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Volume 55, Issue 6
Displaying 1-17 of 17 articles from this issue
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Keiichi Edagawa, Tatsuo Sugawara, Shinpei Tokoh, Fumie Seki, Katsuro O ...1991 Volume 55 Issue 6 Pages 607-614
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSX-ray pole figures have been measured for icosahedral Al68Si4Ru8Mn20, Al100−xMnx x=21, 17, 14, Al60Li30Cu10 and Al65Cu20Fe15 quasicrystals produced by melt-spinning. Single icosahedral phase was obtained for the samples except for Al100−xMnx x=17 and 14. In the two samples, fcc-Al phase coexists.
In the samples consisting of single icosahedral phase, the 5-fold axis is preferentially alligned in the direction normal to the ribbon surface. The observation of the cross section of the ribbon by SEM has shown that grains of this phase grow columnarly from a roll side surface to a free side surface. These results lead to the conclusion that the direction of the columnar growth is parallel to the 5-fold axis.
In the samples which contain the fcc-Al phase, no texture is observed for the icosahedral phase. Instead, a (111) texture is found for the fcc-Al phase. The absence of texture for the Al-Mn, icosahedral phase is consistent with the observation that most of the grains in the icosahedral phase are spherical.View full abstractDownload PDF (2112K) -
Jirou Harase, Ryo Shimizu, Yakitirou Kawamo, Yoshiyuki Ushigami1991 Volume 55 Issue 6 Pages 615-621
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTexture evolution by grain growth in cold-rolled and annealed {110}⟨001⟩ Fe-3%Si single crystal containing no precipitates was investigated by SEM-ECP.
Main findings were as follows.
(1) Primary recrystallization texture after 60% cold reduction (108 μm) was {110}⟨001⟩ and the texture evolved by grain growth was {120}⟨001⟩.
(2) Primary recrystallization texture after 82.6% cold reduction (47 μm) consists of {441}⟨6 7 52⟩ and {661}⟨2 5 42⟩ and no substantial texture change occurred by grain growth.
(3) The mechanism of the {120}⟨001⟩ orientation evolution by grain growth is considered to be due to the inhibition effect of higher frequency of Σ1 boundaries present in the primary matrix and the higher frequency of Σ19a coincidence orientation relationship between the grains evolved by grain growth and the primary matrix grains. This mechanism can be considered to be the same as that of the secondary recrystallization in FCC alloys containing no precipitates.View full abstractDownload PDF (845K) -
Jirou Harase, Sh\=ozaburou Nakajima, Yakitirou Kawamo, Yasunari Yoshit ...1991 Volume 55 Issue 6 Pages 622-629
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA primary recrystallized specimen having few grains with Goss orientation was made by Taguti’s method through increasing cold rolling reduction and it was then annealed in a 100%N2 or 100%H2 atmosphere.
The {110}⟨111⟩ secondary recrystallization was evolved and no {110}⟨001⟩ secondary grains were made when annealed in a 100%N2 atmosphere. Normal grain growth with a major orientation of {113}⟨14 23 3⟩ occurred when annealed in a 100%H2 atmosphere.
The mechanism of the evolution of {110}⟨111⟩ secondary recrystallization can be considered to be due to the relatively higher intensity of the nucleus compared with that of {110}⟨001⟩ and the second highest frequency of gains in Σ9 orientation relationship compared with that of a Goss grain in the primary matrix. The mechanism of the evolution of normal grain growth with a {113}⟨14 23 3⟩ major orientation may be due to the selective grain growth of the surface layer of the primary recrystallized specimen caused by a decrease in the inhibition effect of AlN precipitates in the surface layer, which has {113}⟨14 23 3⟩ as the major orientation.View full abstractDownload PDF (1070K) -
Yasunari Yoshitomi, Kenzou Iwayama, Takeo Nagashima, Jirou Harase, Nob ...1991 Volume 55 Issue 6 Pages 630-638
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSecondary recrystallization behavior in the presence of AlN and MnS precipitates in Fe-3%Si alloy, processed by Taguchi’s method, was investigated with special reference to a role of inhibitor for secondary recrystallization. Primary recrystallized sheets were heated up at a constant rate for the evolution of secondary recrystallization under the two different conditions changed by control of annealing atmospheres, i. e. under stronger grain growth inhibition by precipitates and weaker one, just after the beginning of secondary recrystallization. Main findings obtained are as follows:
(1) With stronger grain growth inhibition by precipitates during secondary recrystallization, the number of secondary recrystallized grains decreases and the finishing temperature of secondary recrystallization increases.
