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Volume 38, Issue 11
Displaying 1-15 of 15 articles from this issue
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Yasutoshi Saito, Yutaka Shinata, Kyoko Yokota, Koutaro Miura1974 Volume 38 Issue 11 Pages 997-1005
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe thermal decomposition of lanthanum oxalate decahydrate, La2(C2O4)3·10H2O, was studied by thermogravimetry (TG), differential thermal analysis (DTA) and effuluent gas analysis (EGA). The products at various stages of decomposition were characterized by infra-red absorption spectroscopy, X-ray diffraction analysis, surface area measurement and electron microscopy.
The following five steps were expected to take place during the thermal decomposition of lanthanum oxalate decahydrate: decahydrate→monohydrate→anhydrate→monoxydicarbonate→dioxymono-carbonate→oxide. The decomposition of anhydrous oxalate was accompanied by the deposition of finely divided carbon particles formed by the disproportionation of primarily evolved carbon monoxide, which was remarkable during the decomposition of monoxydicarbonate.
The curves of variations in surface area with temperature for the decomposition products at the various stages showed two maxima, respectively; the first was due to the decomposition of anhydrous oxalate, and the second to the decomposition of monoxydicarbonate.
In electron microscopy, the oxalate particles were rectangular platelet of 10∼30 μ, and the oxide appeared as the skeleton particles of the original oxalate.View full abstractDownload PDF (823K) -
Yasutoshi Saito, Yutaka Shinata, Yoshiki Hasegawa1974 Volume 38 Issue 11 Pages 1006-1013
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSOptically stimulated exoelectron emission (OSEE) and thermally stimulated exoelectron emission (TSEE) from aluminum surfaces after abrasion and X-ray irradiation in air were measured using gas-flow type G-M counters equipped with a light illumination system and a heating unit. Important factors investigated were temperature and wavelength in OSEE, and light illumination and elapse of time after abrasion in TSEE.
The decay of OSEE after abrasion was more rapid at higher temperatures in the range 25∼55°C, and at longer wavelengths in the range well beyond the photoelectric threshold of aluminum. The isothermal decay curve of OSEE 4 hr after abrasion was found to be approximately a sum of two exponential terms. Apparent activation energies obtained from each temperature dependence of the two terms were almost the same, and 4.8 kcal/mol and 2.9 kcal/mol under light illuminations of 3700 and 4200 Å, respectively. The decay of OSEE was considerably suppressed at liquid nitrogen temperature.
TSEE after abrasion was hardly observable in the absence of light illumination. When illumination was applied the intensity of TSEE decreased with time after abrasion. The TSEE curve after X-ray irradiation exhibited marked peaks at about 120 and 240°C, which were not affected by light illumination.View full abstractDownload PDF (683K) -
Hisashi Suzuki, Kozi Hayashi1974 Volume 38 Issue 11 Pages 1013-1019
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSObservations of microstructural defects (fracture origins) appearing on the transverse-ruptured surface of cemented carbide were carried out. The transverse-rupture strength (σm) of each specimen was studied in relation to the location and dimensions of the defects. WC-10%Co high carbon two-phase alloys with a mean grain size of about 1.7 μ and alloys containing small amounts of structural defects such as pores, anomalously large WC grains or binder-pools were vacuum-sintered and used as specimens.
