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Volume 23, Issue 6
Displaying 1-13 of 13 articles from this issue
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Kunio Shida1959 Volume 23 Issue 6 Pages 315-318
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the former report, a sintering process and successful results of the experiments to produce sintered Fe-Al-Ni magnet of superior magnetic properties have been reported. The sintering of 12.5%Co, 18%Ni, 11%Al, 6%Cu, bal. Fe system magnet is discussed in this paper from the experimental stand-points, i.e., the dependence of various properties (density, densification parameter, saturate induction, the product, residual induction times coercieve force, rupture strength and pore size distribution) upon the sintering conditions has been investigated. The experimental results obtained are summarized as follows: (1) The process of sintering of Fe-Al-Ni-Co-Cu system was essentially the same as the process of sintering of Fe-Al-Ni system, but the densification rate of specimens has been accelerated by addition of Co and Cu powders. (2) At the sintering temperature of 1100°, a slight pore shrinkage and densification has been found whereas adhesion of powder particles have been promoted very gradually with the time of sintering. (3) When the sintering temperature reached to 1200° a rapid shrinkage of pores has been observed during the earlier stage of sintering, up to 90 minutes. (4) At the higher sintering temperature of 1300° or 1350° the densification and shrinkage of pores were nearly completed in 30 min and was followed by alloying of components which proceeded very rapidly. (5) The effect of sintering temperature upon the various properties (i.e., density, densification parameter, magnetic property) of the magnet was larger than that of sintering time.View full abstractDownload PDF (628K) -
Kunio Shida1959 Volume 23 Issue 6 Pages 318-321
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe relatinoship between the cooling procedure after sintering and the magnetic properties, the hardness, the microstructure of Fe-Al-Ni-Co-Cu sintered magnets was studied. The specimens at their sintering temperature (1350°) were put into a cooling box kept at various temperatures. The experimental results obtained are summarized as follows: (1) A remarkable effect of cooling rate after sintering upon the magnetic properties of the specimens has been found. Excellent magnetic properties could be obtained under the average cooling rate of 1.5∼2.0°C/sec between 900° and 500°, but inferior magnetic properties were obtained under either faster or slower cooling rate. (2) No change of microstructure of the specimens under the various cooling rates has been observed. (3) Excellent magnetic properties could be obtained under the following optimum conditions: i.e.sintering at 1350° for 3∼6 hours in extra-pure hydrogen, and quenching cooling box retained at 700°.View full abstractDownload PDF (661K) -
Hiroshi Asada, Kichizo Koike1959 Volume 23 Issue 6 Pages 321-325
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of quenching in a die and preheating prior to a solution treatment on the structures and the tensile strength of extruded aluminium products have been studied. From the results obtained, it has been concluded that prior heating at a suitable temperature is effective for improving the structural inhomogeneity and the tensil strength of extruded 17S aluminium product.View full abstractDownload PDF (958K) -
Akira Takaoki1959 Volume 23 Issue 6 Pages 325-329
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSChange of ultrasonic attenuation by magnetization in plastic deformed steel was measured at the frequency of 5 Mc/sec. The clear difference of attenuation was observed between the steel specimens deformed plastically and elastically near the yield point. By this experiment it was made clear that the method could be applied for a nondestructive inspection of yielding of steel. Plastic deformation caused by thermal strain was confirmed by this method at the centre of 70φ×280 mm specimen quenched in water at just below Ac1 transformation temperature. Also, six kinds of structural steels were examined by this method and it was shown that this method could be applied to steel which showed no clear yield point. From the measurement of the change of magnetostriction with magnetization, it was also recognized in plastic-deformed specimens that the change of attenuation with magnetization was similar to that of magnetostriction.View full abstractDownload PDF (757K) -
Eihachiro Tanaka, Fumio Hataya1959 Volume 23 Issue 6 Pages 330-332