(2) The sharpness of Goss secondary texture is higher in the early stage of secondary recrystallization. In the case of weaker grain growth inhibition by precipitates during secondary recrystallization, the secondary recrystallized grains in orientaions apart from Goss orientaion are evolved during the later heating stage. On the other hand, in the case of stronger grain growth inhibition, the evolution of the secondary recrystallized grains in orientaions dispersed from the Goss orientaion during the later heating stage is smaller.
(3) The mechanism of these experimental results is explained by the specific grain boundary migration characteristics in the presence of inhibitor, namely, the critical frequency of Σ9 coincidence oriented grains in relation to nucleus for the evolution of secondary recrystallization is considered to be higher in the case of stronger grain growth inhibition during secondary recrystallization.View full abstractDownload PDF (1989K) -
Hajime Saitoh, Kohsaku Ushioda1991 Volume 55 Issue 6 Pages 639-645
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe influence of P on the solubility of C in ferrite equilibrium with cementite was investigated in low carbon steels containing P ranging from 0 to 0.21 mass% over a temperature from 573 to 973 K. Internal friction method was employed together with chemical analysis of C by means of the infrared absorption method after combustion.
It has been clarified that P increases the solubility of C in ferrite in equilibrium with cementite, whereas P reduces the Snoek peak height despite the fact that the amount of C in solid solution is constant. The proportionality constant K in the equation, Sol. C (mass ppm)=K×Qmax−1(10−4), was experimentally determined as a function of P content and it was clarified that K increases with increasing P content.
Taking into account the fact that the reduction of Sneok peak height increases with Co, Mn, and P addition in this order, the elastic strain around the substitutional atom due to the diffrence in atomic radius is postulated to be the main reason why Snoek peak height decreases with the addition of alloying elements. Here, the solute C in the lattice-strained region is supposed to be unable to contribute to the Snoek peak.View full abstractDownload PDF (1035K) -
Tohru Yamasaki, Katsuji Nagasawa, Yoshikiyo Ogino, Asahi Kawashima, Ko ...1991 Volume 55 Issue 6 Pages 646-653
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of hydrogen on the ductility and structure of Fe78(B1−xPx)15Si7 amorphous alloys (x=0∼1.0) has been examined by measuring the ductile-brittle transition temperatures (DBTT), the electrical resistivities and Mössbauer effects. By cathodically charging the specimens with hydrogen, the DBTT rises with an increase in absorbed hydrogen contents. The electrical resistivity and the isomer shift of hydrogen charged specimen have indicated that the hydrogen embrittlement at temperatures below the DBTT is caused by the formation of hydride-like bonding between B, P and H. The increase in DBTT by hydrogenation is decreased by increasing P contents. This may be due to the lower dissolution temperature of P-H bonding than B-H bonding in the alloy.View full abstractDownload PDF (1330K) -
Kuniomi Wase, Yoichi Maru, Sanji Nishimura1991 Volume 55 Issue 6 Pages 654-659
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to study the phase equilibrium and the behavior of sodium between aqueous solution containing sodium and versatic acid 10 without diluent, the equilibrium of the H2O-NaNO3-VA10 system, the H2O-NaOH-NaNO3-VA10 system and the H2O-NaOH-VA10 system were investigated at 298 K.
In the case of aqueous solution containing NaOH, the logarithmic distribution ratio, logDNa, increases approximately linearly with pH in the range of 5.5 to 6.8, then decreases through a maximum value and finally approaches DNa=1 at a pH value of nearly 8. On the other hand, sodium is hardly extracted by versatic acid 10 from aqueous solution without NaOH in the region of pH values below 4.
The liquidus surface and tie lines between organic and aqueous phases were constructed on a composition tetrahedron of the H2O-NaOH-NaNO3-VA10 system. It is found that sodium is concentrated in the organic phase more than in the aqueous phase. It seems that the organic phase is equilibrated with the aqueous phase which liquidus surface extends towards the direction of two components of NaOH and NaNO3.View full abstractDownload PDF (928K) -
Satoshi Sunada, Nobuyuki Nakamura, Hirotugu Kawase, Hisakimi Notoya, S ...1991 Volume 55 Issue 6 Pages 660-666
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of the deformation-induce martensite (α′) on the general corrosion of SUS304 austenite stainless steel in dilute H2SO4-NaCl solution was investigated by means of an electrochemical measurements and optical microscopic observation.
The main results obtained are summarized as follows:
(1) The corrosion resistance of SUS304 stainless steel in the active state region decreases with increasing volume fraction of martensite, decreasing of the solution and increasing solution temperature.
(2) The corrosion of SUS304 steel containing martensite in the active state region is almost uniform. However, the selective dissolution of the martensitic phase in the specimens occurs.