Results obtained were as follows: (1) Three kinds of structural defects, i.e., pore, WC grain or binder-pool were mainly found to act as fracture origins; these defects were invariably observed near the center of a comparatively flat area of the radially fractured zone, the so-called white spot. (2) The σm is weakly correlated with the location or dimension (2a) of defects; the calculated external stresses (σd) operated at the defects at fracture, however, are strongly correlated with their dimensions. Thus, a linear relation was generally found between σd−1 and \sqrta. (3) Therefore, σm can be experessed by the equation, σm={830⁄(1+2\sqrta⁄8.5×10−3)}{t⁄(t−2Δt)}{l⁄(l−2Δl)}, where t and l are the thickness and span length of specimen, Δt and Δl are the distance to the fracture origin from the tension surface and the span-center, respectively. Thus, the distribution and the mean value of σm of a set of specimens could be evaluated, when the spacing and dimensions of defects were known. By means of decreasing defect size and increasing its spacing, the σm of cemented carbide would abruptly increase and the extrapolated value of σm became as high as about 800 kg/mm2. (4) In this respect, re-examination of the factors affecting the strength as well as the theory of strength in cemented carbides would be needed.View full abstractDownload PDF (757K) -
Toyoaki Eguchi, Shotaro Morozumi1974 Volume 38 Issue 11 Pages 1019-1025
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSolubility of hydrogen in molybdenum and its binary solid solution alloys containing titanium, zirconium, vanadium and niobium, respectively was measured in the temperature range between 600 and 1200°C under one atmosphere pressure of hydrogen gas.
The following results were obtained.
(1) Relative partial molar entropy Δ\barSXS and enthalpy Δ\barH for hydrogen solubility in molybdenum were obtained as Δ\barSXS=−15.8 cal/g-atom·deg and Δ\barH=9.51 kcal/g-atom respectively.
(2) The solubility increased with increase in the amount of each alloying element.
(3) The entropy of the alloys first decreased with increase in the alloying elements and became almost constant with a value of approximately −17.5 cal/g-atom·deg. Vibrational frequency of hydrogen atom calculated from Δ\barSXS values was 3.0×1013 sec−1 for molybdenum and 4.0×1013 sec−1 for the alloys.
(4) In Mo-Ti alloys, and Mo-V and Mo-Nb alloys containing more than about 10 at% of each alloying element, the enthalpy decreased monotonically with increase in electron/atom ratio.
(5) Values of Δ\barSXS and ΔH in Mo-V and Mo-Nb alloys were minimum at the composition of about 3 at% of these alloying elements. Variation of these values seemed to be related to the electronic specific heat coefficient of alloys.
(6) In Mo-Zr alloys, the lattice strain induced by alloying also affected the solubility.View full abstractDownload PDF (536K) -
Toyoaki Eguchi, Shotaro Morozumi1974 Volume 38 Issue 11 Pages 1025-1030
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSolubility of hydrogen in vanadium and its binary alloys containing titanium, chromium, iron and cobalt, respectively was measured in the temperature range between 600 and 1200°C under one atmosphere pressure of hydrogen gas. The influence of alloying elements on the solubility, and the correlation between hydrogen solubility and electronic structure of alloys were discussed.
The following results were obtained:
(1) The solubility decreased with increase in amount of each alloying element, with the exception of titanium.
(2) The lattice strain induced by alloying did not affect the solubility.
(3) Relative partial molar entropy and enthalpy increased linearly with increase in electron/atom ratio from 4.9 to 5.4.
(4) Variation in entropy was correlated to that in the electronic specific heat coefficient of alloy.
(5) Variation in enthalpy was explained by that in density of state at the Fermi surface in the alloys.View full abstractDownload PDF (465K) -
F. Eiichi Fujita, Chiaki Shiga, Takeshi Moriya, Hiromitsu Ino1974 Volume 38 Issue 11 Pages 1030-1037
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMartensite of high carbon steel, formed by quenching from the γ phase region to −196°C and kept at that temperature, exhibits a component of the Fe57 Mössbauer spectrum which is not observed for ordinary martensite at room temperature. Precise analysis shows that the component arises from the iron atoms neighboring to the carbon atoms in the tetrahedral interstices in the martensite structure.
The values of the internal magnetic field, isomer shift, and electric quadrupole effect for the iron neighbors of the tetrahedral and octahedral interstitial carbon atoms are discussed in terms of the covalent bonding expected between the carbon and surrounding iron atoms.
