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Volume 42, Issue 6
Displaying 1-17 of 17 articles from this issue
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Yoshisada Ueda, Mitsuo Niinomi1978 Volume 42 Issue 6 Pages 543-549
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCommercial pure Fe, Fe-Si, Fe-Cr, Fe-Ni, Fe-Cu, Fe-Mn and Fe-C alloys were dipped into molten aluminium (99.8%Al) at 700, 750 and 800°C for various times. The alloy layers formed were examined by X-ray and EPMA analysis, and the hardness and thickness of the alloy layers were also measured. The alloy layer formed on each ferrous alloy is mainly composed of FeAl3 and Fe2Al5, and much FeAl3 is near the adhered aluminium and no FeAl3 near the base metal. Fe2Al5 occupies the major portion of the alloy layer. For commercial pure Fe, Fe-Si, Fe-Cr, Fe-Ni and Fe-Mn alloys, the Fe-Al solid solution exists inside the Fe2Al5 layer. The alloying elements in the base metal reduce the thickness of the alloy layers, especially Si, Ni and Cu. The alloy layers formed on commercial pure Fe, Fe-Si, Fe-Cr, Fe-Ni, Fe-Mn and Fe-Cu alloys are tongue-like and that formed on Fe-C alloy is band-like. In the latter case, however, a slightly tongue-like shape appeares at lower temperatures. The hardness of each alloy layer near the base metal is higher than that near the adhered aluminium. The alloy layer formed on the Fe-C alloy is a little harder than that on the other alloys.View full abstractDownload PDF (732K) -
Yoshisada Ueda, Mitsuo Niinomi, Masamichi Sano1978 Volume 42 Issue 6 Pages 549-555
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe controlling step of dissolution of ferrous alloys into molten aluminium was studied. Commercial pure iron, Fe-Si, Fe-Ni, Fe-Cu, Fe-Mn and Fe-C alloys were dipped into molten aluminium (99.8%) at 700, 750 and 800°C for various times. The rate of dissolution of each alloy into molten aluminium was examined theoretically from the viewpoint of natural convection mass transfer. For the dissolution of Fe-Cr, Fe-Cu and Fe-Ni alloys at 700°C, the experimental value of mass transfer coefficient kob is nearly equal to the theoretical value kc. Therefore, the dissolution of these alloys is controlled by the diffusion of Fe in molten aluminium. At 750 and 800°C, kob decreases with dipping time. This is due to the increase of the resistance of the chemical reaction or mass transfer in the compound layer. For Fe-Si alloy, kob is a little larger than kc. The resistance of chemical reaction or mass transfer in the compound layer is negligible. For commercral pure iron, kob is smaller than kc by about 30∼50%. The resistance of the chemical reaction or mass transfer in the compound layer is not negligible. For Fe-Mn alloys, kob is smaller than kc by about 40∼70%. In addition to the mass transfer in aluminium, the chemical reaction or mass transfer in the compound layer controls the dissolution of the alloy. For Fe-C alloys, kob is much smaller than kc. The dissolution of these alloys is controlled by the chemical reaction or mass transfer in the compound layer.View full abstractDownload PDF (673K) -
Naotsugu Inakazu, Hisashi Yamamoto, Ichizo Tsukuda1978 Volume 42 Issue 6 Pages 555-562
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to study the influence of the mean tensile strength and deformation bands on the lattice rotation in copper single crystals during drawing, force measurements were carried out on the wires given various reductions, and the orientational changes with the development of deformation bands were investigated by means of X-ray pole figure determination.
The results obtained are as follows:
(1) The forming process of deformation bands in copper single crystals during drawing depends on the initial orientation along the wire axis and the rotation of the wire axis is explained by considering the active slip systems in the relative resolved shear stress curves. The rotations of the wire axis toward the [100] and [111] directions develop two kinds of deformation band which intersect at right angles, while the rotation of the wire axis toward the [111] direction developes one kind of deformation band.
(2) When the new deformation bands are developed in the matrix and the wire axes are reached the line [100]-[111], the mean tensile strength during drawing markedly decreases. Also, it has been observed that the wire rod, having ⟨111⟩ parallel to the drawing direction, showed the highest value of the mean tensile strength.View full abstractDownload PDF (820K) -
Tohru Watanabe, Yoshimi Tanabe, Nobutake Imamura1978 Volume 42 Issue 6 Pages 562-566
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIncreasing the reducing agent (NaBH4) added into a plating bath results in an increase of boron contained with the electroless plating N-B alloy film. The structure of the obtained plating film continuously changes from crystalline to amorphous with increasing boron content.
