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Volume 51, Issue 7
Displaying 1-17 of 17 articles from this issue
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Hideki Hagi, Yasunori Hayashi1987 Volume 51 Issue 7 Pages 591-598
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPermeation rates of tritium and hydrogen through iron were measured by the electrochemical method in which an aqueous solution containing 3.7×1012 Bq/m3 tritium was used as a cathodic electrolyte. Tritium and hydrogen were introduced from one side of a specimen by cathodic polarization with a constant current density, while at the other side of the specimen the permeated tritium and hydrogen were extracted by potentiostatical ionization. Nearly all of the potentiostatic current on the extraction side is produced by the ionization of hydrogen, because the concentration of tritium in the cathodic electrolyte is very small. The amount of permeated hydrogen was obtained by integrating the potentiostatic current, and that of permeated tritium was determined by measuring the radioactivity of the electrolyte sampled from the anodic side. The separation factor for permeation obtained under steady state conditions (the ratio of permeation rates of hydrogen to tritium divided by the ratio of the concentration of hydrogen to tritium in the cathodic electrolyte) is 12 at 288 K. This value is independent of cathodic current density. Diffusion coefficients of tritium (DT) and hydrogen (DH) in iron were determined from the tritium and hydrogen permeation by using time lag technique. For annealed iron at 286 K, DT=9×10−10 m2/s and DH=4×10−9 m2/s, and for 9% cold-worked iron at 284 K, DT=3×10−10 m2/s and DH=4×10−10 m2/s.View full abstractDownload PDF (1042K) -
Shin-ya Komatsu, Shigeru Kuribayashi, Takashi Sugimoto, Koichi Sugimot ...1987 Volume 51 Issue 7 Pages 599-607
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of heat treatments on martensitic transformation temperature (Ms) of Cu-Zn-Al and Cu-Al-Ni-Ti shape memory alloys having two different compositions respectively were investigated by electrical resistivity measurement, X-ray diffraction and optical microscopy. Annealing or partial solution treatment were carried out at temperatures below the β transition temperature (Tβ) and aging at temperatures below the eutectoid temperature, respectively.
By annealing at temperatures below Tβ, the Ms was either lowered in Cu-Zn-Al alloys or raised in Cu-Al-Ni-Ti alloys from that after complete solution treatment above Tβ. This behavior was explained by the increase or decrease of solute concentration in the β solid solution due to the precipitation of α or γ2 phase, respectively. The same tendency of the Ms change was also observed by aging at temperatures up to 673K. A Cu-27.7 mass%Zn-4.32 mass%Al alloy showed, in the initial stage of aging, reversible and rapid change in Ms wth aging temperature, which was attributed to a change in the ordered state, and after a prolonged aging, showed an irreversible decrease in Ms with aging phenomena accompanying long range diffusion. In Cu-Al-Ni-Ti alloys, the Ms increase by the change in the ordered state was slower than that of Cu-Zn-Al alloys. Namely, Cu-Al-Ni-Ti alloys showed a better thermal stability than that of Cu-Zn-Al alloys up to higher temperatures for longer periods of aging. Ms changes by precipitation of α or γ2 phase by aging were especially remarkable in alloys of composition remote from eutectoid point. A Cu-14.9 mass%Al-3.26 mass%Ni-0.45 mass%Ti alloy showed an increase of Ms due to precipitation of the γ2 phase by more than 200 K.View full abstractDownload PDF (1863K) -
Shouichi Ochiai, Seiji Miura, Yoshinao Mishima, Tomoo Suzuki1987 Volume 51 Issue 7 Pages 608-615
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA Ni3(Al, Ti) single crystal with orientation near [001] showed a new type of yielding accompanied by a remarkable yield drop and a successive steady state deformation when it was deformed under a certain test condition at elevated temperatures. The characteristics of this high temperature yielding phenomenon (H.T.Y.) were studied by compression tests at various temperatures from 77 to 1273 K with strain rates varying from 1.4×10−2 to 1.4×10−5 s−1.
Results obtained are as follows: (1) {111} slip operates predominantly at higher temperatures beyond the maximum in flow stress under the conditions where the H.T.Y. occurs. (2) The state equation of this high temperature steady state deformation can be expressed as the same type as that of steady state creep. The value of the stress exponent is about 3 and the activation energy is nearly equal to that for diffusion. This suggests that {111} slip deformation is controlled by the viscous motion of dislocations. (3) In the H.T.Y., the stress drop was not so rapid and a Lüders band propagation was not observed. These characteristics are consistent with those of the Johnston type, so that the appreciable yield drop is considered to be due to the increase of mobile dislocation density during plastic deformation. (4) Using state equation obtained, the condition for the development of the H.T.Y. can be derived, by which H.T.Y. is expected only for single crystals having near ⟨100⟩ orientations. This prediction may well accounts for the experimental result.View full abstractDownload PDF (1465K) -
Katuo Saitou, Yoshikazu Hosoi, Yasuo Otoguro1987 Volume 51 Issue 7 Pages 616-623
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESS7075-Al alloy has been tensile tested in order to investigate the difference of discontinuous deformation models, and the rate process of discontinuous deformation by means of activation energy, and individual values of m and β. Tensile tests have been performed in the temperature range mainly from 243 to 408 K, in the strain rate range from 1.67×10−5 to 6.67×10−3 s−1. Changes in mechanical properties with or without discontinuous deformation are described. The main results obtained are as follows:
(1) Discontinuous deformation behavior can be divided into regions I and II, by the appearance of load-elongation curve and the strain rate dependence of critical strain, positive in region I and negative in region II.
(2) Values of m and β are positive in region I, whereas in region II, the value of β is positive but m is negative.
(3) The activation energy is 49.3±2.5 kJ/mol in region I and 108.0±1.0 kJ/mol in region II. The rate process of the former is the vacancy-solute complex, and that of the latter appeared to be self diffusion of solute.
(4) A distinction of the models cannot be made by the calculation methods of activation energy.View full abstractDownload PDF (1202K) -
Xu-yun Ye, Shiro Haruyama1987 Volume 51 Issue 7 Pages 624-629
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCarburization of iron having different surface characteristics has been studied under CO-N2 atmospheres at 1173∼1203 K by using an automatic microbalance. The initial rate of carburization of shaved or ground iron specimen was about two times larger than that of cold-rolled specimen. The higher the purity of iron, the faster the initial rate of carburization. The initial rate of the cold-rolled pure iron as shaved was eight times larger than that of cold-rolled commercial iron. Existence of catalyst such as platinum on surface was effective for increasing the rate of carburization. The initial rate of the cold-rolled pure iron as shaved and wound with platinum wire under 34.4%CO-N2 atmosphere was approximately equal to that of cold-rolled pure iron under 81.3%CO-N2 atmosphere. The results are discussed on the basis of a kinetic equation that was derived by solving the Fick’s diffusion equation in the presence of surface reaction.View full abstractDownload PDF (889K) -
Kiho Kim, Yuzuru Sato, Kazuyoshi Shimakage, Tatsuhiko Ejima1987 Volume 51 Issue 7 Pages 630-636
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDensities of LaCl3-alkali chlorides binary melts have been measured by the manometric method over the range of their liquidus temperatures to about 1200 K. The results obtained are summarized as follows:
Density measured decreases with an increase in the content of alkali chloride for all the binary melts. Composition dependence of density shows a non-linear relation and the densities of mixtures at arbitrary compositions do not change in the order of the radius of alkali cation. Molar volume increases with an increase in the radius of alkali cation in the entire range of composition for all the binary melts. The molar volume of all the binary melt shows positive deviations from the additivity except the melt containing LiCl. The deviations become larger as the radius of alkali cation increases, and show a maximum at 50-60 mol% alkali chloride. Partial molar volumes of LaCl3 in each of the binary melts increase with increasing content of alkali chloride in the range of more than 40-50 mol% alkali chloride except the melt containing LiCl, and this tendency becomes stronger in the order of cationic radius. Expansion coefficient increases monotonically with increasing content of alkali chloride for all the binary melts and the value becomes larger in the order of cationic radius. It is found that the complex ions of LaCl4− and LaCl63− are co-existing in the melt containing LaCl3.View full abstractDownload PDF (1031K) -
Katsumi Mochizuki, Katashi Masumoto1987 Volume 51 Issue 7 Pages 637-644
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAttention is recently paid to the new materials for tunable laser diodes, lasing at the wavelength from 2 to 4 μm. The laser diodes are expected as the light source for optical communications in the next generation and also as the real-time IR-photospectrometer for detecting quickly and exactly the kind and the concentration of hydrocarbon pollutants in air such as methane and ethane.
Multinary solid solution semiconductors such as ternary (Pb1−xCdx)S1−y and quaternary (Pb1−xCdx) (S1−zSez)1−y are best suited for the above purposes. To realize the continuous laser emission of tunable laser diodes near room temperature, it is necessary that the structure of the diode is a double-heterojunction with a matched lattice parameter and the composition (x, z) of each layer is controlled to a high degree.
For this purpose, simultaneous control of the composition (x, z) and the deviation y from stoichiometry is indispensable for each constituent layer.
In this study, a new method for simultaneously controlling the composition x and the deviation y from stoichiometry was proposed for the (Pb1−xCdx)S1−y solid solution. That is, the activities of sulfur (PS2) and CdS (aCdS) were controlled independently in the heat-treatment process of the solid solution by providing the respective reservoir chambers in the heat-treatment tube.
As a result, it was found that the composition x of the solid solution is seriously effected by the cadmium partial pressures (PCd) dissociated from CdS. From this fact, it was suggested that the deviation y from stoichiometry could also be controlled simultaneously by regulating PS2, keeping PCd to a specific value corresponding to the target composition x.
Based on this principle, the diagrams of P(PCd)-x and P(PS2)-T in composition x=0.20 were obtained successfully for this solid solution.
In conclusion, the exploited method is applicable to a simultaneous control of other ternary or quaternary solid solutions involving two metallic components.View full abstractDownload PDF (1177K) -
Hiroshi Ohmori, Junji Shibata, Makoto Sano, Sanji Nishimura1987 Volume 51 Issue 7 Pages 645-650
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of additive agents on the extraction Pr and Nd was investigated by using Versatic Acid 10 as an extractant. Tri-octyl phosphine oxide(TOPO), 2-ethylhexanal oxime (EHO), di-hexyl sulfoxide(DHSO), di-hexyl sulfide(DHS), bis-2-ethylhexyl acetamide (BEHAA), TBP, LIX 63 and Alamin 308 were used as additives. The mechanism of Pr extraction was examined and the effect of diluent on the extraction was also studied for the Versatic Acid 10/EHO system.
The extraction of Pr and Nd decreased by the use of additives except TOPO and LIX 63 owing to an interaction between Versatic Acid 10 and additives in the organic phase. Although the extraction decreased by the addition of EHO, BEHAA and DHSO, the separation factor of Pr and Nd was promoted due to a synergistic effect. The separation factors were 1.86, 1.83 and 1.50 for Versatic Acid 10/EHO, Versatic Acid 10/BEHAA and Versattc Acid 10/DHSO systems, respectively, instead of 1.22 for the extraction with Versatic Acid 10. The excess addition of EHO did not cause an increase in the separation factor. For the Versatic Acid 10/EHO system, the extracted species of Pr was found to be PrR3·3HR·EHO·H2O and the extraction equilibrium was expressed as
(This article is not displayable. Please see full text pdf.)
\ oindentwhere H2R2 and HR were the dimeric and monomeric forms of Versatic Acid 10. The diluent affected the extraction and separation factor of Pr and Nd. The extraction decreased by the use of diluents of a high dielectric constant, while the separation factor increased with an increase in the dielectric constant.View full abstractDownload PDF (835K) -
Masahiro Susa, Kazuhiro Nagata, Kazuhiro S. Goto1987 Volume 51 Issue 7 Pages 651-658
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA new simultaneous measurement method of thermal conductivity, thermal diffusivity, and specific heat for oxides at high temperature has been proposed with the use of hot strip.
The principle of this measurement is based on the two solutions of the Fourier’s partial differential equation solved under the different conditions of time. The response curve of temperature-increase obtained by a long time measurement is proportional to the logarithm of time. The slope of this straight line gives thermal conductivity (λ). On the other hand, the response curve by short time measurement is proportional to the square root of time. The slope of this straight line and the value of thermal conductivity offer thermal diffusivity (κ) and specific heat (Cp), by virtue of ρCp=λ⁄κ (ρ: density).
With the use of this method, thermal conductivity, thermal diffusivity, and specific heat of 30Na2O-70SiO2 slag have been measured over the wide temperature range of 300 to 1500 K. The thermal conductivity is in good agreement with that by the hot wire method. The thermal diffusivity is nearly constant at low temperatures but decreases with increasing temperature. The specific heat increases with increasing temperature but the absolute values are 1.1-1.2 times larger than those by the laser-flash method.
The hot strip method can be expected to permit a simultaneous measurement of thermal conductivity, thermal diffusivity, and specific heat at high temperatures for various oxides.View full abstractDownload PDF (1075K) -
Won Sub Chung, Takeaki Murayama, Yoichi Ono1987 Volume 51 Issue 7 Pages 659-665
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe reduction equilibrium relations between iron, iron oxides (FexO, Fe3O4) and CO-CO2 gas mixtures were measured using the following cell:
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The composition of the CO-CO2 gas mixtures in the reference electrode was changed so that the electromotive force became zero. The gas compositions were assumed to be the equilibrium gas composition.
The results obtained were as follows:
(This article is not displayable. Please see full text pdf.)
The standard Gibbs free energy of the reaction CO(g)+(1⁄2)O2(g)=CO2(g) was measured using air and Ni, NiO mixtures as a standard electrode. It was also calculated from the oxygen potential of iron oxides and the reduction equilibria of iron oxides with CO-CO2 gas mixtures which were measured in this experiment. Both results were in good agreement with each other. Results obtained were as follows;
(This article is not displayable. Please see full text pdf.)View full abstractDownload PDF (1033K) -
Minhui Zheng, Zensaku Kozuka1987 Volume 51 Issue 7 Pages 666-672
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe activities of indium in the binary and the ternary alloys were meaured by the EMF method using zirconia solid electrolyte over the temperature range of 873-1073 K. The activities of antimony in the binary alloys were calculated by using the Gibbs-Duhem equation. The activity values in the binary alloys are in close agreement with the results by Hoshino et al.
From the activities of indium in the five pseudobinary systems of fixed molar fraction ratio NPb⁄NSb, the excess molar free energies of the liquid ternary alloys were calculated by means of Darken’s method. The values are negative in almost all compositions except those near the In-Pb side and become negatively larger as the concentration of lead decreases. The activities of the other two elements of the ternary alloys were calculated. Using the related binary data, the equation derived previously by us represents well the excess molar free energies of the ternary system.View full abstractDownload PDF (875K) -
Morimasa Saito, Emiko Sudo1987 Volume 51 Issue 7 Pages 673-677
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA conventional vacuum fusion method which is used as a standarization method of oxygen contents in metals has a disadvantage in being too time-consuming for degassing the graphite crucibles. The addition of a small amount of Si into the graphite crucible rapidly decreased the oxygen blank, and it was also found that Cr gives the same effect as Si. When the crucible was degassed for 1.8 ks at 2573 K after the addition of Si or Cr, the oxygen blank values were reduced under 5 μg/600 s. This technique was suitable for a rapid and accurate determination of oxygen in metals.
The mechanism of the rapid decrease of the oxygen blank was assumed as follows:
(1) Rapid evaporation of metals on the wall of the graphite crucible in vacuum at 1673-1973 K.
(2) Deep penetration of metals into the graphite crucible.
(3) Reaction of metals and the oxides in the graphite crucible.
(4) Reaction of metal oxides and graphite.
(5) Extraction of carbon monoxide in vacuum.View full abstractDownload PDF (651K) -
Determination of CO2 Contents in Slags and Molten Salts by B2O3 Fusion Method and KBF4 Fusion MethodKoichiro Koyama, Yasuhiko Hashimoto1987 Volume 51 Issue 7 Pages 678-685
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTwo methods have been developed which can be widely used for determining CO2 (carbonate ion) contents in oxide-containing melts, and designated as B2O3 fusion method and KBF4 fusion method respectively. The latter is applicable to chloride melts. The methods consist of two simple procedures: (1) fusion of a sample and B2O3 or KBF4 to evolve CO2 from the sample, and subsequently (2) determination of the amount of CO2 evolved by the weight loss method or the Askarite absorption method, or by a commercially available carbon analyzer. The present methods have been applied to determine the CO2 solubilities of the Na2O-SiO2 system at 1473 K under 101325 Pa of CO2 and the NaCl-Na2O system at 1073 K under 101325 Pa of CO2. The present methods were found to be applicable even to melts to which the thermobalance method is inapplicable because of the low solubilities of CO2 or the evaporation loss of the melts.View full abstractDownload PDF (1208K) -
Shouichi Ochiai, Osamu Noguchi, Manabu Ueno1987 Volume 51 Issue 7 Pages 686-693
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUsing pure nickel and aluminum powders, NiAl alloys (36∼38 at%Al) were manufactured by the vacuum hot pressed powder metallurgy method. Characteristics of martensitic transformation and microstructures in the sintered NiAl alloys were investigated. The results obtained are as follows:
(1) By presintering technique (973 K-7.2 ks) followed by hot pressing (64 MPa, 1523 K-0.3 ks) in a vacuum, NiAl sintered alloys having a relative density higher than 99% of the theoretical values were obtained.
(2) Observation of microstructures in the sintered NiAl specimens which were quenched from 1573 K into ice brine reveals a complete martensitic structure.
(3) The increase in density (about 1%) and the decrease in hardness (about 5%) were observed in the quenched specimens compared with those before quenching. Both can be explained qualitatively in terms of crystal structure change.
(4) All sintered NiAl alloys exhibit a good shape memory effect. Reverse transformation temperature (Af) was estimated from the temperature for shape recovery and it was found that Af reduces intensely with the increase of Al content having a slope, about −160 K/at%Al. The tendency of a remarkable composition dependence of transformation temperatures is discussed in terms of the stability of the NiAl parent phase with respect to the martensite phase.
(5) When the NiAl sintered specimens having martensite structure are bent with large deformation at room temperature, they tend to fail in the manner of cleavage fracture.View full abstractDownload PDF (3003K) -
Naoya Fujita, Y\={u}k\={o} Hanatate, Shinji Tsuji, Masakazu Miyagi1987 Volume 51 Issue 7 Pages 694-699
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn a previous report, the authors showed that shape-changes in the temperature range 700∼1000 K occur during thermal cycles up to about 1000 K in a Cu-27.6 mass%Zn-3.8 mass%Al alloy which was deformed at room temperature after being quenched from the β phase region to 273 K. The amount of shape-change increases with increasing maximum temperature during the thermal cycles.
In the present report, using a Cu-25.3 mass%Zn-3.9 mass%Al alloy, the effect of deformation temperature on the shape-change has been studied. The samples were deformed at temperatures from 77 to 670 K, using a die in a salt bath, an oil bath, etc. The maximum temperature of each thermal cycle is set at 1000 K. The results show that the amount of shape-change by the thermal cycle is constant for the deformation in a temperature range lower than about 300 K, increases for the deformation up to about 400 K and decreases for the deformation in a higher temperature range. No appreciable shape-change, however, can be detected at 670 K. In the case of the deformation at higher temperatures than 420 K, it was observed that the amount of shape-change decreases with increasing heating time before the deformation.View full abstractDownload PDF (787K) -
1987 Volume 51 Issue 7 Pages 700a
Published: 1987
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPlease see pdf. Wrong:αW=(2Q1+Q2) (7) Right:αW=(2Q1+Q2)View full abstractDownload PDF (66K) -
1987 Volume 51 Issue 7 Pages 700b
Published: 1987
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 (66K)
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