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Volume 41, Issue 1
Displaying 1-17 of 17 articles from this issue
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Teruo Kiyosawa, Katashi Masumoto1977 Volume 41 Issue 1 Pages 1-7
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to obtain basic information for a physico-chemical understanding of the deviation from the stoichiometry in the ferromagnetic semiconductor CdCr2Se4, a PSe2−T diagram for the stability of the compound was determined for the first time by annealing experiments under controlled Se2 and Cd vapor pressure in the temperature range 800∼964°C. It was compared with the equilibrium phase diagram in the CdSe-Cr3Se4-Se system, as a region in the Cd-Cr-Se ternary system related to CdCr2Se4. The following characteristic features are clarified.
(1) The maximum temperature of the stability region of CdCr2Se4 in the PSe2−T phase diagram is about 900°C, which corresponds to the peritectoid reaction temperature already disclosed in the CdSe-Cr2Se3 pseudo-binary system.
(2) CdCr2Se4 is in equilibrium with Se-rich melt which has appreciable solubility of CdCr2Se4 at 880∼900°C and with substantially elementary Se below this temperature.
(3) The Cr-Se system compounds in equilibrium with CdCr2Se4 are only Cr2Se3 at temperatures above a certain temperature in the range 840∼860°C and Cr3Se4 in addition to Cr2Se3 below that temperature.View full abstractDownload PDF (633K) -
Kenzaburo Kumada, Kazumitsu Shinohara, Kengo Kawano, Toshihiro Seo1977 Volume 41 Issue 1 Pages 7-11
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe oxidation behavior of pure chromium was observed in situ while specimens were heated by means of a hot stage in a transmission electron microscope. The chromium oxides were found to show a marked difference in morphology with temperature. At 540°C the oxide grew mainly in a columnar form having a specific crystallographic relationship with the matrix chromium, but at 700°C it grew in random orientations. The columnar oxide at the lower temperature was oriented with its (1\bar10) plane parallel to the (1\bar10) plane of the matrix. The observed diffraction patterns suggest that a considerable amount of strain may be present at the interface between the columnar oxide and the matrix chromium. In addition, the oxide was found to grow most easily on {100} planes of the chromium matrix.View full abstractDownload PDF (708K) -
Manabu Tanaka, Ohmi Miyagawa, Dai Fujishiro1977 Volume 41 Issue 1 Pages 11-20
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of carbon and nitrogen contents on the grain boundary reaction has been investigated in steels with a base composition of 21%Cr-4%Ni-9%Mn-bal.Fe. In steels containing about 0.9 wt% of carbon plus nitrogen, the increase in nitrogen content enhanced remarkably the grain boundary reaction and suppressed the intragranular precipitation, while the increase in carbon content gave an opposite effect and enhanced the precipitation in the matrix. In steels containing various amounts of carbon and nitrogen, increase in both nitrogen and carbon contents enhanced the reaction, but nitrogen was much more effective than carbon. The nodules of the reaction were observed in steels containing more than 0.5 wt% nitrogen even though no carbon was added, but they could not be detected in steels containing less than 0.1 wt% nitrogen no matter how high the carbon content of steels was.
The effect of other alloying elements has also been investigated in a commercial 21-4N steel. They were classified in three groups. Only 0.5 wt% addition of Nb suppressed considerably the reaction and enhanced the intragranular precipitation which caused a decrease in supersaturation of carbon plus nitrogen in the matrix and an increase in pinning force. Both Mo and W had the same effect as Nb and therefore 1 wt% of Mo or W was effective to suppress the reaction. The grain boundary reaction was also suppressed by 13 wt% of Mn or 0.5 wt% of Cu which raised the solubility of carbon plus nitrogen in the matrix. A very small addition of B was effective to suppress strongly the reaction.View full abstractDownload PDF (1261K) -
Noboru Yahata, Fusao Hayama1977 Volume 41 Issue 1 Pages 21-26
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSWear experiments were performed on 0.42%C carbon steel quenched and tempered to various hardnesses. The wear tests were carried out by the pin-on-ring machine under an unlubricated condition in air. Metallurgical structures, oxidation, hardening or softening and residual stresses were examined in the sliding surface during the steady wear process, and the relation between wear rates and these properties was discussed.