In this paper, the magnetization-temperature characteristics of these various films were studied. The result showed that the saturation magnetization-temperature curve in Ni-B amorphous alloy films cannot be fitted to a Brillouin functional curve which is usually possible in general nickel alloys, but described as a smooth curve which is concave upwards. When the structure of plating films change from amorphousness to a structure of aggregation of very fine crystals, the curve becomes a synthesic one of the concave upwards curve described above and a Brillouin functional curve obtained in general ferro-magnetic substances and finally a complete Brillouin functional curve. Such a unique phenomenon has not yet been reported in the investigations of amorphous alloys prepared by rapid quenching, sputtering or any other methods. It is considered that this phenomenon is a unique behaviour observed in only the Ni-B amorphous alloy film prepared by electroless plating.View full abstractDownload PDF (459K) -
Kazutoshi Shimogori, Hiroshi Sato, Haruo Tomari1978 Volume 42 Issue 6 Pages 567-572
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn investigation was carried out on the crevice corrosion of titanium and titanium-palladium alloy in NaCl solutions at 100∼250°C by means of immersion tests and electrochemical measurements, in order to study the effect of dissolved oxygen concentration, pH, chloride ion concentration and temperature of the solutions.
The results obtained are summarized as follows.
(1) The susceptibility to the crevice corrosion of titanium increased at the higher temperature and chloride ion and dissolved oxygen concentrations and at the lower pH of the solutions. In paticular, crevice corrosion was observed even at a low chloride ion concentration of less than 1% where in titanium has been hitherto considered to be passive.
(2) The passive current density of titanium increased with increase in temperature and decrease in pH of the solution. The effect of the temperature was remarkable, whereas that of the chloride ion concentration was very small.
(3) From the measurements of the TiO2 film thickness formed on titanium in the crevice, it was predicted that both the dissolved oxygen concentration and pH in the solution wtihin the crevice decreased very rapidly. These results indicate that crevice corrosion could occur in the early stage.
(4) In titanium-palladium alloy, on the other hand, no crevice corrosion was observed even in the most severe condition used in the present work.View full abstractDownload PDF (519K) -
Atsushi Oguchi, Minoru Nobuki, Minoru Otaguchi, Yoshinari Kaieda1978 Volume 42 Issue 6 Pages 573-576
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn apparatus for bending tests under high pressures and high temperatures up to 1000 MPa and 1000°C has been designed and constructed. Argon gas is used as pressure transmitting medium. A high pressure vessel of the three-layer vertical cylinder type is equipped with an electric furnace in which a bending equipment is provided. Standard dimensions of rectangular specimens are 3 mm×3 mm in cross-section and 20 mm in length. The maximum measurable deflection is 5 mm and the bending speed can be varied from 0.2 to 4 mm/min. The test can be carried out successively using the apparatus in which 50 specimens at maximum are set beforehand.View full abstractDownload PDF (304K) -
Atsushi Oguchi, Yoshinari Kaieda, Minoru Nobuki, Minoru Otaguchi1978 Volume 42 Issue 6 Pages 577-582
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to study the mechanical properties of brittle materials, bending tests have been carried out for a polycrystalline Fe-Al-Si alloy containing 6.22%Al and 9.63%Si (Sendust) under high pressure and high temperature up to 800 MPa and 900°C. The transition temperature from brittle to ductile decreased from 770 to 650°C by application of a pressure of 800 MPa. At lower temperatures, no distinct change in fracture stress due to testing temperature was seen at atmospheric pressure. However, under 800 MPa, it increased with increasing temperature and the difference was almost the same order of magnitude as the applied pressure. At temperatures higher than about 860°C at atmospheric pressure and about 720°C under 800 MPa, the material could be deformed largely. But, many grain boundary cracks were induced on the specimen deformed at atmospheric pressure, while the formation of cracks was suppressed under high pressure. The pressure required for a rapid increase in ductility without cracks at a given temperature was almost the same order as the yield stress at that temperature.View full abstractDownload PDF (803K) -
Hiroyasu Mitani, Hiroshi Nagai, Mikio Fukuhara1978 Volume 42 Issue 6 Pages 582-588
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSintering characteristics of TiN-Ni mixed powder compacts were studied by heating them in a gas atmosphere of nitrogen, hydrogen or argon, or in a vacuum.
Shrinkage during sintering was disturbed in all of the gas atmospheres, whereas in a vacuum it was promoted remarkably accompanying the occurrence of the liquid phase and denitridation. The solubility of nitrogen in the nickel phase was very small and the composition of the titanium nitride phase equilibrated with the nickel phase was slightly lower than stoichiometric, ie., TiN0.99.
