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Volume 54, Issue 4
Displaying 1-19 of 19 articles from this issue
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Kimiko Sakata, Kazuyuki Ogawa1990 Volume 54 Issue 4 Pages 357-361
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA structure of Fe/FeO interface in a sintered iron and wüstite powder mixture with the composition of Fe-30 mol%FeO was investigated by high resolution electron microscope. The present results were discussed in relation to these of composition analysis already obtained by Auger electron spectroscopy and X-ray photoelectron spectroscopy for the oxidized iron crystal. At the interface (111)Fe/(110)FeO a transition region with oxygen deficiency is formed, which has a distorted cubic structure of Fed. The structure with oxygen deficiency is formed by the diffusion of excess oxygen from wüstite into the Fe-phase and plays an essential role in joining both phases.View full abstractDownload PDF (1555K) -
Tohru Yamasaki, Yoshikiyo Ogino, Terukazu Honda, Yoshiyuki Amemiya1990 Volume 54 Issue 4 Pages 362-371
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to obtain information about the annealing treatment dependence of the ductile-brittle transition temperature (DBTT) of Fe-B-Si amorphous alloys, single bend properties at various temperatures, Mössbauer effects and small angle X-ray scattering (SAXS) using synchrotron radiation were examined. The rising behavior of DBTT depends on the annealing temperature. In the case of Fe77B13Si10 alloy, DBTT saturates to about 290 K when annealed below 623 K. On the other hand, when annealed above 633 K, DBTT rises up to about 290 K at the initial periods of annealing and then steadily rises with increasing annealing times. These results indicate that the embrittling reaction proceeds in two stages: below about 623 K, only the first-stage embrittlement occurs and at higher temperatures the second-stage occurs following the first-stage reaction. The Curie temperature measured by DSC and the SAXS intensity begins to increase from 620 K which well coincides with the starting temperature of the second-stage embrittlement. Mössbauer effect measurement suggests that the first-stage embrittlement is caused by the redistribution of the structural defects which has weak temperature dependence, and the second-stage is caused by the developement of Fe3(B, Si) type and Fe-rich type compositional short-range orders.View full abstractDownload PDF (1370K) -
Jirou Harase, Ryo Shimizu, Nobuyuki Takahashi1990 Volume 54 Issue 4 Pages 372-380
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSecondary recrystallization textures composed of (100)[001] and (100)[011] orientations are evolved from a cross-rolled (60% reduction) and annealed 3%Si-Fe. The (100)[011] secondary recrystallization texture is mainly evolved when cross rolled with 70% reduction.
(1) In the case of 60% reduction, (100)[001] grains are evolved as this orientation has the highest value of ICΣ7 in a matrix texture before grain growth and the intensity of the (100)[001] nucleus (IN) is higher than a critical value. Here ICΣ7 is a intensity of Σ7 oriented grains in relation to the (100)[001] orientation in a matrix texture before grain growth.
(100)[011] grains are evolved as this orientation has the highest PCNΣ7 value in a matrix texture before grain growth. Here the PCNΣ7 value is a product of a intensity of a nucleus orientation (IN), namely, (100)[011], and ICΣ7 in relation to the (100)[011] orientation in a matrix texture before grain growth.
(2) In the case of 70% reduction, (100)[011] grains are evolved by the same mechanism mentioned above. The (100)[001] secondary texture is scarcely evolved in spite of the highest ICΣ7 value in relation to the (100)[001] orientation. This is due to the low IN value of the (100)[001] orientation in a matrix texture before grain growth.
