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Volume 46, Issue 1
Displaying 1-17 of 17 articles from this issue
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Masami Onishi, Toshitada Shimozaki1982 Volume 46 Issue 1 Pages 1-8
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSWhen molar fluxes (unit: mol/m2·s) are employed for binary interdiffusion, there are supposedly three types of fluxes. The first and second are the fluxes measured relative to the volume and the number of moles fixed frame of reference, respectively. The last are the fluxes which pass through the plane fixed relative to Kirkendall marker.
On the assumption that the total molar volume of alloy is a linear function of mole fraction, reference planes of the first fluxes are fixed relative to x axis. Reference planes of the second fluxes are not fixed relative to the x, but to ξ axis. Although intrinsic fluxes relative to the marker plane are independent of the frame of reference, moving velocity of the marker which is observed from the x differs from that observed from the ξ. Intrinsic diffusivities calculated by use of marker velocity, therefore, depend on the frame of reference.
The intrinsic diffusivities, Di, obtained on the volume fixed frame of reference are represented by the following equation
(This article is not displayable. Please see full text pdf.)
\ oindentwhere \ ildeD is the ordinary interdiffusion coefficient and CiVi (i=1, 2) is volume fraction. When D1 is assumed to be equal to D2, the sum of intrinsic flux of component 1 and that of component 2 is not equal to zero. The intrinsic diffusivities obtained on the number of moles fixed frame of reference have the same characteristics as the diffusivities represented by the well-known Darken’s relation which has been derived on the assumption of constant molar volume.View full abstractDownload PDF (681K) -
Yuichiro Murakami, Sukeji Kachi1982 Volume 46 Issue 1 Pages 8-12
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe relation between the vacancy concentration and the ordering in the Heusler alloy was analyzed by the Bragg-Williams approximation, taking into account the interaction of atoms between the 1st and 2nd near neighbours, where the energy of the free bond extending toward a vacant site was assumed to be zero. By the effect of the CsCl(B2)-type or the Heusler(L21)-type ordering, the disparity of the vacancy concentration on the sublattice sites was found to appear. As an example, the degree of the B2-type order (S1), that of the L21-type order (SH) and the vacancy concentration on the three sublattice sites in the AuAgZn2 Heusler alloy were calculated as a function of temperature.View full abstractDownload PDF (403K) -
Masaaki Fukuchi, Katsuya Watanabe1982 Volume 46 Issue 1 Pages 12-16
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe shear system of Ni3Nb was studied by the measurement of anisotropy in the Knoop hardness on the (100), (010) and (001) surface planes of a single crystal. The hardness varied remarkably with changing crystal plane and indenter direction. From the deformation traces around indentations, several shear systems were assumed. The orientation dependence of the Schmid factor for the shear systems assumed were computed. The hardness anisotropy was explained in terms of four operative shear systems. They were (010)[001], (010)[100], {211}⟨‾10 7 13⟩ and {101}⟨10\bar1⟩, and the resolved shear stress is considered to increase in this order. It was supposed that the shear mode for the two (010) systems was due to slipping and that for the rest systems was due to twinning.View full abstractDownload PDF (478K) -
Masayuki Hasaka, Hiromichi Nakashima, Kensuke Oki1982 Volume 46 Issue 1 Pages 16-21
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPolystyrene latexes with particles of diameters 250 and 500 nm are observed under a metallurgical microscope.
The crystal structures of the RCo5 and R2Co17 types appear stably through thermal motion of particles, where R means rare earth atoms. A variety of defects such as diffuse interfaces, dislocations, point defects, amorphous structures, or segregations of large and small particles are distinctly observed in these structures. Polystyrene latexes are found to be useful to study on a atomic scale the crystal structures and their kinetic behaviors of intermetallic compounds of the R-Co system.View full abstractDownload PDF (1242K) -
Koji Tanoue, Hidehiko Matsuda1982 Volume 46 Issue 1 Pages 22-27
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAny stress relaxation curve for polycrystalline molybdenum, obtained from stress relaxation tests by a monotonic loading mode and plotted as logσ vs log\dotε, can be superposed each other by scaling and forms a unique master curve. The effects of such various factors as grain size, imposed strain rate, impurities and temperature on the shape of the master curve are investigated. A deeper understanding of the characteristics and the physical meaning of the master curve has been acquired by investigating the experimental results.