The solid solubilities of TiN1−x in the nickel phase at various temperatures were determined by X-ray diffraction, and the maximum solubility of 5.2 wt% was found at 1350°C.View full abstractDownload PDF (740K) -
Mikio Fukuhara, Hiroshi Nagai, Hiroyasu Mitani1978 Volume 42 Issue 6 Pages 588-592
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUltra-fine powder of TiN was prepared by the vapor phase reaction of TiCl4 with H2 and NH3 in a nitrogen plasma jet. The particles of the obtained TiN powder were single crystals having a constant lattice parameter of 4.2418×10−10 m, which was not affected by the flow rate of ammonia gas. The particle sizes were in the range of 5×10−9∼5×10−8 m, which can be controlled by changing the electric power of the plasma jet and the flow rate of ammonia gas. The optimum condition for the powder preparation was 6 kW in the electric power and 3.3×10−3 dm3/s in the flow rate of ammonia gas. When NH4Cl was removed from the powder produced in this condition by heating at 210°C for 7.2×102 s in a hydrogen atmosphere, the combined nitrogen increased to 22.42 wt% and the oxygen content decreased to 3.75 wt%.View full abstractDownload PDF (462K) -
Tokuhiko Nishida, Tsuyoshi Kikuchi, Takashi Sato, Tadashi Ichiyama1978 Volume 42 Issue 6 Pages 593-599
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStudies on the atomized iron powder compacts were carried out in order to prepare magnetic cores of electric motors by powder metallurgical processing. Iron powders and powdered resin were mixed and compacted into toroidal cores by cold pressing. These compacts were cured to polymerized resin at 150°C.
Dependences of green densities of the compacts and magnetic properties on particle size, size distribution, shape and purity of the atomized iron powders were investigated. It was shown that the compacts made from coarse, irregular-shaped atomized powders are suitable for the magnetic cores. As to the influence of impurities, small amounts of C, N and P markedly deteriorated the magnetic properties of the compacts and the compressibility of the powders. Annealing treatments were effective in reducing the core loss of the compacts.View full abstractDownload PDF (697K) -
Tokuhiko Nishida, Shozo Mizoguchi, Masao Yamamiya, Toshio Hashizume, Y ...1978 Volume 42 Issue 6 Pages 600-605
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to produce iron powders suitable for magnetic cores, oxidation, compressibility and heat treatment of atomized iron powders were studied.
The results were summarized as follows:
(1) It was shown that 80% of the total oxygen content of powders as atomized contributed to the surface layer as oxide and the remainder to oxide inclusions.
(2) Oxide inclusions were distributed in network form. The powders containing P above 0.01% showed the enrichment of phosphorus along the network of oxide inclusions.
(3) As to the effect of impurities on the compressibility of iron powders, the green density of compacts was decreased by C, N, P, Si, Mn and O in decreasing order of effectiveness. With regard to the grain size, the green density increased with coarsening ferrite grain.
(4) Deoxidization of the molten iron by carbon before atomizing was effective in decreasing the oxide inclusions of the powders. Decarburization was easily done by wet hydrogen treatment.
Based on these results, we proposed an appropriate heat treatment, “two-step treatment”, to produce atomized iron powders with high compressibility and magnetic properties.View full abstractDownload PDF (1025K) -
Shigeo Matsushima1978 Volume 42 Issue 6 Pages 606-611
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTension and tensile fatigue tests of water-quenched Cu-Al alloy (β2 phase) with 10 wt%Al have been performed at high temperature in vacuum. The relations among tensile strength σB (strain rate 0.003 s−1), temperature T, cyclic tensile stress (of maximum value σ0) and fatigue life N (number of stress cycles to fracture) are approximately given by
(This article is not displayable. Please see full text pdf.)
\ oindentwhere N0=103, B=10, σB*=8.24×108 Pa, B*=−6.5×10−6 K−2, and T0=270 K.
The expression of the tensile fatigue strength derived from known condition of fatigue failure and deformation is found to agree with the above experimental relation.View full abstractDownload PDF (368K) -
Osamu Haida, Toshihiko Emi1978 Volume 42 Issue 6 Pages 612-617
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCoarsening of globulite- and/or dendrite arm-spacing in the mushy zone of Fe-30 wt%Cu alloy during isothermal holding has been investigated by in situ observation with a modified high-temperature microscope. It is for the first time that in metal, remelting of thin or thin portion of secondary arms is observed to occur during the holding. The average dendrite element spacing, dp, is found to increase exponentially with isothermal holding time, θ, to give dp=const·θα with α ranging from 0.10 to 0.14.
The observed mode of remelting is consistent with the model proposed by Kattamis-Coughlin-Flemings (KCF), but the above value of α is much smaller, about 1/3, than that derived from the KCF model. A possible source of the inadequacy of the KCF model is further discussed in terms of the initial distribution of secondary arm spacings to partly resolve the discrepancy.View full abstractDownload PDF (917K) -
Masayasu Kawahara, Yasuo Ozima, Kenji Morinaga, Tsutomu Yanagase1978 Volume 42 Issue 6 Pages 618-623
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe measurements on the electrical conductivity of Na2O-SiO2-MgO and CaO-SiO2-MgO melts have been conducted to find out the behavior of MgO in these systems.
