0 multiplied by Ye, called the equivalent yield stress. Ye is related to Zener-Hollomon parameter Z in the form of Z=A(sinhβ1Ye)p, proposed firstly by Sellars et al. The coefficients A, β1 and p were determined from some of hot extrusion tests of aluminium and copper powder compacts. Ye−Z relations experimentally determined are used to estimate the extrusion pressures under some other working conditions, and give fairly good results agreeable with experimental ones.View full abstractDownload PDF (1280K) -
Naotsugu Inakazu, Hisashi Yamamoto1983 Volume 47 Issue 3 Pages 266-272
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCopper wires drawn up to 86, 95 and 98% reductions in area were intermediately annealed at 513 K for 1800 s and secondarily drawn. Mechanical testing and determination of {111} pole figure were carried out in order to explain the correlation between the process of fiber texture formation and the mechanical properties in secondary drawn copper wires.
The process of fiber texture formation was well explained by the slip rotation of the systems which should be operative under the triaxial stress system.
The second-drawing texture of the wire which was initially drawn to a reduction less than 95% and intermediately annealed is concentrated around {112}⟨111⟩ and {110}⟨111⟩ orientations, resulting in superior mechanical properties, because these orientations are the stable end ones.
In the case of the wire firstly drawn over 98% reduction, a ⟨111⟩ fiber texture is readily developed by second drawing from the {210}⟨001⟩ component, and thus the workability for drawing is deteriorated, because the slip rotation does not smoothly occur during the excessive drawing after the formation of the ⟨111⟩ fiber texture. Thus, it is necessary to give an intermediate annealing before the first drawing reduction exceeds 95%.View full abstractDownload PDF (940K) -
Akira Okada, Hideyuki Koguchi1983 Volume 47 Issue 3 Pages 272-277
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe graining process and powder metallurgical process were applied to fabricate the CF-Al composite materials. At first, small particles around 0.5 mm in diameter consisting of the carbon fibers and aluminium alloy (CF-Al composite particle), were obtained by stirring a mixture of molten Al alloy and chopped carbon fibers until the alloy solidified to form small particles. Four kinds of metals, i.e. Al, Al-Cu, Al-Ti and Al-Cu-Ti, were tried to mix with carbon fibers. Among them, the Al-Cu-Ti alloy was considered to be most suitable for producing the composite particles, presumably due to the improvement of wattability of Al against carbon fiber by adding a small amount of Ti and the expansion of the width between the liquidus and solidus by alloying Cu. The good wettability and lower melting point may provide the advantage to this “graining process” for the fabrication of the composite particles even by a shorter stirring time at lower temperatures compared with plain Al. Therefore, the damages by the mechanical destruction and chemical reaction between Al and carbon fiber during the stirring process may be decreased. The carbon fibers composing the composite particles were observed to be well covered with thin layers of the alloy.
The pieces of CF-Al composite material were fabricated from these particles mixed with Al powder, compressed into a disk shaped compact and sintered in a vacuum. Their Brinell hardness was 20 to 30% larger than that of sintered Al, however, the bending strength was reduced a little. The mechanical properties may be improved by choosing Al powder as a bonding substance (stamped Al seemed to be better than atomized Al) if suitable size, shape, chemical composition and appropriate sintering conditions are selected.View full abstractDownload PDF (2724K)
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