The primary shapes of master curves are not affected by the factors of grain size and imposed strain rate, and the master curves can also be superposed each other by scaling. Subsequently, the stress-strain rate scaling parameter \barm{=(δln\dotε⁄δlnσ)ν} obtained as a reciprocal of the slope \barμ on scaling of master curves coincides with m on forming each master curve. On the other hand, the master curves obtained by changing the amount of impurities and temperature cannot be superposed each other because of the different shapes of the master curves. It is concluded from the results that the different shapes of the master curves may be attributed to the change in shortrange profiles for dislocation movement due to impurities and to the change in the effective stress due to temperature.View full abstractDownload PDF (478K) -
Tetsuro Ishizaki, Takao Takeda, K\={o}ichiro Higashi1982 Volume 46 Issue 1 Pages 28-37
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHydrogen evolution from steels containing ε-Cu precipitates has been examined by a method of continuous heating up to 1273 K in a vacuum quartz tube attached to a quadrupole mass spectrometer system.
Hydrogen in steels becomes undiffusible mainly because of the interaction force between carbon or nitrogen and hydrogen, and it evolves due to decrease in the interaction force with an increase in temperature. Hydrogen in the dislocation area becomes undiffusible because of the interaction force among vacancy, dislocation, carbon or nitrogen and hydrogen. As the amount of solutes (C+N) decreases with increasing Cu clusters, the amount of undiffusible hydrogen decreases.View full abstractDownload PDF (834K) -
Teruo Kiyosawa, Katashi Masumoto1982 Volume 46 Issue 1 Pages 38-42
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe activity of the CdSe phase in the CdCr2Se4 phase was measured as a function of the Se vapor pressure and temperature by observing the condensation of CdSe(s) from the vapor phase in equilibrium with CdCr2Se4 which coexisted with CdSe or Cr2Se3 (or Cr3Se4). Also the PSe2−aCdSe (Se2 vapor pressure-activity of CdSe) phase diagrams at 982, 1084 and 1138 K were determined.
Data obtained allowed to estimate the free energy of formation of CdCr2Se4 from CdSe(s) and Cr2Se3(s); ΔGT=−19700+17T (J/mol), and to disclose the change in activities of Cd and Cr in the CdCr2Se4 phase with Se vapor pressure.View full abstractDownload PDF (383K) -
Tatsuhiko Ejima, Kazuyoshi Shimakage, Tsutomu Yamamura, Yuzuru Sato, T ...1982 Volume 46 Issue 1 Pages 43-52
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMeasurements of Brillouin scattering have been carried out on the NaNO3-KNO3 binary melts at the temperatures ranging from the liquidus temperatures of the melts to 810 K over the entire range of composition. A He-Ne gas laser with the wave length of 386.2 nm was used as a light source. The scattered light was analyzed with a pressure-scanned Fabry-Perot spectrometer. The hypersonic velocity and some thermodynamic properties were determined. Results obtained are summarized as follows:
(1) The hypersonic velocity decreased almost linearly with increasing temperature over the entire range of composition.
(2) The isothermal hypersonic velocity was additively dependent upon the composition of the melt.
(3) The hypersonic velocities obtained were about the same as the reported ultrasonic velocity at the composition rich in NaNO3, and significantly greater than the ultrasonic velocity at the composition rich in KNO3 considering the experimental errors of the present study and the measurement of ultrasonic velocity. This dispersion of sound propagation indicates that the relaxation frequencies for the melts rich in KNO3 and for those rich in NaNO3 are less than 3 GHz, the lowest in the experiments and more than 7 GHz, the highest, respectively. The structural relaxation of associated species of anions and cations may cause the dispersion observed.