Analysis of the changes in the Mössbauer spectra during tempering shows that in the freshly formed martensite the carbon atoms occupy the octahedral and tetrahedral sites with nearly equal populations and the carbon atoms in the latter begin to move to the former by ageing below room temperature.View full abstractDownload PDF (701K) -
Chiaki Shiga, Masakatu Kimura, F. Eiichi Fujita1974 Volume 38 Issue 11 Pages 1037-1045
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFe57 Mössbauer spectra of the martensite of high carbon Fe-6%Ni alloy show that carbon atoms occupy not only the octahedral but also the tetrahedral interstics at low temperatures as well as in the case of plain high carbon steel. In the martensite freshly formed and kept below −80°C, both kinds of the interstitial sites are occupied with equal populations, and the carbon atoms begin to move from the tetrahedral to the octahedral sites by the ageing at room temperature and thorough movement is achieved at 80°C. The equal population occupancy cannot be explained by the direct transformation mechanism from fcc to bcc with lattice shears, dilatations and contractions, but by the mechanism through the intermediate phase either the hexagonal ε phase or the “6 layer shuffled structure” which we propose in this paper.View full abstractDownload PDF (760K) -
Asahi Kawashima, Koji Hashimoto, Saburo Shimodaira1974 Volume 38 Issue 11 Pages 1046-1050
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSRelation of hydrogen embrittlement of mild steel with hydrogen electrode reaction and hydrogen absorption in acidic hydrogen sulfide solutions at room temperature was studied by means of a constant strain rate method. From the current passed and the amount of hydrogen absorbed in mild steel during potentiostatic cathodic polarization, the hydrogen electrode reaction mechanism and the effect of hydrogen sulfide on the reaction have been elucidated. An expression has been derived which relates the amount of absorbed hydrogen QH to the fracture stress σf as follows, σf+KQH=constant. Consequently, the absorbed hydrogen contributes to hydrogen embrittlement of mild steel as the sum of applied stress and apparent stress arising from absorbed hydrogen. The failure will occur even at a very low applied stress if the amount of absorbed hydrogen may increase considerably. The activation energy for hydrogen embrittlement of mild steel under a corrosive environment was estimated as 8800 cal/mol.View full abstractDownload PDF (405K) -
Kiyoshi Kita, Masanori Kiyoshige, Kuniyasu Sakai1974 Volume 38 Issue 11 Pages 1050-1059
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the heat affected zone of welded joint of Ni-Cr-Mo alloy, it has been known that stress corrosion cracking occurred in hydrochloric acid solution and corrosion resistance is deteriorated. A laboratory investigation was conducted to study the relationship between the microstructure and the susceptibility of the welded joints of Ni-Cr-Mo alloy to stress corrosion cracking and corrosion resistance.
The susceptibility of solid solution treated Ni-Cr-Mo alloy to stress corrosion cracking was small, but the microstructure of this alloy was remarkably changed by heat treatment and consequently the heat affected zone of welded joints was susceptible to stress corrosion cracking and intergranular corrosion. These phenomena were attributed to the precipitation at the grainboundary and the microsegregation of minor elements such as carbon and silicon.View full abstractDownload PDF (1996K) -
Kohji Kawahara1974 Volume 38 Issue 11 Pages 1059-1065
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA study has been made to examine the effect of transformation on ridging phenomena occurring in ferritic stainless steels, using an iron-based alloy transformable.
The ridging occurred also in the alloy. In the specimens cold-rolled after having been directly cut from the ingot, the ridging occurrence was not suppressed only by the heat treatment for recrystallization. But it was suppressed by the treatment for transformation. The condition for the suppression did not depend on the type of the transformation, such as martensitic. In the specimens cold-rolled after the transformations, although the ridging appeared, its size was found to be smaller than that without the transformation. On the other hand, the variations resulting from the transformation, such as grain refining, strengthening of matrix, and change in the textures by various processes, were considered not to relate directly to the mechanism of suppression for the ridging occurrence.