(3) The corrosion rate of the martensitic phase is about 1.65 times as large as that of the austenitic phase at the volume fractions of martensite below 50%. And at the volume fraction more than 50%, the rate is more enhanced with increasing volume fraction of martensite. However, no change in corrosion mechanism of SUS304 steel is observed regardless of whether martensitic phase is presented or not.View full abstractDownload PDF (1236K) -
Toshio Shimoo, Yoshihiro Konishi1991 Volume 55 Issue 6 Pages 667-674
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn relation to the smelting reduction of chromite ore, the mechanism of reduction of synthetic chromites (Fe0.5Mg0.5) (Cr0.8Al0.2)2O4 and Mg(Cr0.6Al0.4)2O4 with solid carbon has been studied by means of thermogravimetry, metallography and chemical analysis. The reduction rate of powdered chromite-graphite mixture has been measured under an argon atmosphere at high temperatures from 1773 to 1973 K.
(1) With small particles of (Fe0.5Mg0.5) (Cr0.8Al0.2)2O4, the FeCr2O4 component was reduced preferentially and the molten Fe-Cr-C alloy was finely dispersed. In the stage of reduction of the Mg(Cr0.6Al0.4)2O4 component, chromium carbide was formed around the graphite particles. The reduction rate was mixed-controlled by the gaseous diffusion through the interparticle pores and the Boudouard reaction. With large chromite particles, there was uniform internal reduction, such that the rate was represented by a first-order-type equation. The rate was mixed-controlled by the gaseous diffusion through the porous chromite particles and the subsequent gaseous reduction.
(2) In the case of the reduction of powdered Mg(Cr0.6Al0.4)2O4, the graphite particles were coated with carbide. The rate-determining step was the solid state diffusion through the carbide. The reduction mechanism of the coarse particle was similar to that in (Fe0.5Mg0.5) (Cr0.8Al0.2)2O4.View full abstractDownload PDF (1842K) -
Atsumi Ohno, Genjiro Motoyasu, Masaru Takahashi1991 Volume 55 Issue 6 Pages 675-680
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt has been demonstrated that strips with unidirectionally solidified structures can be produced by a new heated rotary mold continuous casting process (the mold is also heated above the solidification temperature of the molten metal). An apparatus for this process was constructed and trial experiments with zinc were performed, and then the strips of zinc were produced under several manufacturing conditions. The relationships between the solidification structures of the strips and casting conditions were investigated. This apparatus can produce zinc strips, 100 mm wide, 3 mm thick and 3 m long at 2.5∼25 mm·s−1 casting speed. All the strips had single crystal structure or unidirectionally solidified structure without equiaxed crystals. The structures were affected by cooling conditions and casting speeds.View full abstractDownload PDF (1750K) -
Shigeru Yonetani, Katsuya Imai1991 Volume 55 Issue 6 Pages 681-689
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSResidual stresses in brass bar which were heavily cold drawn to cross-sectional reductions from 25 to 78% were measured. Specimens used were as extruded and annealed after extruding. These were cold drawn stepwise by the two kinds of cross-sectional reduction rate of about 20% per pass and heavier percentage per pass. The residual stresses of the specimens after drawing were almost tensile at the outer part and compressive at the inner part in the section, the distribution of which changes considerably with the increase of reduction under 60% total reduction but hardly over 60% total reduction. At the same time, residual shearing stresses in the section of each specimens were measured. It was shown that these correlate with residual microstrains in the deformed structures. Textures at the outer and inner parts in the section were measured, which changed with the increase of reduction respectively. The influence of the formation of texture on the generation of residual stress was discussed.View full abstractDownload PDF (1318K) -
Yoshiaki Shida, Hiroyuki Anada1991 Volume 55 Issue 6 Pages 690-695
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSOxide scale structure of binary Ti-Al alloys containing 20 to 63 mass%Al oxidized in air was studied at 1073 K, 1123 K and 1173 K. As a result, it was observed that for alloys containing less than 51%Al multilayered scale was formed accompanying internal oxidation zone at the base giving smaller oxidation resistance, while for 63%Al alloy oxidation resistant external scale was formed. It was discussed that for the transition from internal to external oxidation in the Ti-Al alloys very high value of critical internal oxide volume fraction was necessary. Also, the internal oxide morphology appeared to influence the structure of the inner scale layer and then the oxidation rate.View full abstractDownload PDF (1206K) -
Fumiyoshi Kirino, Noriyuki Ogihara, Norio Ohta1991 Volume 55 Issue 6 Pages 696-705