(3) The present results support a grain growth theory proposed by the present authors that the texture evolution by grain growth are closely associated with the intensity of the grains in coincidence lattice relationships and the intensity of the inhibitor.View full abstractDownload PDF (2102K) -
Jirou Harase, Ryo Shimizu, Nobuyuki Takahashi1990 Volume 54 Issue 4 Pages 381-387
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTexture evolution by grain growth in the presence of MnS and AlN precipitates in 3%Si-Fe alloy processed by Taguchi’s method, was investigated by X-ray diffraction and back Laue diffraction. Main findings obtained are as follows:
(1) With higher cold reduction, sharpness of Goss secondary texture increases, however, fine grain areas with no Goss orientation are also evolved. The evolution of the sharper Goss texture is considered to be due to an increase in frequency of Σ9 type grain boundaries in relation to an ideal Goss orientation in the primary matrix by higher cold reduction, and the occurrence of the fine grain area is due to the decrease in the Goss nucleus grains in the primary matrix.
(2) The texture of the above mentioned fine grain area is mainly {334}, while the major texture before grain growth is {113}.
The mechanism of the texture evolution in the fine grain area is explained by the specific grain boundary migration characteristics in the weaker inhibitor intensity, namely, the texture evolved has closer relationship with the product of the intensity of its own and the frequency of the grains in Σ9 orientation relationship in the primary matrix.View full abstractDownload PDF (1027K) -
Masamichi Miki, Yoshikiyo Ogino1990 Volume 54 Issue 4 Pages 388-395
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of the grain size on the nucleation and growth of grain boundary cells in Cu-2%Be and Cu-10%Ni-8%Sn alloys were investigated by the quantitative metallographic method. The nucleation of the cells was suppressed with increase in the mean grain size. The maximum growth rate of cell at the early stage of aging depended on the mean grain size and was maximum in the specimen with intermediate grain size, 160 μm in the Cu-2%Be alloy and 110 μm in the Cu-10%Ni-8%Sn alloy. The mean growth rate of cell was also dependent on the grain size, but the degree of its dependence was not so remarkable in comparison with that of the maximum growth rate of cell. The volume fraction of the cell decreased with increase in the grain size. The nucleation and growth of cells in the Cu-10%Ni-8%Sn alloy were more remarkably influenced by the grain size in comparison with those of the Cu-2%Be alloy.View full abstractDownload PDF (2353K) -
Masamichi Miki, Yoshikiyo Ogino1990 Volume 54 Issue 4 Pages 396-402
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of Si addition on the nucleation and growth of the grain boundary cell in a Cu-10%Ni-8%Sn alloy on aging at 723 K after quenching from 1123 K were investigated by means of hardness measurements, optical and electron microscopic observations, and X-ray analysis. The addition of Si retarded the precipitation of the γ′ phase in the matrix and suppressed the nucleation and growth of grain boundary cells. In the case of Si additions more than 0.4%, the cell was scarcely observed even after the long time aging. Very fine particles of Ni31Si12 phase were observed in the matrices and grain boundaries of the as-quenched specimens containing more than 0.4% of Si. Therefore, these fine particles in the grain boundaries must have occupied the nucleation sites of a γ((Cu·Ni)3Sn) phase and resulted in the suppression of the nucleation of the cells which consisted of lamellar mixtures of the γ and α phases.View full abstractDownload PDF (1962K) -
Takehide Senuma, Hajime Saitoh, Kousaku Ushioda, Naoki Yoshinaga, Hiro ...1990 Volume 54 Issue 4 Pages 403-412
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSRecent development in the automobile industry requires higher and higher formability of steel sheets. With an aim of improving the deep drawability, the influence of α-region hot rolling on the texture and r-values of cold rolled Ti-bearing extra low carbon steel sheets has been investigated and the following results were obtained.
(1) As for steel sheets hot rolled in the α-region, recrystallization textures in the midlayer of the cold rolled and annealed sheets show, regardless of the recrystallized or the non-recrystallized state before cold rolling, higher ND\varparallel⟨111⟩ intensity, whose development is favorable for deep drawability, than that of conventional cold rolled sheets.
(2) If hot rolled sheets have a deformed microstructure, ND\varparallel⟨111⟩ in the surface texture after final annealing does not develop and the main orientation is near {113}⟨110⟩±15, while ND\varparallel⟨111⟩ in the surface recrystallization texture of the cold rolled and annealed sheets increases with increasing cold rolling reduction if a recrystallization treatment is carried out after α-region hot rolling, though the scale of the increase is less than conventional cold rolled sheets.