(4) The compressibility, the heat capacity and the internal pressure were calculated from the hypersonic velocities determined. The values of internal pressure were nearly the same as those of typical ionic melts, such as alkali-metal chlorides. The NaNO3-KNO3 binary melt can be regarded as an ionic melt though it contains associated ionic species.View full abstractDownload PDF (763K) -
Tatsuhiko Ejima, Kazuyoshi Shimakage, Toshinobu Yoko, Tatsuo Kato, Shu ...1982 Volume 46 Issue 1 Pages 53-59
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSVelocities of ultrasonic waves in molten NaCl-CaCl2 and NaCl-MgCl2 binary systems have been measured with a U.S. spectrometer by the double-transducer method over the frequency range from 5 to 55 MHz. Experimental results obtained are summarized as follows:
(1) Velocities of ultrasonic waves for these systems increased in the order of pure MgCl2<pure NaCl<pure CaCl2. The relation between the ultrasonic velocity and the experimental temperature was represented by a stright line having a negative temperature gradient over the entire range of composition.
(2) Thermodynamic quantities such as the adiabatic and isothermal compressibilities, the heat capacity at constant volume and the internal pressure were calculated from the measured velocity data, and their composition dependences were obtained. The adiabatic compressibilities and the internal pressure calculated from the measured ultrasonic velocity changing with composition were explained by considering the change in the consitituents existing in the melt.
(3) On the basis of the present results, the liquid structures of these binary systems were discussed. The present results were well supported by a presumption derived from the results of density, viscosity coefficient and surface tension measurements which were reported in previous investigations.View full abstractDownload PDF (553K) -
Nobuya Shinozaki, Tetsunari Kurashige, Katsumi Mori, Yasuji Kawai1982 Volume 46 Issue 1 Pages 60-66
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe interfacial tension between liquid iron and slag containing iron oxide and manganese oxide was measured at 1873 K by the sessile drop method with X-ray technique for non-equilibrium and equilibrium conditions.
Results obtained are as follows:
(1) When change in the oxygen contet of liquid iron during a run was less than 0.05 mass%, change in the interfacial tension followed the change in the oxygen content of liquid iron. However, when the iron oxide content of slag was high and the change in the oxygen content of liquid iron was more than 0.09 mass%, the interfacial tension was kept at nealy constant low values, that is, the interfacial tension was determined by the iron oxide content of slag.
(2) In the case of transferring of oxygen of about 2×10−2 mol/m2s, the contour of an iron drop on an X-ray film was dim, indicating the occurrence of weak interfacial turbulence.
(3) The interfacial tension was determined primarily by the oxygen content of liquid iron or the iron oxide content of slag. The influence of manganese on the interfacial tension was little.
(4) From the Gibbs adsorption isotherm, excess quantities at the interface for oxygen and manganese were calculated to be 2.0×10−5, 0.4∼1.5×10−5 mol/m2, respectively.
(5) The relation between the interfacial tension and the oxygen activity of liquid iron was given by the following equation:
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Takeo Oki, Hiromitu Kondou, Saburou Kuwano1982 Volume 46 Issue 1 Pages 67-72
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe SCC of the Type 304 austenitic stainless steel in 3%NaCl solution (293 K) was studied by the potentiostatic CERT method in conjunction with its polarization behavior. The mechanical properties and the current flowing through the specimen were measured by the potentiostatic CERT method in the range of crosshead sbeed from 1.67×10−7 m/s to 1.67×10−5 m/s, and the fracture surface was examined by a scanning electron microscope. From the polarization behavior of the Type 304 stainless steel in 3%NaCl solution at 293 K, it was found that the specimen was very susceptible to the SCC in the pitting potential (0.34 V vs NHE), and was immune to the SCC both in the steady passive potential (−0.06 V vs NHE) and the unsteady one (1.14 V vs NHE).