From these results, the effect of the transformation on the suppression for the ridging phenomena was concluded as follows. By transforming, the elongated grains formed during rolling, some of which may behave as a single crystal under straining, are divided into much more fine grains with various orientations, and thus the orientational rotation of the elongated grains becomes difficult to develop.View full abstractDownload PDF (894K) -
Kenzi Morinaga, Tsuneo Ito, Yukio Suginohara, Tsutomu Yanagase1974 Volume 38 Issue 11 Pages 1065-1070
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTiO2 addition to the CaO-SiO2 system was studied by measuring the density of melts and infrared absorption spectra of quenched glasses. The results of measuring the infrared absorption spectra indicate that the TiO2 present in the CaO-SiO2 system gives almost no effect upon the structure of silicate anion and acts as an innert diluent. The density of melts tends to increase linearly with increasing TiO2 content when CaO/SiO2 is constant. The molar volume and the packing ratio were calculated from the density data. Ti ions may be considered to hold both four and six co-ordination for oxygen ion, depending upon the ratio CaO:SiO2 in the melts. The behavior of the TiO2 in CaO-SiO2 system was discussed in terms of change of the ratio Ti4+(tetra.)/Ti4+(octa.).View full abstractDownload PDF (488K) -
Nobuo Matsuno, Hiroshi Oikawa, Seiichi Karashima1974 Volume 38 Issue 11 Pages 1071-1076
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSubstructures developed during steady-state creep in polycrystalline Al-Mg alloys containing 0.52 to 5.54 at% magnesium were observed in the temperature range 573 to 673 K and the stress range 14.7 to 68.6 MPa.
Under the condition where n\simeq3 (n: the applied-stress exponent of steady-state creep rates) long, curved dislocations were distributed homogeneously in the greater part of the grain interior. Sub-boundaries were observed only in the vicinity of grain boundaries. This region became wider as the concentration of magnesium decreased. In alloys of high concentration of magnesium general feature of dislocation distribution was independent of the applied stress, σc, though the dislocation density, ρ (m−2), depended greatly on σc (MPa); for example, ρ=1.45×1010σc1.62 in Al-5.54 at%Mg alloy at 573 K.
In alloys of low concentration of magnesium and/or under high stress sub-boundaries were formed all over the grains. The creep condition under which the above fact was observed was the same as that under which n became obviously larger than 3 and m* became larger than unity (m*: the effective-stress exponent of dislocation velocity). The dislocation distribution within sub-grains was similar to that in alloys of high concentration of magnesium. The density of dislocations which were not associated with sub-boundaries was almost independent of the concentration of magnesium.View full abstractDownload PDF (1561K) -
Kichinosuke Hirokawa1974 Volume 38 Issue 11 Pages 1077-1082
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSRelative inelastic scattering cross section for the photoelectron spectroscopy were obtained by using binary alloys with homogeneous phase and comparatively clean surface. In this experiment it was not necessary theoretically to employ the clean surface. To obtain the relative cross section the formula of
(This article is not displayable. Please see full text pdf.)
\ oindentwas introduced, where NAjA is the intensity of electron from the level of jA in element A, CA is the concentration (weight fraction) of element A, εAjA is the inelastic cross section of electron from jA level through element A, and k is a constant. Using the binary alloy of copper-nickel and copper-gold, the relative inelastic cross section was obtained by the curve fitting:
(This article is not displayable. Please see full text pdf.)
\ oindentConsidering the obtained values and the relation between the escape depth (1⁄ε) and the kinetic energy of electrons, the so-called universal curve was confirmed to be effective for the low energy electron of kinetic energy range of 50∼2000 eV.View full abstractDownload PDF (459K) -
Kazuaki Fukamichi, Hideo Saito1974 Volume 38 Issue 11 Pages 1083-1084
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (123K) -
1974 Volume 38 Issue 11 Pages 1084
Published: 1974
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPlease see pdf. Wrong:[in Japanese], [in Japanese] Right:[in Japanese], [in Japanese]View full abstractDownload PDF (85K)
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