The results obtained are as follows:
(1) The hardening by quenching is useful only in the range of low and moderate sliding speeds. In particular, it is noted that the specimens quenched and tempered to Hv 319 or more give mild wear at a moderate sliding speed at which the softer ones give severe wear.
(2) The transition speed at which the wear rate increases considerably at high sliding speed is approximately constant regardless of the hardness of specimens.
(3) FeO layers or continuous hard layers always appear in the vicinity of the sliding surface when the seizure occurs. The sliding speed for its appearance decreases with increase in hardness.
(4) The sense and magnitude of the residual stresses in the sliding surface can be explained qualitatively in terms of the mechanical and thermal sources. Therefore, these can be mainly determined by the sliding condition.View full abstractDownload PDF (1139K) -
Hiroyasu Mitani, Hiroshi Nagai, Mikio Fukuhara1977 Volume 41 Issue 1 Pages 27-32
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSynthesis of ultra-fine TiC powders by vapor phase reaction between TiCl4 and CH4 in Ar plasma jet was investigated. The obtained TiC powders were single crystals and the particle size was in the range of 100∼1500 Å, which can be controlled by changing the concentration of reactant gas and plasma jet power. The lattice parameter of TiC powders obtained was constant, being 4.327 Å regardless of the experimental conditions. Free carbon and oxygen contents in the products can be decreased by increasing the plasma jet power and purifying the reactant gases. The best result was obtained at a plasme jet power of 2.4 kW and H2/CH4=3 using purified reactant gases. Under this condition, the combined carbon, free carbon and oxygen contents of the products were 19.57, 0.92 and 0.98 wt%, respectively. Electronic temperature of Ar plasma jet measured by the Langmuir double probe method was 15600°K at the center and 7600°K at the edge of the plasma jet flame.View full abstractDownload PDF (592K) -
Hideo Tai, Shigenori Hori1977 Volume 41 Issue 1 Pages 33-37
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMutual solubility and band gap energy (Eg) as a function of composition for the (CdTe)1−x-(ZnSe)x system were determined by X-ray diffraction and diffuse refrectance measurement. The results are as follows.
(1) X-ray diffraction study showed that CdTe and ZnSe were completely missible above 733°C, but two phases separation took place below this temperature. Two-phase ranges were found to be 0.20<x<0.85, 0.31<x<0.82, and 0.52<x<0.75 at 500, 600 and 700°C, respectively. Peak position of the missibility gap was estimated to be x=0.68±0.05 and 733±10°C.
(2) The dependence of Eg on composition for the (CdTe)1−x-(ZnSe)x solid solution annealed at 900°C was found to deviate downward from linearity.
(3) The following equation for the composition dependence of the Eg of the (CdTe)1−x(ZnSe)x system was derived from the experimental Eg data of the CdTe-ZnTe, CdSe-ZnSe, CdTe-CdSe, and ZnTe-ZnSe systems.
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\ oindentthis equation is in good agreement with experimental data for the (CdTe)1−x-(ZnSe)x system within an error of 4%.View full abstractDownload PDF (393K) -
Kikuo Nakano, Hiromi Matsubara, Toru Imura1977 Volume 41 Issue 1 Pages 38-44
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe Knoop hardness measurements from room temperature to 1100°C were made on (0001), {10\bar10} and {11\bar20} planes of TiB2 single crystals grown from iron, cobalt and nickel solutions. Changes in hardness anisotropy with temperature, the temperature dependence of the thermal softening coefficient, and the influence of the solvent on the hardness were discussed.View full abstractDownload PDF (766K) -
Hiroshi Nakai, Toshiro Kuji1977 Volume 41 Issue 1 Pages 45-49
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe initial growth of nickel-sulphide formed on the (100), (110) and (111) planes of single crystals in low-pressure H2S and H2-H2S atmospheres was studied by electron microscopy. Sulphidation was carried out at 100 to 500°C.
Main results are as follows:
(1) The sulphide formed on the specimen was heazlewoodite Ni3S2.
(2) Increasing of thickness of sulphide scale, lowering of sulphidation temperature and increasing of H2S pressure led crystals of sulphide to disorientation.
