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Volume 50, Issue 7
Displaying 1-13 of 13 articles from this issue
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Tohru Yamasaki, Yoshikiyo Ogino1986 Volume 50 Issue 7 Pages 595-601
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to obtain informations about the compositional dependence of temper embrittlement of Fe-B-Si and Fe-P-Si amorphous alloys, simple bend properties, X-ray diffraction and DSC spectra of as-quenched and annealed specimens were examined. In both of the above systems, a high embrittlement susceptibility has been observed, when the composition is located in a hypereutectic region. While, when the composition is located near a eutectic or in a hypoeutectic region, the embrittlement susceptibility drastically decreases, e.g., an Fe79.5B12Si8.5 amorphous alloy having a near eutectic composition remains ductile until crystallization. On the other hand, the embrittlement does not correlate with the degree of phase separation estimated from X-ray diffraction and the amount of heat released during structural relaxation.View full abstractDownload PDF (1437K) -
Kei Ameyama, Tadashi Maki, Imao Tamura1986 Volume 50 Issue 7 Pages 602-611
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe morphology and the crystallographic features of austenite (γ) precipitated at ferrite (α) grain boundaries have been investigated using Fe-25Cr-6Ni two-phase stainless steel. The starting structure of the alloy before aging in (α+γ) two-phase region was fully ferritic. The γ precipitation at high angle α grain boundaries (G.B.γ) was found to be classified into three main types according to the morphologic and the crystallographic feature; Type I consists of γ particles having the same variant of K-S orientation relationship (O.R.) and shows a film-like morphology by coalescence of these γ particles. Type II consists of γ particles of different K-S variants, showing an allotriomorph morphology by impingement of the γ. The γ of these two types are both holding K-S O.R. to only one of two adjacent α grains, not to the other. Type III consists of γ particles having the same orientation, the close-packed plane of γ being in parallel to those of both α grains, and shows a film-like morphology by coalescence of the γ.
The close-packed α planes which are in parallel relationship between G.B.γ and α grain in these three types were found to be nearly parallel to the plane of the grain boundary. In the case of Type I, only one K-S variant of γ was selected by taking most coherent orientation against unrelated α grain. The γ of Type II, however, was able to select 4 different K-S variants of the same close-packed parallel orientation relationship, for lack of coherent orientaion against unrelated α grain. For this reason the morphologic and the crystallographic feature of G.B.γ strongly depend on the orientation of α grain boundary plane. Also the morphologic and the crystallographic feature of spike-γ growing from G.B.γ depend on the α grain boundary orientation because of strong correlation among spike-γ, G.B.γ and α grain.View full abstractDownload PDF (3477K) -
Toshiyuki Matsunaga, Yukitomo Komura1986 Volume 50 Issue 7 Pages 611-615
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA new MgCu2 type ordered phase which we found in the Mg-Cu-Si ternary system belongs to the space group P4132 or P4332. The structure is characterized by the ordered 4-fold screw arrangement of Cu and Si atoms situated at 12d and 4a sites respectively, forming four small tetrahedra in the unit cell. Intensity data for a spherical single crystal of Mg(Cu0.8Si0.2)2.4 were recollected and structural parameters together with the order parameter S were refined by a full-matrix least squares method. Twenty alloy specimes having different compositions in the ternary system were studied by the powder X-ray diffraction method, in order to determine the existence range of the new ordered structure. The order parameters for the specimens quenched from 473-893 K were estimated at room temperature by using Warren’s method. The order parameters were corrected by a successive approximation, taking into account of the atomic shifts due to ordering. The order parameter S thus obtained decreases continuously with increasing annealing temperature T, and the S-T curve obtained can be expressed by the formula, S=D(Tc−T)β.View full abstractDownload PDF (740K) -
Hideharu Nakashima, Hideo Yoshinaga1986 Volume 50 Issue 7 Pages 616-624
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to clarify the deformation mechanism in the transient creep region, the instantaneous plastic strain and the strain rate have been measured precisely by using pure aluminum from a very early stage of transient creep to the steady state. The creep test has been carried out at temperatures from 623 K to 823 K and at stresses from 0.81 to 6.7 MPa.