(3) In consideration of the nucleation and growth mechanism and employing a crystal rotation model, the formation of the recrystallization textures was discussed from a viewpoint of the stored energy and crystal rotation relationship around certain axis between the orientation of the recrystallized grain and that of the surrounded deformed matrix.
(4) In the case of steel sheets hot rolled in the α-region, cold rolled and annealed, the averall r-value is positively influenced by the midlayer texture and negatively by the surface texture.
The detrimental effect of the surface texture was reduced through the α-region hot rolling in a lubricated condition and a great increase in r-value was achieved. In this case, if the microstructure of the sheet before cold rolling is recrystallized, the average r-value is 0.5-0.8 higher than that of the conventional cold rolled sheets.View full abstractDownload PDF (1740K) -
Hisashi Kuwano, Iwao Sawai, Shoji Uchida, Yoshikazu Hamaguchi1990 Volume 54 Issue 4 Pages 413-419
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe isothermal transformation of austenite in a SUP6 steel has been investigated by means of Mössbauer spectroscopy. The amount of retained austenite and its carbon content are measured as a function of holding time at an annealing temperature.
Carbon content of retained austenite increases with time up to 1.8%, which may be overestimated by the thickness effect, during annealing at 723 K. The amount of retained austenite at room temperature changes linearly with carbon content of austenite. Retained austenite is formed when its carbon content exceeds about 1.0%. The decrease in carbon content and the amount of retained austenite is accompanied by the formation of χ-Fe5C2 carbide.View full abstractDownload PDF (906K) -
Michihiko Nagumo, Yukihiro Sawano1990 Volume 54 Issue 4 Pages 420-426
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe mechanism of ductile to brittle transition has been investigated with the V-notched Charpy test of a control-rolled low alloy steel.
(1) The absorbed energy is found to be in a unique correlation with the lateral expansion ratio of specimens irrespective of anisotropy of specimens, testing temperatures and scattering of energies. It means that the absorbed energy is determined by the amount of plastic deformation by bending, and that the change in the yield stress and the anisotropy of the specimen play a role through the critical amount of deformation.
(2) The fractographic observation indicates that a stretch zone is formed at the notch root, and that multiple activations of crack sources take place. Characteristics of the fracture surface features are common to different orientations of specimens.
(3) The dependence of the transition curve on the texture is strong on (110) rather than on (100).
(4) The above results imply that the transition behavior is closely associated with the plastic deformation prior to the onset of brittle fracture. It is suggested that the stress controlled mechanism for one fracture source activation is not appropriate, but that some intrinsic change in the matrix during the course of plastic deformation is essential for the transition behavior.View full abstractDownload PDF (2300K) -
Shinji Ando, Kazuki Takashima, Hideki Tonda1990 Volume 54 Issue 4 Pages 427-434
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe mechanism of anomalous temperature dependence of yield stress by {11\bar22}⟨\bar1\bar123⟩ second order pyramidal slip in Cd single crystals in proposed. (c+a) edge dislocations are immobilized as a result of thermally activated dissociation, i.e., (c+a)→>(c sessile dislocation)+(a basal dislocation). Increase in frequency of the immobilization with increasing temperature decreases the mean moving distance of (c+a) edge dislocations and consequently the amount of strain in slip bands. In order to maintain the constant strain rate at higher temperature, the velocity of slip band propagation by double cross slip of (c+a) screw dislocation to the next near slip plane must be increased by higher stress. Therefore, the yield stress increases with increasing temperature. The mean moving distance of (c+a) edge dislocation is nearly constant when the strain rate is increased. Then, the higher stress for increasing the slip band propagation velocity is needed to compensate for the increased strain rate. The yield stress, therefore, increases with increasing strain rate.