(3) At low temperatures (≤300°C) the direction of Ni3S2 [1\bar101] was perpendicular to the surface of the nickel crystal at an early stage, consisting of a combination of two kinds of orientations equivalent and symmetrical to each other. This was explained on the assumption that the chemisorbed layer formed on a clean surface of Ni is the immediate substrate for the growth of Ni3S2. But this relationship at an early stage disappeared as the sulphide scale grew.
(4) At high temperatures (≥400°C) the above relationship didn’t appear and the plane of Ni3S2 (00·1) was parallel to the surface of Ni.View full abstractDownload PDF (530K) -
Masanori Ueki, Tadahisa Nakamura1977 Volume 41 Issue 1 Pages 50-54
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe dynamic recrystallization phenomenon during hot torsion of OFHC copper was investigated from various view points such as the flow stress behaviour, the grain refinement effect and the mechanism of recrystallization. The general characteristics of the stress-strain curves were to exhibit a marked peak, after which the flow stress decreased to a steady state value. A feature of the curves at low strain rates was the regular oscillation of flow stress during the initial stages of deformation. This is a deformation behaviour characteristic of dynamic recrystallization type materials.
There was a knee point on the plot of the relationship between the steady state flow stress and the Zener-Hollomon parameter (Z) at the condition of Z\simeq1012 sec−1, and from the results of microstructural observations at each deformation condition (Z value), it was understood that the equiaxed grain structure due to dynamic recrystallization was obtained in the Z value lower than this knee point. In this condition of Z lower than 1012 sec−1, the larger the Z value the finer became the dynamically recrystallized grain, and hence the value of Z nearly equal to 1012 sec−1 was the optimum deformation condition for the grain refinement by dynamic recrystallization. Furthermore, it was shown that there was a quantitative relationship between the dynamically recrystallized grain diameter (D) and the logarithm of Z as follows: D−1(μm−1)=−0.054+0.008logZ.
According to the results by transmission electron microscopy, it could be deduced that the mechanism of the dynamic recrystallization was based on the formation of recrystallized nuclei by bulging the localized area of the grain boundaries.View full abstractDownload PDF (658K) -
Toshihei Misawa, Kohei Tsuji, Hideo Sugawara1977 Volume 41 Issue 1 Pages 55-62
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA study has been made of the corrosion fatigue in 70Cu-30Zn brass in an ammoniacal copper sulphate solution at 25°C. The effects of pH on the fatigue strength, crack propagation and the nature of cracking are investigated in comparison with those obtained in the silicone oil reference environment and also with the situation of stress corrosion cracking.
The corrosion fatigue behaviour was found to be strongly dependent on pH. A minimum in corrosion fatigue life or strength was observed in a neutral tarnishing solution of pH 6.5 to 7.0. Fractographic examination showed that intergranular cracking predominated in both neutral tarnishing and acidic non-tarnishing solutions, and transgranular cracking with striations occurred in an alkaline solution. The tarnish film is considered to be of importance only in providing the protection of the specimen surface and the cracked interface and promoting the dissolution at the propagating crack tip.View full abstractDownload PDF (1141K) -
Y\={o}ichi Ono, Tatsuhiko Shigematsu1977 Volume 41 Issue 1 Pages 62-68
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDiffusion coefficients of vanadium, cobalt, and molybdenum in molten iron were determined by the diffusion-couple method with the following results:
For Fe-V alloy with vanadium content up to 1.42%
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for Fe-Co alloy with cobalt content up to 3.9%
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for Fe-Mo alloy with molybdenum content up to 1.04%
(This article is not displayable. Please see full text pdf.)
The close correlation which was found previously by the present authors between the diffusivity Dj and the standard free energy of solution of the diffusing element in molten iron ΔFj0 has proved to apply to the present results.View full abstractDownload PDF (575K) -
Tohru Arai, Yoshihiko Sugimoto, Noboru Komatsu1977 Volume 41 Issue 1 Pages 68-72
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn a previous paper, it was reported that carbide layers such as VC, NbC, Cr7C3, etc. can be formed on steels immersed in a borax bath containing metallic powder such as Fe-V, Fe-Nb or Cr.
