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Volume 53, Issue 12
Displaying 1-14 of 14 articles from this issue
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Hidehiro Yasuda, Hiroshi Fujita1989 Volume 53 Issue 12 Pages 1191-1197
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTransition metal dichalcogenide TaSe2 with layered structures, in which Ta atomic planes are sandwiched by Se atomic plances, has two-dimensional properties, and causes Peierls trasformation attributed to the periodic lattice distortion at low temperatures. In this study, the relationship between the electron states of solute atoms and lattice distortions in solid solutions are discussed on the basis of two-dimensional metallic TaSe2 at room temperature. Ta atoms in TaSe2 are substituted by Ti atoms and the lattice distortions occur to disorder the potential in Ta metallic planes. The correlation between the electron states localized at Ti atoms and lattice distortions caused by the electron localization are studied. The specimens are (Ta1−xTix)Se2 (x=0, 0.2, 0.4, 0.8). Both transmission electron microscopy and Auger electron spectroscopy were used to investigate the atomic and electronic structures. In the case of Ti content x≤0.2, lattice distortions take place. From the viewpoint of the electronic structures of solute Ti, there are the evidences of the untransferable charge between Ta and Ti atoms and the similarity in valence state between solute Ti and elemental Ti. The periodic potential fluctuates, since solute Ti in Ta planes is characteristic of metallic Ti itself. The conduction electrons are localized under such a potential due to the effects of the two-dimensional structure. Consequently, the lattice distortions are attributable to the electron-lattice interaction. In the case of x>0.2, lattice distortions are inhibited, because the electron remarkably transfers from the Ti to the Ta atom and atomic arrangements are ordered by alloying effects.View full abstractDownload PDF (1572K) -
Shu-Fan Chen, Hiroyuki Komeda, Koji Fujii, Koji Tanoue, Hidehiko Matsu ...1989 Volume 53 Issue 12 Pages 1198-1207
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe time law of primary grain growth and the effect of doping agent, annealing temperature and heating rate on the shape of secondary recrystallized grains and the orientation distribution of the wire axis for them are investigated using sintered tungsten wires. The rate of primary grain growth is obtained from an increase in mean thickness of fibers, showing that the rate is fairly smaller in the doped wire than in the non-doped wire. Doping has another effect on retarding the start of secondary recrystallization from the surface and also its completion at the central part of the wire. The grains of the doped wire are much more elongated in a longitudinal direction than those of the non-doped wire after a complete secondary recrystallization. However, there is the tendency that the grains of both materials become more equiaxed in shape and are distributed near ⟨011⟩ in the wire axis as the annealing temperature and the rate of heating increase. It is concluded that the appearance of large elongated secondary recrystallized grains with a wire axis near ⟨011⟩-⟨135⟩ is directly due to the bubble effect and the large driving force of grain growth inherent in their orientations.View full abstractDownload PDF (2309K) -
Toshiro Tomida1989 Volume 53 Issue 12 Pages 1208-1213
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe stacking structure of close-packed planes within the martensite from δ-ferrite in a melt-quenched δ⁄γ duplex stainless steel ribbon has been investigated by means of high resolution transmission electron microscopy. The observed structure images show that the martensite consists of stackings of close-packed planes with shuffling and lots of stacking faults. The existence probability of the extended shuffling including stacking faults is about 0.35, and more than 80% of the extended shuffling occurs as the two-layer shuffling expressed as ABC-B-ABC. Although the arrangement of the two-layer shuffling was rather in disorder, there exist the areas with the (3\={2})3, (4\={2})3 or (5\={2})1, type stackings of close-packed planes in the Zhdanov’s notation. The existence probability of the (4\={2})3 type stackings is the largest, being 0.27 to 0.43. This martensitic transformation is considered to be that from the δ-ferrite to the (4\={2})3 type long period stacking structure which contains stacking faults with a probability of about 0.16 as the lattice invariant strain.View full abstractDownload PDF (1347K) -
Kyoko Tamai, Jun-ichi Echigoya, Hajime Suto1989 Volume 53 Issue 12 Pages 1214-1221
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe growth and structure of diamond films deposited on (111) Si substrates by the hot-filament CVD method were investigated by use of transmission electron microscopy. The density and growth rate of diamond particles on scratched (111) Si substrates were extremely high compared with that without any scratching of substrates. Fine β-SiC particles were observed over the whole area of the substrate after deposition in any case of surface condition. The nucleation and growth of diamond particles seem to be independent from the existence of SiC particles on substrates.View full abstractDownload PDF (3964K) -
Ryuta Onodera, Keiichi Yasunaga, Beong Young Lee, Hidenori Era1989 Volume 53 Issue 12 Pages 1222-1228
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt has been experimentally clarified that the shear fracture in tension tests of Al-4%Cu-0.5%Mn-0.5%Mg alloy arises from two different origins: the one is the negative strain rate sensitivity of flow stress and the other is the formation of sharp ⟨111⟩ fiber texture. The shear fracture due to the former is observed in the solution treated specimen stretched at ambient temperature, but that due to the latter occurs in the aged specimen stretched not only at ambient temperature but at 77 K. In the aged specimen having nearly random texture the shear fracture does not occur. The texture-induced shear fracture has been analyzed based on the Bishop-Hill theory. The analysis shows that the difference between the stress necessary for the shear deformation and that for the axisymmetrical deformation is less in the specimen with the sharp ⟨111⟩ texture than in that with the random one. Furthermore the geometric softening due to the crystal rotation occurs in the shear deformation zone of the ⟨111⟩ textured specimen. These results can explain that the formation of sharp ⟨111⟩ texture is a requisite for the occurrence of shear fracture in the aged specimen.View full abstractDownload PDF (802K) -
Yasuhiko Hashimoto, Koichiro Koyama, Kenji Suzuki, Atsushi Nanyoshi1989 Volume 53 Issue 12 Pages 1229-1235
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe themodynamic properties of TiCxOy in equiliblium with carbon were determined by measuring the CO pressures in equilibrium with TiCxOy specimens in the temperature range from 1573 K to 2200 K. The results obtained are as follows:
(1) The standard Gibbs energy of formation of TiCxOy can be expressed by the following equations:
(This article is not displayable. Please see full text pdf.)
\ oindent(2) The standard Gibbs energy change for the reaction (1/2)O2(pO2=1 atm)→O(Henrian standard state xO=1) is:
(This article is not displayable. Please see full text pdf.)
\ oindent(3) The Henrian activity coefficient of O in TiCxOy hardly changes with temperature and can be written as
(This article is not displayable. Please see full text pdf.)View full abstractDownload PDF (677K) -
Keisuke Eguchi, In Yong Ko, Tatsuo Sugawara, Hyung Jik Lee, Toyonobu Y ...1989 Volume 53 Issue 12 Pages 1236-1241
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe purpose of this research is to control the condensation process of SiC powder from SiCl4 and CH4 in a “hybrid plasma” which is characterized by the superposition of DC arc jet and RF plasma. In the previous paper, we have already reported the “reactive quanching method” may control the composition and particle size of products. In order to study more quantitatively, we have developed a new designed ring-slit, which could make it possible to change its slit width (Ws) accurately from 400 to 30 μm. By using it, we firstly investigated the decomposition and condensation processes of CH4 by changing the total flow rate (Qs) and linear velocity (Vs) of quenching gas. Based on the result, we synthesized SiC powder from SiCl4 and CH4 and investigated the condensation process of SiC. These experimental results revealed that the decomposition and condensation of CH4 and the condensation process of SiC was affected by Vs and Qs. Especially, it was found that the composition of SiC, and the particle size were affected by both of Vs and Qs, and only Qs, respectively. In other words, the decomposition and condensation of CH4 was considered to be a key factor to control the composition of SiC powder. Further more, the new designed ring-slit system made it possible to control not only the composition of SiC powders but also particle size, and is considered to be an effective device for independent control of gas phase reaction and condensation processes in various chemical systems.View full abstractDownload PDF (1886K) -
Katsutoshi Ono, Takashi Sawai1989 Volume 53 Issue 12 Pages 1242-1247
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAttempts to cement the (Ti W) (C N) carbonitride with binder-metals to form hard alloys have been successful and promising as cutting tool applications. The (Ti W) (C N) solid solutions have ordinarily been prepared by mixing nitrides and carbides intimately and heating them together under vacuum until homogeneity is obtained.
Because of non-affinity between W and N, this solid solution tends to be decomposed at high temperatures. Thus during the sintering procedure of these carbonitrides, nitrogen pressure has to be adjusted within a certain limit to the composition of the carbonitrides.
This study has investigated the processes to prepare directly the (Ti W) (C N) solid solutions by carbothermic reduction of mixed constituent metal oxides at 2273 K and subsequent annealing under fixed nitrogen pressure at 1773 K, and has succeeded in synthesizing homogeneous and stoichiometry-controlled (Ti W) (C N) carbonitrides.
The evaluation of the stability of the carbonitrides against nitrogen has been carried out by measuring the ralationship between nitrogen pressure and composition of the carbonitrides doped with Hf, Zr, Ta, Nb and Mo as the third metallic constituent, and it was found that the carbonitride can effectively be stabilized by adding these elements in this order.View full abstractDownload PDF (767K) -
Eiji Tsuzi, Tomoyuki Mizukoshi1989 Volume 53 Issue 12 Pages 1248-1254
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of Pt on the isothermal oxidation of Fe-24Cr alloys, Fe-24Cr alloys containing 0.063 and 0.87 mass% Y, and Fe-24Cr-4Al alloys containing 0.07 and 0.5 mass% Y at high temperature have been examined. Each alloy, after being coated with a Pt thin film by the spattering method, was oxidized in flowing O2 gas in the temperature range from 1173 to 1523 K. Pt-coating on the Y-free Fe-24Cr aIloy resulted in a marked suppression in oxidation rate, while a significant enhancement in oxidation rate by Pt-coating was observed in the Y-containing Fe-24Cr alloys. Pt-coating had no influence on the isothermal oxidation of the Y-containing Fe-24Cr-4Al alloys. The effects of Pt on the oxidation behavior of Fe-24Cr alloys and the Y-containing Fe-24Cr alloys were discussed in relation to defect structures of Cr2O3 scales formed on the alloys. Marker studies using a thin Pt-wire were performed on the Y-containing Fe-24Cr alloys at 1423 K and on the Y-containing Fe-24Cr-4Al alloys at 1523 K. It was observed that Pt reacted aggressively with Cr2O3 scales and affected the development of them, while Pt on the α-Al2O3 scales was inert.View full abstractDownload PDF (1376K) -
Nobuo Kobayashi, Yoshio Yamasaki, Naotugu Inakazu1989 Volume 53 Issue 12 Pages 1255-1262
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe behavior of corrosion rate in 7.5% HCI aqueous solution of commertial grade zinc sheet rolled up to 90% total reduction under the condition of 3, 5 and 10% reduction per pass, has been investigated by measuring the residual stress and rolling texture by means of X-ray diffraction. In the case of the as-rolled sheet, the corrosion rate indicated a maximum value at 30% total reduction and subsequently a constant value at heavy reductions. In the case of the sheet held for one month at room temperature after cold rolling, the corrosion rate becomes an averaged value for the total reduction and is approximately equal to that of the as-rolled sheet over 40% reduction. The difference of one-pass reduction did not found have any effect on the corrosion rate. The correlation between residual stress and corrosion rate was found. At 30% total reduction, the maximum residual stress generated by twin formation and lattice distortion. Subsequently, the residual stress was released by slip rotation on the basal plane during the rolling over 30% reduction. At heavy reductions, the slip rotation on the basal plane and the twin formation are repeated, and consequently the residual stress shows an approximately constant value.View full abstractDownload PDF (1865K) -
Moritaka Hida, Akira Sakakibara, Hideto Kamiyabu1989 Volume 53 Issue 12 Pages 1263-1267
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSurface tensions (γL) and contact angles (θ) of liquid gallium on Teflon and other substrates (Al2O3, SiO2, glass, graphite, BN, Al, Ni, As etc.) were investigated. The values on Teflon were 0.700 N/m and 156°, respectively, in pure argon atmosphere. we were especially interested in the relative values, γL′s, on the substrates as compared with γL on the Teflon substrate. Liquid Ga showed spreading wetting on pure Ni metal and adhesional wetting on Al (supposed to be corvered by Al2O3), semimetal As and nonmetal substrates. Surface tension of Ga was remarkably decreased by surface oxidation due to oxygen in air. The surface layer of liquid Ga caused by the contamination was in the pasty state where the structure was nearly the same as liquid Ga. The contamination caused liquid Ga a rather high supercooling of ΔT∼35 K. It seems that the origin of this high supercooling was due to the removal of nucleation sites of crystal Ga by the surface oxidation of liquid Ga.View full abstractDownload PDF (697K) -
Akira Chiba, