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Volume 40, Issue 8
Displaying 1-17 of 17 articles from this issue
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Kei Higashi, Hisaaki Fukushima1976 Volume 40 Issue 8 Pages 765-769
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of chloride ions in Watt’s type baths containing various amounts of chloride ions have been investigated by measuring the cathode current efficiency, cathode polarization, rest potential of the electrode, time-dependence of electrical double layer capacity, and stationary electrode polarogram.
The electrodeposition of nickel from higher concentration chloride baths occurs at more noble potentials with corresponding higher current efficiencies than from lower concentration chloride baths and a chloride ion-free bath. Thus, chloride ions in the bath facilitate the electrodeposition of nickel. Double layer capacity data show that specific adsorption of chloride ions occurs at the electrode surface. The pre-wave appeared in the stationary electrode polarogram when chloride ions were added to the chloride ion-free bath. This indicates that adsorbed chloride ions seem to electrocatalyse the nickel deposition by the same effect as that proposed by McCoy et al. in a mercury electrode.View full abstractDownload PDF (410K) -
Kazuyoshi Sekine, Osamu Yoshimura, Takeyasu Inoue1976 Volume 40 Issue 8 Pages 769-774
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSProblem of a unique determination of lattice rotations for crystals undergoing an arbitrarily imposed strain has been considered on the basis of the generalized Taylor type minimum work principle. A mathematical model for slip rotation of grains in a polycrystalline aggregate was formulated by utilizing the concept of the generalized Somigliana dislocation, which was characterized by the variable displacement-discontinuity at a closed surface within the interior of continuum, such as a grain boundary.
From the idea of the force on the generalized Somigliana dislocation, it was established that a reasonable yield function for slip rotations can be expressed as a quadratic form in terms of anti-symmetric parts of stress tensor and critical rotational stress. Therefore, the generalized minimum work method of obtaining the solution of lattice rotations was considered to correspond to the optimizing technique for a problem with a set of linear and non-linear constraints. A mathematical examination of this problem led to a conclusion that the optimum solution is unique and consequently the lattice rotation can be uniquely predicted.
A computer program, which is able to determine uniquely the orientation change of grains undergoing constrainted deformation for slip on {111}⟨110⟩ systems, was developed employing a computer technique of non-linear optimization problem (SUMT by Created Response Surface Technique). The developed computer method was applied to predict the path of rotation of grains during axisymmetric flow in tension of FCC metals.View full abstractDownload PDF (539K) -
Kenji Morinaga, Yukio Suginohara, Tsutomu Yanagase1976 Volume 40 Issue 8 Pages 775-780
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInfrared absorption spectra of silicate glasses containing Fe2O3 have been measured in order to find out the effect of Fe2O3 on the structure of silicate anion. In binary systems RO·Fe2O3 and R2O·Fe2O3, the peak shifts of absorption spectra Fe3+-O2− were studied in terms of the oxygen coordination number of Fe3+.
The results indicate that the wave numbers of absorption peaks in Fe3+(oct.)-O2− and Fe3+ (tetr.)-O2− were about 580 cm−1 and 625∼660 cm−1, respectively. The oxygen coordination number of Fe3+ varied with the (RO, R2O)/Fe2O3 ratio and the basicity of RO, R2O·Fe3+ in octahedral sites was predominant for the acidic glasses. It was assumed that the oxygen coordination number of Fe3+ in silicate glasses varied with the basicity of silicate glasses, and Fe3+ (oct.) acted on silicate anion structure as a network modifier.View full abstractDownload PDF (502K) -
Joo Ishihara, Masaichi Nagai, Tomio Iizuka, Yasushi Ouchi1976 Volume 40 Issue 8 Pages 781-786
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe present study was undertaken to clarify the mechanism of chipping phenomenon frequently found on pressing punch, since no definite theory to describe the phenomenon has been established. The punches made of several different types of tool steel were used to stamp out sheets of mild steel and stainless steel. Blanking punches, after use, were examined by means of electron fractography and optical microscopy.
The results of observation were summarized as follows.
(1) When stamping out 18Cr-8Ni type stainless steel sheets, some of the metal from the sheets adhered to the side surface of the punch after several thousand blankings. As blanking continued, the metal fell off and adhered repeatedly, while a small pit was formed at the side surface of the punch.
(2) When blanking out mild steel sheets, wear was observed at the side surface of the punch after several thousands or more of blankings. And the carbides present at the surface of the tool steel fell off from the matrix and pits were formed.
(3) After pit formation, cracks appeared at the corner of the pits.
(4) When chipping occurred on a punch, the fractured surface was examined. As a result, fatigue fracture took place near the side surface of the punch and brittle fracture inside the punch.
(5) It was surmised that the working stress of blanking was concentrated at the pits formed on the side surfaces. From these observations, it was concluded that fatigue cracks started from the side surfaces of punches and brittle fracture propagated inwards.
The proposed mechanism of chip formation is in contrast to the conventional concept of simple cracks starting from the punches.View full abstractDownload PDF (1634K) -
Zen-ichiro Morita, Akio Kasama1976 Volume 40 Issue 8 Pages 787-795
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of a minute amount of dissolved oxygen below 0.02 at% on the surface tension of liquid copper has been measured by the sessile drop method at 1100, 1200, 1300 and 1400°C. Surface tension of copper over the region of dilute oxygen concentrations decreased with increasing partial pressure of oxygen in the atmosphere, and this tendency was remarkable at lower temperatures. The temperature coefficient of surface tension of liquid copper changed from negative to positive with increasing oxygen content. It can therefore be presumed that the results reported by Krause and by Pugachevich et al., in which the surface tension of liquid copper increasing with increasing temperature may be caused by the presence of a slight amount of oxygen in the atmosphere or specimen. Furthermore, it was found that an approximate linear relationship existed between the surface tension of liquid copper and the amount of adsorved oxygen on the liquid copper surface.View full abstractDownload PDF (764K) -
Hideki Hagi, Shigeru Asano, Rikuro Otsuka1976 Volume 40 Issue 8 Pages 796-801
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSNickel metal cathodically charged with hydrogen in sulfuric acid solution was investigated by means of X-ray diffraction and electrochemical methods. It was found that nickel hydride of the face-centered cubic structure with a lattice constant about 6% larger than that of nickel is formed in the surface of nickel charged with hydrogen. In sulfuric acid solution, hydrogen-charged nickel gave the anodic polarization curve with a new peak at about −100 mV vs SCE which does not appear in that of pure nickel. The new peak grew up with the hydrogen charging time, that is, with the amount of the hydride which was indicated by the intensity of its X-ray diffraction lines. The peak was attributed to the oxidation of hydrogen in nickel. The hydride was not stable in air and decomposed gradually at room temperature with hydrogen evolution. Hydrogen evolution was followed initially only by the shrinkage of the hydride lattice from a=3.74 Å to 3.71 Å, and the amount of the hydride began to decrease after about 70% of hydrogen had been evolved. From this fact it was revealed that the hydride exists over a wide range of composition. The range was estimated to be from NiH0.2 to NiH0.7. The activation energy of the decomposition of the hydride was determined to be 11∼14 kcal/mol from the lattice shrinkage and 14∼20 kcal/mol from the amount decreased.View full abstractDownload PDF (641K) -
Masanobu Ohmori, Yasuhide Sakakibara, Kohji Kaneko, Yoshitoyo Yoshinag ...1976 Volume 40 Issue 8 Pages 802-807
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to correlate experimentally the temperature- and strain rate-dependence of the intermediate temperature embrittlement of copper with its grain boundary deformation behaviours and fracture modes, OFHC copper specimens were annealed to have grain diameters of 20, 80 and 180 μ and then tested in tension in vacuum. The testing temperatures and strain rates ranged from room temperature to 700°C and from 2.3×10−3 to 120/sec, respectively. Findings in the present experiments are summarized as follows. (1) The intermediate temperature embrittlement of copper occurred remarkably in vacuum as well as in air. (2) The ductility at a given temperature and strain rate decreased sharply with grain diameters between 20 and 80 μ, beyond which the ductility remained almost unchanged. (3) In a temperature range in which the embrittlement occurred, the fracture of the specimen stretched at a low strain rate (\simeq10−3/sec) was the intergranular one accompanied by microvoid coalescence, the mode of which was changd with temperature. At an intermediate deformation speed (\simeq10−1/sec), the specimen was fractured finally by a ductile fracture of matrices among large cavities originating from local separations of grain boundaries. The mode of fracture of the matrices was also changed with temperature. The fracture of the specimen tested at a very high speed (\simeq102/sec) was the transgranular one accompanied by microvoid coalescence.View full abstractDownload PDF (1408K) -
Kumayasu Yoshii, Yoshimasa Obora, Hideaki Kawabe, Tomoharu Yamada1976 Volume 40 Issue 8 Pages 807-812
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSheet specimens of high and commercial purity aluminum polycrystals were deformed in tension until the specimens necked and fractured. Strains of the necked region in the directions of the tensile axis, width and thickness of a specimen, that is, εl, εw and εt, respectively, were measured from the appearance of the orthogonal grids scribed on the specimen surface. Dislocation structures in the necked region, strains of which were known, were also observed by means of electron microscope. The results are as follows:
(1) Specimens of high purity aluminum ruptured after 100% reduction in area, and the measured values of εl and εw in the grids containing the fractured part were about 300% and 30%, respectively. In the case of commercial purity aluminum the reduction in area was about 65%, and εl and εw were about one-half of those in high purity aluminum.
(2) Pronounced cross-slips were observed on the surface of the necked region. Cell structures were formed in the regions of uniform deformation, necking and rupture. In the area unaffected by necking, cell structures were equi-axed having an average size of 3.5 μ for high purity and 3 μ for commercial purity aluminum, whereas in the necked region and the fractured part the cell structures were smaller in size and the dislocation densities in the cells increased.
(3) The cell size decreased linearly with increaseing reduction in area. Thus cell structures formed before the fracture has occurred seem to have a size of less than 2 μ for high purity and 1.5 μ for commercial purity aluminum. It could be imagined that fine cell structures in the necked regions result from the increase of cross-slips under two-dimensional stresses.View full abstractDownload PDF (771K) -
Hakaru Masumoto, Kiyoshi Watanabe, Shigehiro Ohnuma1976 Volume 40 Issue 8 Pages 812-816
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCrystal structures and magnetic properties of Ir-Mn-Sb alloys were studied through X-ray and magnetic analyses. It has been found that the intermetallic compounds of the Clb-type structure exsist in the IrMn1+xSb system and forms a solid solution in the composition range of x=0.5∼0.8. IrMn1.5Sb and IrMn1.8Sb alloys of the Clb-type have lattice parameters of about 6.154 and 6.141 Å at room temperature, magnetic moments nB of 2.6 and 2.1 μB per Mn atom at absolute zero, and Curie temperatures Tc of 278 and 258 K, respectively. From the temperature dependence of reciprocal magnetic susceptibility 1⁄χg, these Clb-type alloys are expected to change from the ferromagnetism to the ferrimagnetism with increasing Mn content.View full abstractDownload PDF (387K) -
Hakaru Masumoto, Masakatsu Hinai, Y\={u}etsu Murakami1976 Volume 40 Issue 8 Pages 817-820
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSNi-Fe-Nb-W alloys were heated in hydrogen atmosphere at 1150°C for 3 hr and then cooled at vairous rates from a temperature above order-disorder transformation points. The highest values of 109000 in initial permeability and 463000 in maximum permeability are obtained for the alloy of 79.45%Ni, 11.54%Fe, 8.51%Nb and 0.50%W when cooled at the rate of 240 and 300°C/hr, respectively. The electrical resistivity of the alloy cooled at 240°C/hr is 74.6 μΩ-cm, its Vickers Hardness being 202. These high permeability Ni-Fe-Nb-W alloys show very low saturation magnetostriction constants.View full abstractDownload PDF (309K) -
Kazuyoshi Kamachi, Mutsumi Touge1976 Volume 40 Issue 8 Pages 821-827
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is well known that stainless steels which are austenitic at room temperature are transformed to ε and α′ phases by cold work or quench into a low temperature below the Ms point. On the other hand, the same phenomenon of transformation occurs in austenitic stainless steels by cathodical hydrogen charge as well as cold work.