The electrical conductivity decreased with increasing MgO content in the Na2O-SiO2 system, but it slightly increased in the CaO-SiO2 system. The electrical conductivity gave a good linear relationship with Na atomic % in the Na2O-SiO2-MgO system and Ca+Mg atomic % in the CaO-SiO2-MgO system. Mg2+ ions contributed to the electrical conductivity in the CaO-SiO2 system to such a degree as shown by Ca2+ ions, whereas it will give no contribution in the Na2O-SiO2 system, probably due to the formation of complex anions. Compared with the viscosity data in the previous paper, the SiO2 equivalent to MgO was calculated, and the structural aspects of Mg2+ in the melt were estimated.View full abstractDownload PDF (479K) -
Yutaka Shinata, Matsunobu Uramoto, Yasutoshi Saito1978 Volume 42 Issue 6 Pages 623-629
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA new type of exoelectron microscope was constructed for the examination of mechanically worked metal surfaces by means of the accompanying exoelectron emission under ultraviolet radiation stimulation. The metal surface to be examined was placed in a gas-tight chamber and scanned line by line. The microscope installed the scanning mechanism in which the specimen surface was moved along the X- and Y-directions with a spot of ultraviolet light fixed. A picoammeter or a gas-flow type G-M counter was used to detect the exoelectron emission. The emitted electrons made a magnified image of the specimen surface on the fluorescent screen of an oscilloscope. Scratched, tensile- and fatigue-deformed surfaces of polycrystalline aluminum were examined in air or counting gas with the exoelectron microscope. The brightness modulation image qualitatively revealed the exoelectron emission activity on the specimen surface. Quantitative information on the exoelectron emission was obtained by the three-dimensional effect from the Y-axis modulation image wherein the signals of the exoelectron emission were connected to the Y-input of the oscilloscope. The line profile measurements also gave the quantitative intensity of the exoelectron emission along a single scan path of X-axis indicated. The microscope made it possible to recognize sensitively the lapse of time after abrasion, the extent and area of damage during the tensile deformation, and exoelectron-snsitive regions at a given stage during the fatigue process, which were undistinguishable by optical microscopy. The exoelectron microscope proved to be a tool useful for the study of metal surfaces associated with the generation and extinction of a freshly formed surface.View full abstractDownload PDF (1080K) -
Takuzo Sogabe, Shigeoki Saji, Shigenori Hori1978 Volume 42 Issue 6 Pages 629-635
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe formation of microduplex structure in a Cu-Ni-Fe alloy has been studied by hardness measurement and optical and electron microscopy observation. The results are summarized as follows:
(1) The anneal-softning of the cold rolled specimens is very slow, due to the fact that during the earlier annealing stages, modulated structure is formed prior to recrystallization of supersatulated solid solution and dislocations or cell walls are pinned by finely precipitated NiFe-rich phases.
(2) The grain boundary coarsening reaction is accelerated by cold rolling. When the cold reduction rate is more than about 50%, recrystallized Cu-rich grains accompanied by coarsening of NiFe-rich phases preferentially nucleate in the vicinity of the deformation bands and grow as in the case of the grain boundary coarsening reaction. Then, the grain boundary coarsening reaction is suppressed with increasing recrystallized grains.
(3) In the heavily deformed specimen, NiFe-rich phases coarsen anywhere including grain boundaries or deformation bands, and recrystallization can start in the area free of the modulation structure around the coarsening NiFe-rich phase. Therefore, the recrystallized structure consists of fine, equiaxed Cu-rich and NiFe-rich grains (microduplex structure).View full abstractDownload PDF (963K) -
Hiroaki Nakamura, K\={o}ki Gunji1978 Volume 42 Issue 6 Pages 635-641
Published: 1978
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCalcium sulfide disks have been carefully prepared to avoid any contamination by means of a newly-developed sintering method. The electrical conductivity has been measured at temperatures from 650 to 900°C and in the PH2S⁄PH2 range from 0 to 102 with the aid of an alternating current bridge. Because the conductivity was independent of sulfur partial pressure, it was concluded that pure calcium sulfide is a perfect ionic conductor. The specific conductivity can be expressed as follows:
(This article is not displayable. Please see full text pdf.)
\ oindentand the apparent activation energy for the conduction is 165.3 kJ/mol.
The tracer diffusivity of Ca2+ was estimated from electrical conductivity measurements by using the Nernst-Einstein relation. Comparing with the activaion energies of anions in similar crystals, it seems that the divalent calcium cation is the main charge carrier of the electrical conduction.View full abstractDownload PDF (503K)
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