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe TbFeCoNbN film was studied, which was formed by sputtering in a nitrogen atomsphere. This film was not perpendicular anisotropy, but has high corrosion resistance such as wet corrosion and pitting corrosion. So, a nitride film were formed on the TbFeCoNb magneto-optical recording film. When the nitride film was formed on the TbFeCoNb film, the magneto-optical characteristic such as the Kerr rotation angle became smaller with increasing thickness of the nitride layer. The magneto-optical disk was produced, and its disk characteristics was measured. C/N of 45 dB which was capable of recording the code data, was obtained for the disk, being formed on the nitride layer of 5 nm thickness on the surface of the TbFeCoNb film. The reliability of the disk was estimated with the change of C/N and the jitter width on the disk, using the TbFeCoNbN/TbFeCoNb recording film. When this disk was exposed to 60°C-95%RH for 1000 h, C/N and the jitter width were not changed. The results show that this disk has high reliability.View full abstractDownload PDF (1394K) -
Fumiyoshi Kirino, Akiko Mutou, Norio Ohta1991 Volume 55 Issue 6 Pages 706-714
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSiNx films are widely used as protection and Kerr enhancement films for magneto-optical disks. The characteristics of the SiNx films, produced by reaction sputtering using the silicon target, are studied by FT-IR, Auger electron spectroscopy, a microscope, an X-ray diffraction meter, and the ESCA method. The film, produced by a pass-by type sputtering apparatus, a low sputtering gas pressure, and a short length between target and substrate, does not contain oxygen. The reaction sputtering method gives little influence on the sputtering condition. Oxygen is not contained in the film using this production condition. The magneto-optical recording film is corroded, if the SiNx film containing oxygen is used as a Kerr enhancement and protection film. Nitrogen possesses one bonding order, as a independent of production process, and silicon, depended on the process, possesses some state. The surface of this films is flat and amorphous. The magneto-optical disk using this SiNx films has no problems such as the increase δ the noise level.View full abstractDownload PDF (1026K) -
Masakatsu Hinai, Showhachi Sawaya, Hakaru Masumoto1991 Volume 55 Issue 6 Pages 715-719
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAgeing at room temperature in the logarithmic decrement δ and crystal structure were investigated for heat-treated and cold-worked Al-Zn alloys. The volue of δ was measured by an inverted pendulum method and the crystal structure was confirmed by using an X-ray diffractometer method.
The value δ of the Al-Zn alloys containing Zn less than 70% by mass is very low just after water quenching from a temperature of 673 K in the region of the α phase, but becomes higher with time, decreasing gradually after reaching a maximum. The nearer the eutectoid composition, the shorter the decomposition time at which the maximum of δ appears. On the other hand, in the alloys which were water-quenched from 573 K in the region of the (α+β ) phase, δ shows a maximum in a short time than that from the α phase. Which the alloys contained 80 and 90%Zn by mass and were water-quenched from the region of the (γ+β) phase, δ from 623 K is higher than that from 573 K, and both values reach maxima just after quenching and then decrease gradually. The variation in δ may be explained as follows. In the alloys with the α phase, δ is very low but becomes gradually higher with the increase in precipitation of the β phase due to the eutectoid decomposition reaction, it then decreases gradually with the slow growth of the grains after reaching a maximum.
The value δ upon furnace cooling is very low, whereas upon cold working it becomes higher because of the refinement of grains and the increasing dislocations caused by working. Further, by cold working after water quenching, δ is increased considerably. However, in the cold-worked states, δ becomes lower gradually with time.View full abstractDownload PDF (657K) -
Masao Morishita, Masahiro Chikuda, Yoshio Ashida, Masahiko Morinaga, N ...1991 Volume 55 Issue 6 Pages 720-726
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to understand cathodic reactions of Ti-based alloys, local electronic states of the cathode were simulated by a DV-Xα cluster method. The basis of the assumption of a local electronic cell model in which the anode was the titanium-matrix region and the cathode was the alloying-element containing region. The molecular orbital calculation shows that two conditions are required for the enhancement of the cathodic reaction in aqueous solutions: (1) the density of states near the Fermi level should be large enough to localize conduction electrons in the cathode region, and (2) the energy of the Fermi level should be high enough to discharge localized electrons so that the hydrogen evolution on the cathode surface proceeds smoothly. This conclusions were supported experimentally by a series of the measurements of polarization curves with Ti-0.1% (mole fraction) M alloys (M = W, Re, Ir, Pt, Au, Mo, Ru, Rh, Pd, Ag, Fe, Co, Ni and Cu) in 10% (mass fraction) H2SO4 solutions. An active cathodic reaction was observed when the alloy contained one of the elements that satisfied the above conditions: Ir, Pt, Ru, Rh and Pd. The present results indicate that the simulation based on the molecular orbital theory is useful for describing the local electronic states of cathode in aqueous corrosion.View full abstractDownload PDF (749K) -
Michiko Yoshitake, Kazuhiro Yoshihara1991 Volume 55 Issue 6 Pages 727-728
Published: 1991
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (286K)
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