To consider the mechanism of hydrogen induced phase transformation and the induced phases, X-ray diffraction patterns taken from hydrogen charged specimens were compared with those of the cold-worked and quenched specimens. It was made clear experimentally that the hydrogen induced phases of ε and α′ are essentially the same as the strain induced phases, but they take a different process in their induction, that is, γ→ε′→(ε+α′). The ε′ phase is a c.p.h. structure having slightly different lattice constants from ε, which is considered to be a sort of transition phase containing supersaturated hydrogen. An Fe-Ni alloy was used to follow the hydrogen induced phase transformation, and the hydrogen induced phase transformation in this alloy was also ascertained.View full abstractDownload PDF (783K) -
Hiroshi Kobayashi, Jiro Jizaimaru1976 Volume 40 Issue 8 Pages 828-833
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPrecipitation characteristics of Nb(C, N) in the austenite phase of low carbon-high manganese steels have been investigated kinetically.
It has been demonstrated that the precipitation behavior in austenite can be followed by a two-step aging treatment: Steels which had been solution-treated at 1250°C were precipitation-treated at temperature between 840 and 1020°C for various periods and then quenched to 540°C in ferrite region and subsequently aged for 900 min.
Age-hardenability of ferrite is reduced by the first step precipitation-treatment in austenite because of the decrease of the driving force for precipitation in ferrite. It has been recognized that the precipitation of Nb(C, N) in austenite ca nbe estimated by such reduced age-hardenability of ferrite.
The rate of precipitation of Nb(C, N) in austenite increases with Nb content and is largest at about 980°C because the time to reach a certain fraction of Nb(C, N) is shortest at this temperature when plotted against the precipitation temperature.
Precipitation of Nb(C, N) is rate-controlled by the diffusion of Nb in austenite but not by that of C or N.
The rate of precipitation Nb(C, N) is accelerated markedly by hot working in austenite and the acceleration is larger at lower hot working temperature. But the precipitation of Nb(C, N) does not take place during hot working at any temperature investigated.View full abstractDownload PDF (464K) -
Ken-ichi Takimoto, Isamu Taguchi, Ry\={u}tar\={o} Matsumoto1976 Volume 40 Issue 8 Pages 834-838
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPotentiostatic quantitative extraction of cementite and manganese sulfide in steel has been studied in order to establish a new method with a non-aqueous electrolyte instead of the conventional method using an aqueous electrolyte. As the non-aqueous electrolyte, 5% triethanolamine-1%LiCl-methylalcohol, 10% acetylacetone-1%LiCl-methylalcohol, 5% triethanol-amine-1% tetramethylammoniumchloride-methylalcohol, and 10% acetylacetone-1% tetramethyl-ammoniumchloride-methylalcohol were studied. Chemical stability of the extracted precipitates, potential-current curves of the steel samples and the pontential dependence of extraction ratio obtained by use of the non-aqueous electrolytes are compared with those when using aqueous 5% sodium citrate-1.2% potassium bromide (pH 5). Unstable precipitates such as cementite and manganese sulfide were found to be chemically stable in the non-aqueous electrolyte and to be quantitatively extracted. 10% acetylacetone-1% tetramethylammoniumchloride-methylalcohol was recommended as the non-aqueous electrolyte because of its high accuracy and reproducibility of the analytical results.View full abstractDownload PDF (450K) -
Akinori Matsuda, Tadao Takeoka, Koichi Nakajima1976 Volume 40 Issue 8 Pages 839-843
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMeasurements were made of mechanical properties of iron-20% nickel alloys having the (α+γ) microduplex structure formed during the aging process. The results obtained are summarized as follows:
(1) Austenite formed during aging increased with aging temperature. The amount of austenite became maximum at 530°C, and austenite and ferrite phases appeared in alternating plate-like layers.
(2) Toughness of the alloys with the (α+γ) microduplex structure decreased with increase in tensile testing temperature, and showed severe brittle behavior at high temperatures. The specimens were fractured along the original austenite grain boundaries. In the temperature range from room temperature to liquid nitrogen temperature, however, the specimens with the two-phase structure showed considerably higher toughness and work hardening than those with a single phase structure. These results were associated with the γ→α′ transformation during the deformation.