It is found that the instantaneous plastic strain depends not on temperature but exclusively on stress. At a very early stage of transient creep, the Zener-Hollomon parameter, Z, depends strongly on temperature in the lower temperature region (623-723 K) but not on temperature in the higher temperature region (773-823 K). At the later stage, the Z vs. strain curve converges to a single one, which is the same as that in the higher temperature region, and finally comes into the steady state.
From the temperature-independence, it is concluded that the main part of instantaneous plastic strain is produced by the athermal motion of dislocations, and from the theroetical analysis based on a dislocation-network model it is inferred that the creep mechanism in the lower temperature region changes from a process, in which the thermally activated glide of some long dislocation links takes part, to the well-known recovery process at an early stage of transient creep.View full abstractDownload PDF (1315K) -
Hisakichi Sunada, Hisashi Izumi, Yukinobu Hayashi, Tsuyoshi Masumoto1986 Volume 50 Issue 7 Pages 624-630
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThis paper deals with the static and dynamic tensile properties of an amorphous Fe75Si10B15 wire at various temperatures and atmospheres. The wire has been produced by the in-rotating water spinning method, its diameter being about 126 μm. The main results are as follows:
(1) The tensile strength depends on the temperature and strain rate. The fatigue strength at higher temperature increases with rising temperature because of the superposed effects of the reducing humidity and the cyclic stresses causing a structure change.
(2) Since the tensile strength of the amorphous wire depends on the relative humidity of the air, the fatigue strength is especially low in comparison with the tensile strength.
(3) In air, the fatigue strength of the amorphous wire is lower than a commercial piano wire or a hard drawn steel wire. The fatigue life of the wire is improved in inert argon gas and nitrogen gas in this order.
(4) The fatigue fracture occurs on the surface due to uniform deformation. Any distinct striation pattern which characterizes fatigue fracture is not observed on the fracture surface.View full abstractDownload PDF (1730K) -
Masaki Kato, Miwako Imai, Koichi Arai, Toshio Izaki1986 Volume 50 Issue 7 Pages 631-639
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe feasibility of a new hydrometallurgical treatment process of battery slime was investigated. The process is composed of stages of the selective dissolution of PbSO4, the recovery of PbCO3 and the reductive leaching of PbO2. In this study, the process is discussed from a thermodynamic and a kinetic aspect based on the experimental results obtained on the leaching rates, the stoichiometry of the reactions and the X-ray diffraction analysis of the reaction products.
The main results are summarized as follows:
(1) The dissolution rate of PbSO4 in the solutions of DETA and CH3COONH4 is fast at the initial stage of the leaching, after which the rate decreases with increasing time. The solubility of PbSO4 increases with increasing concentration of leachants, and the solubility in DETA solution is about 10 times as large as that of CH3COONH4 solution. However, PbO2 is not reactive in the solutions of DETA and CH3COONH4, and thus a hydrometallurgical treatment based on the selective leaching of PbSO4 from the battery mud is possible.
(2) The precipitation rate of PbCO3 with Na2CO3 from the solutions of DETA and CH3COONH4 containing lead ions is very fast at the initial stage of the reaction, and then the rate decreases with increasing time. The precipitation rate of PbCO3 increases with increasing molar ratio of PbSO4/Na2CO3. Under the optimum conditions, PbCO3 recovery of 94% can be obtained in less than 1.8 ks at ambient room temperature.
(3) The conversion rate of PbO2 to PbSO4 with SO2 gas under the acidic condition increases with increasing partial pressure of SO2 gas and with increasing temperature of the solution, and the rate is very fast. From the experimental studies and thermodynamic consideration, it is concluded that the hydrometallurgical treatment of lead battery slime is possible.View full abstractDownload PDF (1117K) -
Katsuhiko Matsuda, Shosaku Toda, Hiroshi Majima1986 Volume 50 Issue 7 Pages 639-645
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe separation of Mo and V in a leach solution by solvent extraction using a basic extractant was studied for artificial solutions as well as industrial leach solutions containing both Mo(VI) and V(V), and a selective reduction-solvent extraction method, originally developed by the present authors, was found to be useful for this purpose. The principal results are as follows:
(1) Although Mo(VI) is stable in aqueous acidic solutions, V(V) is readily reduced to V(IV), which is less sensitive to solvent extraction. Solvent extraction of reduced aqueous solution resulted in a satisfactory separation of Mo from V. Although different acids or different reducing agents resulted in slightly different results, no interinsic difference in extraction characteristics was detected.