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe elastic anisotropy of Cu-Be alloy (Be 2.23%, Ni 0.25%) foil has been examined. The results were as follows: (1) The elastic modulus of cold rolled foils (0.072∼0.021 mm thickness) reached the maximum at 15° and 75° from the rolling direction and the minimum at 0°, 45° and 90° from the rolling direction. (2) The minimum elastic anisotropy of cold rolled foils was observed at the cold rolling degree of 15 to 47%. (3) The directions of maximum and minimum elastic moduli of cold rolled foils are not changed by aging.View full abstractDownload PDF (441K) -
S. Takeuchi, S. Kachi, T. Satow1959 Volume 23 Issue 6 Pages 333-336
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPure thorium metal powder was prepared in inert atmosphere by electrolysis of potassium thorium fluoride dissolved in molten potassium-sodium chlorides eutectic bath using a graphite crucible as the anode and a molybdenum rod as the cathode. The relations between anode current density and current efficiency, thorium salt concentration and current efficiency, and cathode current density and crystal size distribution of thorium powder were studied. The results of spectrographic analysis of impurities are given. The powder was fused to a coherent mass in inert gas atmosphere with a non-consumable electrode arc furnace. The hardness and the microstructure of the arc melted thorium button are shown. Experiences on health monitoring in the laboratory of thorium metallurgy are also described.View full abstractDownload PDF (676K) -
S. Takeuchi, S. Kachi, T. Satow1959 Volume 23 Issue 6 Pages 336-340
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHigh purity thorium metal was prepared by electrorefining crude metal in molten potassium thorium fluoride dissolved in NaCl-KCl bath. In this process, noble or base metallic impurities such as Fe, Co and rare earths were thoroughly eliminated, and high purity thorium crystals were obtained as cathode deposit. The purity and the crystal size of the refined metal was improved by lowering the applied voltage to about 0.4 V. The hardness of the crystal was about 33∼42 in V.H.N., and comparable to that of standard iodide thorium. The button ingot was arc-melted and was cold-rolled to a thin foil of 0.05 mm thick. The microstructure and the other metallurgical properties are also described.View full abstractDownload PDF (702K) -
Ryuzo Ueda1959 Volume 23 Issue 6 Pages 340-343
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSWO3 single crystals were mounted on the sharply pointed end of a platinum wire and exposed to heated hydrogen gas at one atmospheric pressure in the specimen-treating adaptor for the electronmicroscope, previously devised by the author and others, and the morphological and chemical changes at a certain chosen region of the specimen were followed by taking micrographs and selected-area-diffraction patterns. In the earier stages of reduction, WO2 particles and β-W particles were formed in the oxide crystal, the latter being completely transformed into α-W particles when heated above 700°. The pattern of a arangement of these tungsten particles can differ markedly as one passes from one oxide crystal to another. α-W particles sufficiently grown always gave rise to elongation of diffraction spots, and also often to extinction contours, though diffuse, in the micrograph. Based on these observations, an attempt was made to picture the way of formation and growth of W-particles.View full abstractDownload PDF (603K) -
Hideo Abe, Fumio Seki1959 Volume 23 Issue 6 Pages 343-347
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSVariations in the integrated intensities of (111), (200), (220) and (113) diffraction lines and in the intensities of the various areas of the (200) pole figure on annealing cold-rolled 50-Fe 50-Ni alloy were observed by an X-ray diffractometer. Prior to the primary recrystallization, sharpening of the cold-rolling texture is observed, probably caused by the polygonization. Initial growth of the cube-oriented recrystallized grains occurs without any appreciable decrease in the intensities of the areas near the poles of (110)[\bar112], (112)[11\bar1] and near-(123)[1\bar21] orientations in the (200) pole figure, during which the back-ground intensities around the poles of (100)[001] orientation are conspicuously lowered. The results show that the nuclei of the cube-oriented recrystallized grains are formed by the Burgers-Cahn mechanism in the local curvature of the cube-oriented deformed matrix.View full abstractDownload PDF (738K) -
Toshio Doi1959 Volume 23 Issue 6 Pages 347-351