(3) In the initial stages of plastic deformation of the microduplex specimens, dislocations were mainly produced in the γ phase, leading to inhomogeneous deformation of the specimens. Dislocations were piled up toward the (α−γ) interface with deformation.View full abstractDownload PDF (868K) -
Shinji Tsuji1976 Volume 40 Issue 8 Pages 844-851
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThree different αFe-βTi couples were annealed in the temperature range between 850 and 1050°C. Resulting concentration distributions in the αFe and βTi phases were determined by electron probe microanalysis, and layer thicknesses of the Fe2Ti and FeTi phases formed in the diffusion zone were measured.
Where any two adjacent phases in couple, j and k, differ from each other in partial molal volumes \barVi of the diffusing components, a method for determining the interdiffusion coefficients has been established by adding some complementary steps to the previously reported one. The interdiffusion coefficients in the αFe, Fe2Ti, FeTi and βTi phases were calculated by the above method.
When it was assumed that the relation \barVij=\barVik was satisfied for all the phases in the couples, interdiffusion coefficients for the Fe2Ti and FeTi phases calculated from Kidson’s equation were consistent with those obtained by the previous method, respectively.
Interdiffusion coefficient for an intermediate phase has often been determined from either Kidson’s equation or Heumann’s equation under the assumption, dc⁄dx=const. regardless of x in the intermediate phase layer. It is demonstrated in this study that validity of the above assumption may be restricted by moving behavior of the phase interfaces.View full abstractDownload PDF (735K) -
Toyojiro Isano, Michinori Takano, Saburo Shimodaira1976 Volume 40 Issue 8 Pages 851-858
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStress-corrosion cracking behaviors of Al-Zn-Mg alloys in 3%NaCl aqueous solutions (room temperature to 70°C) with or without oxidizers were examined by means of optical and electron microscopy, and the mechanisms of the stress-corrosion cracking were discussed.
The results obtained from a constant total strain test for Al-2.64%Mg-4.63%Zn alloy in 3%NaCl+3%K2Cr2O7+3.6%CrO3 aqueous solution (70°C) showed that cracks initiated at the edges of three adjacent grains at a relatively low applied stress, and that cracks also initiated at both sites of the three adjacent grains and the normal grain boundaries which have a large angle against the stress direction at a high applied stress. The precipitates at grain boundaries accelerated an intergranular cracking, and even if the condition wherein the precipitates were not observed in grain boundaries through a transmission electron microscope, the intergranular cracking could occur. Although the stress-corrosion cracking propagated predominantly along grain boundaries, some transgranular cracks, which appeared to be mechanically ductile fracture, were also observed in the fractographs. The effects of Cl− ion concentration, pH, oxidizers and temperature on stress-corrosion cracking were also examined, and it was found that the susceptibility to stress-corrosion cracking was strongly affected by the above factors. The results of stress-corrosion cracking tests obtained from a constant total strain method, a constant load method and a constant strain rate method did not show good coincidence.View full abstractDownload PDF (1469K) -
Kimio Itagaki, Akira Yazawa1976 Volume 40 Issue 8 Pages 859-865
Published: 1976
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe measurements of the thermodynamic quantities for cadmium chloride-lead chloride and lead chloride-zinc chloride binary melts were carried out by quantitative thermal analysis in the heating process. A double adiabatic walls calorimeter was used as the experimental apparatus.
Some theoretical considerations were made to obtain the precise data for the nonmetallic materials such as salts and oxides of which the coefficients of temperature propagation are very low. It was clarified that the influences of some factors such as the size of the specimen, the surface area for heat transfer and the heating velocity of the specimen were decisive, and proper experimental conditions were established.
The free energies of mixing, ΔGmix, of cadmium chloride-lead chloride binary melts present simple behavior which is somewhat negative as compared to the ideal mixing. On the other hand, the lead chloride-zinc chloride binary melts show an anomaly in that ΔGmix is considerably less negative in the concentration range of zinc chloride above NZnCl2=0.5, though it presents a very small deviation from ideal mixing in the low concentration range of zinc chloride. This corresponds to the observed anomalies in the other physical properties of the melts.View full abstractDownload PDF (577K)
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