The negative temperature dependence of the yield stress below 133 K is considered to be caused by the deformation controlled by the Peierls mechanism.View full abstractDownload PDF (1376K) -
Masayuki Ohashi, Takao Endo, Taku Sakai1990 Volume 54 Issue 4 Pages 435-441
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInitial grain size effects on dynamic recrystallization (DRX) of pure nickel were studied by means of tensile testing and microstructural observation over the range of strain rates from 10−5 s−1 to 10−1 s−1 and at temperatures between 923 K and 1123 K. The flow curves were categorized in terms of three types of shapes; (i) single peak type at high Z (=\dotεexp(Q⁄RT)), (ii) multiple peak type at medium Z, and (iii) the third type which showed a sharp stress dip following a stress peak and then strain hardening with serrations in stress at lower Z. The grain structural changes by DRX as well as the flow curves were affected sensitively by initial grain size Do. The coarse grained sample was refined continuously during single peak flow until the stable size Ds was attained. The fine grained one underwent some grain refinement at the first peak strain, even though it eventually coarsened up to the same size Ds during multiple peak flow. The critical value of Zc (or the first peak stress σpc at Zc), at which the flow curve shape changed from multiple to single peak type, depended on Do. The relationship between σpc and Do approximately overlapped that of σp vs. 2Ds, and thus the critical condition in question was expressed by the relation of Do=2Ds. These results were analyzed by using the relative grain size model for DRX.View full abstractDownload PDF (2439K) -
Sumiko Sanuki, Norio Minami, Koichi Arai, Toshio Izaki, Hiroshi Majima1990 Volume 54 Issue 4 Pages 442-447
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe acid leaching for copper anode slime in dilute acid solutions and the oxidative leaching behavior of the acid leach residue sample in a nitric acid solution containing sodium chloride have been investigated from both a thermodynamic consideration and an experimental study based on the results obtained on the leaching rates, the stoichiometry of the leaching reaction and the X-ray diffraction analysis of the leaching products. The main results obtained are summarized as follows:
(1) The pre-treatment of Cu-anode slime by using an acid leaching technique is effective, and the precious metals such as Au, Ag and Pt remain in the acid leach residue. However, Cu and Pb are easily dissolved under the acidic conditions, and this tendency coincides with thermodynamic considerations.
(2) The oxidative leaching for the acid leach residue of Cu-anode slime in a nitric acid solution containing sodium chloride is fast, and the leaching rate increase with an increase in the concentractions of sodium chloride and nitric acid in the leaching solution. The precious metals such as Au, Pt and Pd are dissolved into the leaching solution. However, Ag remains as AgCl in the oxidative leach residue.
(3) From the experimental results obtained, the optimum leaching conditions are as follows. The concentrations of sodium chloride and nitric acid in the leaching solution are 2 kmol/m3 and 1 kmol/m3, respectively, and the mass of the acid leach residue sample is below 10 kg.View full abstractDownload PDF (833K) -
Yorimasa Takeda, Masahiro Saito1990 Volume 54 Issue 4 Pages 448-457
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to evaluate the role of hydrogen and anodic dissolution on the stress corrosion cracking of 5%NiCrMoV steels, stress corrosion cracking tests on the specimens with wide range of temper embrittlement were carried out in a boiling 60%Ca(NO3)2 solution, a boiling 40%NaOH solution and a H2S-saturated 0.5%CH3COOH solution (at room temperature). The effect of temper embrittlement and the role of hydrogen on the stress corrosion cracking were discussed in terms of fracture morphology compared with the hydrogen induced cracking in hydrogen gas.
The stress corrosion cracking in the 40%NaOH solution at open circuit potentials and in the H2S-saturated 0.5%CH3COOH solution could be explained by hydrogen, while the stress corrosion cracking in the 60%Ca(NO3)2 solution and in the 40%NaOH solution at −400 mV (vs Ag/AgCl/sat.KCl) was related to anodic dissolution.View full abstractDownload PDF (3942K) -
Motoi Hara, Katsuji Takahara, Yutaka Shinata1990 Volume 54 Issue 4 Pages 458-465
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe hot corrosion behavior of nickel under cathodic polarization in molten Na2SO4 has been investigated by the measurement of corrosion loss, the observation of corrosion morphology and the analysis of corrosion product. Corrosion loss of nickel under cathodic polarization in molten Na2SO4 increased remarkably with an increase in the quantity of electricity for cathode reaction. On the contrary, the corrosion loss of nickel under cathodic polarization in molten NaCl was independent of the quantity of electricity for cathode reaction and was small. The feature of severe attack was observed for the surface of nickel after cathodic polarization in molten Na2SO4. A large amount of powdered corrosion product was detected in Na2SO4 melt after cathodic polarization. Such a corrosion product was found to consist of Ni and NiO from X-ray diffraction analysis. The cathodic polarization reaction and the reaction products were examined in order to discuss a mechanism for cathodic corrosion for nickel in molten Na2SO4. As a consequence, it was found that a two-electron reaction in which SO42− was a reactant occurred and O2− was produced by the reaction. It was considered on the basis of these facts that the corrosion of nickel under cathodic polarization in molten Na2SO4 proceeded mainly as an association of nickel with O2− and SO2 which were cathodic products.View full abstractDownload PDF (1207K) -
Takayuki Nishi, Toshio Oishi, Katsutoshi Ono1990 Volume 54 Issue 4 Pages 466-472
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTrace amounts of oxygen around 1 mass ppm in pure copper were determined by an inert gas fusion infrared absorption method.
In this study, the following pretreatments for the graphite crucibles and the copper samples were introduced in the analysis of trace amounts of oxygen.
During the oxygen analysis, some residual gases were cared to come out from the crucible, which was used for the oxygen extraction in the impulse furnace, even after purging in that furnace. To decrease these gases, the graphite crucibles were degassed beforehand for 7.2 ks in a vacuum furnace at the pressure of 10−2 Pa and the temperature of 2000 K. The variation in the blank values was decreased by that operation, and the detection limit evaluated from the blank values was 0.3 μg/g.
Furthermore, the excess oxygen on the surface of the copper sample was also removed as much as possible. Before the copper sample was dropped into the graphite crucible for the extraction furnace, the surface of it was reduced under a stream of 5%H2-Ar mixing gas at 673 K for 600 s. Secondary ion mass spectrometry (SIMS) showed that hydrogen reduction treatment did not effect the oxygen concentration in the bulk.
As a result of those pretreatments, the analytical values of oxygen in copper and their standard deviations were lower than those without them.
The pretreatments mentioned above were, therefore, found to be effective for the analysis of the trace amounts of oxygen in copper.View full abstractDownload PDF (1082K) -
Yasunori Harada, Masanobu Ohmori, Shin-ichi Ohnishi1990 Volume 54 Issue 4 Pages 473-479
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe workability of cast pure chromium produced by an induction-slag-melting process was investigated through the study of rolling and isothermal upsetting. The cast material had large crystal grains elongated along the cylindrical ingot axis or the solidification direction. The effect of rolling, which was performed to change the coarse cast structure to a finer one, on the ductile-to-brittle transition temperature (DBTT) was also examined. The present results are summarized as follows.
DBTT of the as-cast specimen tested in tension at a strain rate of 2.4×10−2 s−1 was about 500 K. A minimum ductility and a maximum flow stress appeared at about 973 K owing to dynamic strain aging.
The forming limit in upsetting, percent reduction of height at beginning of cracking on the specimen wall, increased to 80% at 773 K, and no crack appeared at temperatures above 873 K.
At all temperatures, there occurred cracks in the as-cast specimen deformed by a conventional rolling. Cracks occurred slightly in the specimen even in a sandwich-rolling by which a sintered chromium was successfully deformed. Cracking in the as-cast specimem was mainly due the coarse structure with large crystal grains. Once the structure was changed to a finer one by the upsetting, the specimen was easily rolled to a thin sheet without crack occurrence.