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe structure changes were studied microscopically Cu-3%Ti alloys, which were solution-treated and aged at temperatures from 550° to 700°. The results obtained were as follows: (1) The grain boundary reaction were observed on the specimens aged at the temperature between 550° and 600°. The precipitates started to grow at grain boundaries, and spread gradually into the matrix. These regions with precipitates have the lamellar pearlite type structure, and the distance between the layers was about 2 microns or more. (2) The rate of growth of the pearlitic regions increases with higher aging temperature, as shown in the isothermal transformation curves. (3) Together with the pearlite type structure, Widmanstätten type structure was observed for the specimens which were aged at the temperature between 620° and 680°. (4) When aged at 700°, only Widmanstätted type structure could be found without any traces of pearlitic region. The size of the individual precipitates which can be found within the Widmanstätten structure increases with longer aging time.The shape of these precipitates was of a striped plate, and the distance between them is about 3 micronns. (5) The activation energy of the grain boundary reaction calculated from the data is about 45,000 cal/mol.View full abstractDownload PDF (1303K) -
Toshio Doi1959 Volume 23 Issue 6 Pages 351-355
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPrecipitates of Cu-3%Ti alloys were extracted with by 50% nitric acid from the specimens aged for 1 hour at 600° and 700°C respectively, and their crystal structure was studied by means of X-ray as well as electron diffraction. It was shown, in both cases, that the precipitates were β′-Cu3Ti with a sightly deformed close-packed hexagonal lattice. The direction of the trace of the precipitates in the pearlitic region which appeared at grain boundaries—discontinuous precipitation—was the same as that of one of the traces of precipitates in the adjacent grain. Therefore, the crystal orientation of the pearlitic region was the same as in the adjacent grain. The plane of the matrix on which the precipitation of Widmanstätten type takes place was determined by three methods, and the results obtained by use of these methods were in good agreement. that is, β′-Cu3Ti precipitates were formed on the (111) planes of the matrix. The following explanation was suggested by the author: The growth of precipitates in the pearlitic regions—discontinous precipitation—may proceed by means of diffusion of the solute atoms along the boundary surface between the pearlitic regionand the bonded supersaturated solution. On the other hand, the growth of the Widmanstätten type precipitates-continuous precipitation—may be controlled by means of bulk diffusion of the solute. As the grain boundary diffusion occurs at relatively lower temperatures than the bulk diffusion, it is reasonable that discontinuous precipitation occurs at relatively lower temperatures, but continuous precipitation occurs at relatively higher temperatures.View full abstractDownload PDF (739K) -
Yoshio Kubota1959 Volume 23 Issue 6 Pages 355-359
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSZn powder is usually produced by the distillation method, but sometimes also by electrolysing a zincate solution. A systematic and comparative study of E-Zn and the distilled Zn powder (D-Zn) from the physical and chemical standpoints has been undertaken. The general conclusion is that the high reactivity of E-Zn powder does not depend upon the impurities as is usually believed, but essentially upon some physical properties, such as the specific surface area, the layer growth in dendrites and the crystal imperfection. This 1st report concerns with the comparative study in reactivity of E-Zn and D-Zn, which are almost identical in the kinds and the amounts of chemical impurities. The rate of dissolution in acids and in NaOH aq, the rate of reduction by NaHSO3 and chrysoidin in solution were measured. In all these reactions, E-Zn was found much more reactive than D-Zn, especially in those accompanied by H2 evolution. In the following studies, therefore, we will take, as the measure of reactivity of Zn powder, the rate of H2 evolution in HCl, which is convenient to determin.View full abstractDownload PDF (701K) -
Yoshio Kubota1959 Volume 23 Issue 6 Pages 359-362
Published: 1959
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe chemical reactivity of Zn is usually attributed to the presence of impurity elements. The present paper however shows that the “Localization Theory” does not hold in our case. The chemical reactivity as determined by measuring the rate of H2 evolution in HCl is more than ten times as high in E-Zn as that in commercial products of “high grades” which are indeed much less pure. In the laboratory products whose trace impurities are almost the same in quality and quantity, the reactivity of E-Zn varies with electrolysing conditions, but always exceeds that of D-Zn by the factor of about ten.View full abstractDownload PDF (714K)
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