(2) Mo(VI) and V(V), both extracted in an organic phase, can be separated by stripping with artificial aqueous phase containing suitable reducing agents such as SO2 or its derivatives. The use of multi-stage stripping technology may allow complete separation.
(3) When the solvent extraction of leach solution containing both Mo(VI) and V(V) was performed in an autoclave under SO2 pressure, the transfer of Mo(VI) alone into an organic phase occurred. The separation of Mo from V was sufficient.
(4) The selective reduction-solvent extraction method was applied to the solution derived from the salting-out process to separate Mo and V. The Mo product (H2MoO4) and V products (NH4VO3 and VO(OH)2) produced from each separated solution were found to be substantially purer than those obtained by current methods.View full abstractDownload PDF (977K) -
Toshio Shimoo, Tsutomu Isobe, Shigeru Ando, Hiroshi Kimura1986 Volume 50 Issue 7 Pages 646-653
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn relation to the smelting reduction of chromite ore, the mechanism of reduction of aluminate slags containing about 40% of Cr2O3 by graphite has been investigated. The rate of reduction has been determined from the mass loss measured by means of thermogravimetry, and the physical situation of the reduction products formed at the slag-graphite interface has been examined by microscopic observation.
While the layer of the reduction product keeps intimate contact with the graphite, the rate of reduction obeys the parabolic rate equation. The rate constant is not affected by the ratio (%CaO)/(%Al2O3), and the activation energy is 229 kJ/mol. The rate is controlled by the diffusion of carbon in the product layer.
When the slag penetrates through cracks in the product and is brought into direct contact with the graphite, the reduction of chromium oxide is accelerated. The rate of reduction is approximately represented by the zeroth-order-type rate equation. The rate is independent of the ratio (%CaO)/(%Al2O3). For the slags with (%CaO)/(%Al2O3)=0.97 and containing Cr2O3 more than about 9%, the rate remains essentially unchanged with increasing initial content of Cr2O3. The apparent activation energy is 533 kJ/mol. It is supposed that the rate of reduction is limited by the solubility of chromium in slag.View full abstractDownload PDF (1856K) -
Kimiko Sakata, Tsuneo Ohkoshi, Kazuyoshi Nii1986 Volume 50 Issue 7 Pages 654-658
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSolid state bonding of carbon steel (written as Fe hereafter) and Al2O3 using Fe-FeO composite interlayers (written as I hereafter), and fabrication of Fe-FeO composite materials were carried out by hot pressing at 1450 K for 36 ks in a vacuum of 10−3 Pa under pressure of 29.3 MPa. The interface chemistry and the bonding strength related to Fe/I/Al2O3 systems were investigated by means of EPMA and an Instron testing machine. A complex oxide which consisted of Fe, Al and O, was formed at the Al2O3/I boundary region. A new reaction layer about 6 μm in thickness was formed in the boundary region in a similar way to the case of the Al2O3/FeO bonding. In the Fe/I boundary region, the Fe in the bulk united with Fe in the interlayer to form strong bonding. The tensile strength of Fe/I/Fe and Al2O3/I/Al2O3 systems had the values of 145 MPa and 135 MPa, respectively, when an Fe-25 mol%FeO interlayer was applied. The composition dependence curve of tensile strength for the Fe-FeO composite materials showed similar behaviour to that for the Fe/I/Fe systems. The Al2O3/I/Al2O3 systems showed the maximum tensile strength at 25 mol%FeO, and it rapidly decreased when the concentration of FeO decreases below 25 mol%. The 25 mol%FeO for the composite interlayer, therefore, was the optimum for the Fe/I/Al2O3 bonding.View full abstractDownload PDF (2661K) -
Yoshiaki Umehara, Shigeyasu Koda1986 Volume 50 Issue 7 Pages 659-665
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA eutectic alloy of InSb-Sb has been unidirectionally solidified at various rates of solidification, in order to investigate the structural change with the solidification condition.
The results as follows:
(1) The spacing λ of Sb rods was expressed to be linear to R−1⁄2, where R was the rate of solidification, and λ2R was 2.4×10−16 m3/s.
(2) The alloy specimens consisted of polycrystalline columnar grains which elongated to the solidification direction. The crystallographic orientation relationship between the InSb and Sb phases was determined by X-ray diffraction. A preferred relationship were observed can be stated approximately as follows:
Growth direction: ⟨110⟩InSb\varparallel⟨0001⟩, ⟨4 8 ‾12 1⟩ or ⟨24\bar6\bar1⟩Sb.
Crystallographic plane: {110} or {111}InSb\varparallel{11\bar20}, {01\bar14} or {01\bar1\bar8}Sb.
(3) The interfacial energies between the InSb and Sb phases were calculated from a dislocation model considering the mismatch at the interface to be equal to 1.25-1.88 J/m2. According to the value of interfacial energy and the microscopic observation, it seems that the side direction of Sb triangles is parallel to ⟨10\bar10⟩Sb.
(4) Assuming that the crystal growth follows Jackson’s model, and also using the above-mentioned phase boundary energy, the diffusion coefficient of Sb in molten InSb-Sb eutectic alloy was evaluated as D=1.6×10−9 m2/s.View full abstractDownload PDF (3007K) -
Yoshiaki Umehara, Shigeyasu Koda1986 Volume 50 Issue 7 Pages 666-670
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA eutectic alloy of GaSb-CrSb has been unidirectionally solidified at various rates of solidification, in order to investigate the structural change with the solidification condition.
The results are as follows:
(1) The spacing λ of CrSb rods was expressed to be linear to R−1⁄2, where R was the rate of solidification, and λ2R was 1.52×10−16 m3/s.
(2) The alloy specimens consisted of polycrystalline columnar grains which elongated to the solidification direction. The crystallographic orientation relationship between the GaSb and CrSb phases was determined by X-ray diffraction. A preferred relationships were observed can be stated approximately as follows:
Growth direction: ⟨110⟩GaSb\varparallel⟨0001⟩CrSb.
Crystallographic plane: {110}GaSb\varparallel{10\bar10} or {11\bar20}CrSb.
(3) The interfacial energies between the GaSb and CrSb phases was determined from a dislocation model considering the mismatch at the interface to be equal to 1.06-1.66 J/m2. Assuming that the crystal growth followed Jackson’s model, and also using this phase boundary energy, the diffusion coefficient of CrSb in molten GaSb-CrSb eutictic alloy was evaluated as D=1.6×10−9 m2/s.View full abstractDownload PDF (2311K) -
Naotsugu Inakazu, Akifumi Yamaguchi1986 Volume 50 Issue 7 Pages 671-677
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe forming process of drawing texture and the recrystallization behavior of (α+β) brass rod have been investigated by means of determination of the ODF and transmission electron microscopy.
The preferred fiber component is composed of the ⟨111⟩+⟨100⟩ duplex fiber texture which is less in intensity than that of α mono-phase brass rod because of the presence of β-phase. The fiber component in β-phase is composed of the ⟨110⟩ fiber texture which is a stable orientation in bcc metals. The volume fraction of β-phase increases with the increase of the drawing ratio and reaches about 40% by drawing to 90% reduction, because the distorted β′-phase and fct α1-phase are developed during deformation.
Regarding the recrystallization behavior, the ⟨111⟩ fiber texture remains in α-phase, and the ⟨110⟩ fiber texture remains in β-phase with the continuous recrystallization.
Microscopic examination shows that the α-phase bulges into the β-phase on annealing.View full abstractDownload PDF (1494K) -
Yasunori Miyata, Toshio Suzuki1986 Volume 50 Issue 7 Pages 678-679
Published: 1986
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (633K)
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