DBTT of the specimen rolled to 80% and followed by annealing at 1273 K was higher by about 200 K than that of the as-cast specimen, while annealing at 1473 K yielded a slightly lower value than that of the ascast material.View full abstractDownload PDF (2318K) -
Hitoshi Nakamura, Masahiro Kitada1990 Volume 54 Issue 4 Pages 480-484
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of impurities and deposition condition on the electrical resistivity of titanium thin film is investigated. The titanium thin films are deposited by a conventional electron beam system in a vacuum of 10−8∼10−4 Pa. The purities of the titanium deposition sources used are 3N (99.9 mass%Ti), 4N (99.99 mass%Ti; O2∼300 ppm) and 4N up (99.99 mass%Ti; O2<200 ppm). The substrate temperature is 473 K and the deposition rate is 0.5∼0.7 nm/s. The thickness of titanium thin films is 150 nm. The electrical resistivity of titanium thin films is measured by the four-probe method. The impurity contents in titanium thin films are measured by SIMS. The results are as follows. The electrical resistivity of titanium thin films decreases with increasing vacuum pressure and decreasing impurity content. The average grain diameter of titanium thin films deposited in a vacuum of 10−8∼10−4 Pa using the same source increases with increasing vacuum pressure. The contribution of grain boundary scattering to the electrical resistivity is analyzed using the Mayadas and Shatzkes’s equation. As a result, it is found that the vacuum pressure causes a change in grain diameters, thus affecting the electrical resistivity of titanium thin films. Moreover, a good relationship is obtained between the electrical resistivity subtracted the contribution of grain boundary scattering and the oxygen content in titanium thin films. On the other hand, the average grain diameter of titanium thin films deposited in the same vacuum using different sources increases with decreasing impurity content. It is thought that the electrical resistivity of titanium thin films deposited using different sources is influenced by the oxygen content and other impurity metal contents in the deposition sources, except for the contribution of grain boundary scattering.View full abstractDownload PDF (1356K) -
Naoji Nakamura, Yuetsu Murakami, Nobukiyo Kobayashi, Seishi Abe1990 Volume 54 Issue 4 Pages 485-492
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMagnetic properties of Fe-Mo-W alloys containing equivalent amounts of less than 6 mass%Mo and less than 6 mass%W were studied. The specimens of fine wires 0.5 mm in diameter used were prepared by cold-drawing to 50∼99% reduction in area after melting in vacuum and subsequent water-quenching from 1173-1373 K. Subsequently, all the fine specimens were reheated at 673-1273 K for the durations less than 18 ks.
It is found that the workability of Fe-Mo-W alloys depends largely on the [Mo+W] content and the reduction in area by cold-drawing. The magnetic properties also depend largely on the [Mo+W] content, water-quenching temperature, reduction in area and reheating treatment. The magnetic behavior of Fe-Mo-W alloys are generally similar to that of Fe-Mo and Fe-W alloys. Moreover, at the composition of less than 8 mass%[Mo+W], both the magnetic induction B8 at 8 kA·m−1 and the residual induction Br were higher than those of the Fe-Mo and Fe-W alloys. The coercive force Hc shows an intermediate value between those of the Fe-Mo and Fe-W alloys. The thermal expansion coefficient near room temperature, αT, were lower than those of the Fe-Mo and Fe-W alloys.
The Fe-3%massMo-3%massW alloy reheated at 873 K for 18 ks after water-quenching from 1273 K and subsequent cold-drawing to 99% reduction exhibited B8=1.91 T, Br=1.88 T, Hc=1.55 kA·m−1, the squareness ratio Br⁄B8=0.93, the squareness factor \sqrt(BH)max⁄BrHc=0.86 and αT (273−673 K)=11.7×10−6 K−1.View full abstractDownload PDF (1634K) -
Fukuji Inoko, Minoru Tagami, Takashi Yoshikawa1990 Volume 54 Issue 4 Pages 493-494
Published: 1990
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (330K)
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