The present study was undertaken to investigate the possibility of carbide formation on various kinds of steels immersed in a borax bath containing electrolytically dissolved V, Nb, Cr or Ta.
The results obtained are as follows:
(1) Carbide layers were formed on steels immersed in a bath containing electrolytically dissolved V, Nb or Cr.
(2) Even in a bath prepared by adding powders, carbide layers are considered to be formed by the reaction between carbon in steel and dissolved V, Nb or Cr in a bath from Fe-V, Fe-Nb or Cr powders, because the thickness of the carbide layers is almost the same under the same temperature and time in the baths containing carbide forming metal either electrolytically dissolved or added in powder form.
(3) In a borax bath containing dissolved Ta, double layers with outer Ta carbide and inner iron boride or boro-carbide layers are formed on steels, possibly because B2O3 may be reduced to B by Ta.View full abstractDownload PDF (554K) -
Hiroyasu Araki, Hisao Tanikawa, Yoshinori Fujimura1977 Volume 41 Issue 1 Pages 73-79
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to investigate the recrystallization of Cr-Ni austenitic steels from a fundamental point of view, the microstructural change with 1 hr annealing was studied on ten kinds of single phase specimens with 15∼25% Cr and 20∼35% Ni, which were cold rolled 75%, and also on single phase 20Cr-30Ni steel with different grain sizes and tensile strains. The results obtained are as follows.
(1) A small amount of hardening was observed prior to the onset of softening on the hardness-temperature curves for the cold-rolled specimens, which was regarded as originating from the strain aging. The softening after recrystallization became slower at high temperature, where optical microstructures exhibited a nearly uniform grain size distribution except the two kinds of cold-rolled specimens with 25% Cr and a small amount of Ni in which the σ phase formed. (2) Both the beginning and ending temperatures of softening for the cold-rolled specimens did not change with Ni content, but became higher as the Cr content increased. The following linear relationship was obtained between the ending temperature of recrystallization TR and the Cr content in weight percentage. TR=540+8×Cr (°C) . (3) The beginning and ending temperatures of remarkable softening for specimens tensile strained up to 40% were became lower as strain increased and grain size decreased. (4) Fine recrystallized grains nucleated near grain boundaries in the tensile deformed specimens, while in the cold-rolled specimens they nucleated in the deformation bands. (5) Recrystallization of heavily cold-worked single phase Cr-Ni anstenitic specimens can be regarded as starting from the formation of subgrain, followed by the nucleation of fine recrystallized grains inside the deformation bands, and ending in the disappearance of the areas of deformed structure outside the bands, where no subgrain is formed, by the growth of these recrystallized grains.View full abstractDownload PDF (1288K) -
Kazuo Suzuki, Tsutomu Okutomi, Satoru Mito1977 Volume 41 Issue 1 Pages 80-86
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInternal oxidation experiments of Cu+Misch Metal eutectic alloys and Cu+Al solid-solution alloys were carried out using the Rhines packing method at 550 to 850°C for 1 to 100 hr under the oxygen partial pressures of decomposition of Cu2O. Tensile properties of internally oxidized specimens are then measured using MICROMACHINE type Mi-34. Relationships between tensile properties and internal oxidation conditions are measured and discussed with respect to the internal oxidation thickness (=penetration depth: P), assuming that the specimen is composed of two-layered composite materials. Finally, oxidation mechanism of the above-mentioned alloys is analyzed and the activation energies for internal oxidation and diffusion of oxygen, Q1 and Q2 are calculated using the Arrhenius equation. The results obtained are summarized as follows:
(1) Proof stress of internally oxidized eutectic alloys (Cu+Misch metal) are decreased with increasing oxidation time and temperature and dispersion-hardening effect could not be observed.
(2) Measured proof stress of internally oxidized specimens is in good agreement with the strength calculated based upon two-layered composite materials.