The tensile strength and the reduction of sectional area in the pitting potential decreased remarkably at the low crosshead speeds below 1.67×10−6 m/s, and this was most likely due to the SCC caused from the pitting corrosion.View full abstractDownload PDF (695K) -
Takeo Oki, Hiromitu Kondow, Saburou Kuwano1982 Volume 46 Issue 1 Pages 73-77
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe susceptibility to the SCC of Type 430 ferritic stainless steel in 3%NaCl solution at 293 K has been studied by the potentiostatic CERT method in relation to the polarization behavior of the steel in the solution. Effects of the crosshead speed on the tensile strength, the reduction of sectional area and the current of the specimens have been examined at potentials in the pitting region (0.29 vs NHE) and the unsteady passive region (−0.06 vs NHE) with crosshead speeds in the range from 1.67×10−5 to 1.67×10−7 m/s. It was found that Type 430 stainless steel was susceptible to SCC in the potential region above the pitting potential but immune in the region of the unsteady passivity in a 3%NaCl solution: Remarkable decreases in the tensile strength and the reduction of sectional area occurred when the specimen was strained with crosshead speeds below 1.67×10−6 m/s at potentials above the pitting potential in the solution. The SEM observation on the fractured surfaces of the specimens after CERT showed SCC started from the bottom of the pits. These facts emphasize the importance of pitting in the initiation of the SCC of the steel.View full abstractDownload PDF (704K) -
Hisashi Suzuki, Motohiro Kanno, Goroh Itoh, Kazuhiro Itoi1982 Volume 46 Issue 1 Pages 78-84
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe precipitate structures in Al-0.6 and 1.1 mass%Si alloys subjected to several sorts of heat-treatments including the normal aging, the two-step aging, the aging after quench-interruption, etc. were studied mainly by means of transmission electron microscopy. The number density of silicon precipitates was increased with elevation of the solution temperature, and with lowering of the aging temperature and the quenching bath temperature. The density was also increased by the two-step aging. However, in the case of the aging after quench-interruption, coarse precipitates with no uniformity in the distribution were always observed even after the two-step aging. These results seemed not to be well explained in terms of previous theories. An alternative theory is introduced assuming that solute-vacancy clusters are formed and grow at low temperatures more easily as the excess vacancy concentration is increased, to act as nuclei of silicon precipitates.View full abstractDownload PDF (1943K) -
Shigenori Yuyama, Yoshihiro Hisamatsu, Teruo Kishi1982 Volume 46 Issue 1 Pages 85-93
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCorrosion fatigue (CF) characteristics and Acoustic Emission (AE) produced during the CF processes have been studied for a solution treated 304 austenitic stainless steel. The CT specimens (W=50.8 mm, B=25.4 mm) precracked were tested under cyclic tension-tension load (R=0.1, 1 Hz, sine wave), polarized potentiostatically in 0.5 kmol/m3 H2SO4+0.5 kmol/m3 NaCl at room temperature. Valuable AE signals discriminated from environmental noises by the source location using two corrosion resistant AE sensors were measured only at the load phase near the maximum load. The experimental results showed that the crack growth rates at −0.8 V (cathodic region), Ecorr (corrosion potential), and −0.28 V (active region) were accelerated significantly, compared with that in air or at +0.1 V (passive region), at lower ΔK level than 37 MPa·m1⁄2 where the plastic zone at the crack tip changed from hinge-type to shear-type. Both AE cumulative event counts and energy (square of peak amplitude) represened steplike curves and their increasing rates were found to become greater with the acceleration of crack growth rates. Cleavage-like cracking, whose plane was (111), was concluded to be the main AE source during the crack growth process under high stress triaxiality, since the number of the (111) planes was proportional to the AE events detected in Air or passive region when the plastic zone was hinge-type (ΔK<∼37 MPa·m1⁄2). The AE energy rate per cycle at −0.8 V, Ecorr, and −0.28 V, under which environmental conditions hydrogen evolves, was about one order higher than that of +0.1 V or in air, even if the macroscopic crack growth rate was equal. SEM observations of the crack surfaces obtained in these environments found many microcracks nucleated perpendicularly to the main crack surface at chain-like non-metallic inclusions precipitated continuously in the direction of hot rolling. The higher AE energy rate was ascribed to the nucleation of these microcracks due to hydrogen and the triaxial stress field. AE technique was shown to be quite effective to study such processes as cleavage-like cracking, nucleation of microcarcks, transition of mechanical condition in the crack tip plastic zone etc., which take place microscopically in the material.View full abstractDownload PDF (909K) -
Joo Ishihara, Isao Ikuta1982 Volume 46 Issue 1 Pages 94-99
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMany cavities originating from air bubbles exist on the bottom surfaces of amorphous ribbons made by the single roller method. These cavities have an injurious effect on the degree of surface fineness of the ribbons.