(3) Internal oxidation processes are controlled by the diffusion of oxygen and have the activation energies of 40 kcal/mol for Cu+Misch metal alloys and of 53 kcal/mol for Cu+Al alloys.View full abstractDownload PDF (923K) -
Tatsuhiko Ejima, Toshinobu Yok\={o}, Kazutaka Nakashima1977 Volume 41 Issue 1 Pages 86-93
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe viscosity of ZnCl2-AlkCl binary systems has been accurately measured by means of the rotating cylinder method within the temperature range 260 to 560°C. The results obtained are summarized as follows:
(1) The viscosity of pure molten ZnCl2 exibits the non-Arrhenius behavior which can be divided into three stages within a temperature range from 320 to 560°C. The two stages on the high temperature side exibit an almost complete Arrhenius behavior. The constituent species corresponding to each stage have been estimated from the experimental results of this investigation and from those obtained by other authors.
(2) With the addition of alkali chlorides having the ionic character to pure molten ZnCl2, the viscosity and the apparent activation energy for viscous flow decrease drastically. This rate of decrease increases according to the following sequence: LiCl<NaCl<KCl<CsCl. However, the differences in the behavior of these systems are reduced as the concentration of alkali chloride is increased or as the temperature increased.View full abstractDownload PDF (614K) -
Kazuo Hosokawa, Masuzo Ueda, Imao Tamura1977 Volume 41 Issue 1 Pages 94-101
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA study has been made of the formation of the VC or NbC layer by immersion in a hot bath consisting of Fe-V or Fe-Nb powder, carbonate, Al2O3, KCl and NaCl.
The results obtained are summarized as follows.
(1) The following reactions seem to take place in the bath:
(This article is not displayable. Please see full text pdf.)
\ oindentA part of V or Nb causes the reduction of CO2, and the remainder acts as forming the VC or NbC layer on the steel surface.
(2) Two layers are formed on the steel surface immersed in a hot bath consisting of Fe-V, Al2O3, KCl and NaCl. X-ray diffraction patterns show that the outer layer and the inner layer consist of V2C and VC, respectively. In a bath containing carbonate, only the VC layer is formed.
(3) No carbide layer is formed on the steel surface immersed in a hot bath consisting of Fe-Nb, Al2O3, KCl and NaCl. In the bath containing carbonate, however, the NbC layer is formed. The thickness of the layer increases with increasing carbon content in steel and treating time.
(4) Formation of the V2C and VC layer seems to be due to the reaction between carbon in steel and vanadium in Fe-V powder which is readily dissolved in KCl and NaCl; and the NbC layer is thought to be formed by the reaction between CO and Nb in the bath with the aid of MO (Na2O, K2O, BaO).View full abstractDownload PDF (1122K) -
Yasukiyo Ohtani, Jin-ichi Takamura, Nobutaka Narita, Hiroyasu Yamamoto ...1977 Volume 41 Issue 1 Pages 102-110
Published: 1977
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe significance of primary coplanar slip in work hardening of fcc crystals is emphasized in this paper. In order to differentiate the primary coplanar slip from the primary main slip, observations were made by a scanning electron microscope using the reflective mode and also by a few other methods at the specific specimen surface at which the displacement due to the coplanar slip is opposite to that by the main slip. Precise X-ray measurements also were made for detecting the lattice rotation due to the coplanar slip which should result in the deviation from the ideal rotation due to the main slip. The results obtained by using Cu-Ge alloy crystals are summarized as follows: (1) The operation of primary coplanar slip S13 (see Table 1 and Fig. 1) in the early stage I of the stress-strain curve depends on the crystal orientation. The condition necessary for such operation of the coplanar slip in early stage I is given by eq. (2) or (3). (2) As deformation proceeds from the end of stage I to stage II, the coplanar slip S13 is frequently observed in the vicinity of deformation bands such as kink bands and bands of secondary slip. The main cause for such operation of S13 is to relax the twisting moment arising from ‘bend gliding’ which inhomogeneously develops in stage I. Thus, the operation of S13 contributes to the stabilization of the bend gliding, leading to the formation of deformation bands thereby. (3) In particular, the coplanar slip operating near kink bands plays an important role in the transition from stage I to stage II through the stabilization of bend gliding into kink bands. In other words, the extent of stage I which terminates with the formation of deformation bands is expected to vary with the condition for the operation of the primary coplanar slip.View full abstractDownload PDF (929K)
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