Amorphous ribbons with uniform surface are required for the purpose of application. Therefore, the double roller quenching method was investigated to make uniform amorphous ribbons.
A house-made double roller apparatus with rolls 100 mm and 120 mm in diameter was used. Roll pressure was controlled by oil-pressure. Nozzles are made of quarts with single hole or multiple holes. The surface temperature of the roll was measured during the melt-ejection. Puddle formation by the melt jet on the roll surface was observed by a high-speed movie print. The relation between manufacturing variables and the non-uniformity of thickness was examined. Any cavities do not occur with the double roller method because of the roll pressure. Thus it is expected that if the roll surface is fine, ribbons with uniformity may be obtained with the double roller method.
It has been found that the thermal expansion of the rolls is not a main cause of the non-uniformity of thickness. It is considered that the non-uniformity of thickness is caused by the difference in the reduction rate along the width of the roll resulting from the temperature distribution in the melt puddle.View full abstractDownload PDF (522K) -
Kazuyoshi Sekine, Osamu Yoshimura1982 Volume 46 Issue 1 Pages 100-107
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt is well known that under conditions of high friction between rolls and material a unique texture called the surface texture, which is distinctly different from the center texture, appears in the surface layer of a rolled sheet.
In this paper, the rolling process under conditions of high friction is regarded as the sheet compression between two parallel rough plates. Therefore, two types of shear mode of deformation having opposite shear-directions arise in the surface layer of sheet in addition to the ideal plane strain compression. From such a model, the development of the surface texture in rolled bcc polycrystalline metals is simulated as a function of rolling reduction on the basis of the theory already proposed by the authors, in which the final orientations of deformation textures in polycrystalline metals can be uniquely predicted. Also the variation of texture through the thickness of the sheet rolled under conditions of high friction between rolls and material is predicted by computer simulation. The simulated textures at various layers throughout the sheet thickness are in agreement with the experimental ones of cold-rolled niobium reported by Vandermeer and Ogle.View full abstractDownload PDF (588K) -
Shigeo Zaima, Yuzo Takatsuji, Shigeru Yamada, Hiroki Okushima1982 Volume 46 Issue 1 Pages 108-116
Published: 1982
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTool wears were discussed from the viewpoint of crater by means of EPMA in dry cutting extra super duralumin (7075-T6) using carbide tools P10 and K10. Results obtained are as follows: When hard particles expected to exist in the 7075 structure, for example, FeAl3 etc., flow out in the chip, the scratching wear on the surface grew, and iron oxide adhered to the terminal wear parts as a black adhesion. Many particles composed of (WC+TiC) in the tool structure were cracked during the cutting, while particles composed of WC only survived longer. Consequently, the progression of tool wear of K10 tool is slower in general than that of P10 tool.View full abstractDownload PDF (1339K)
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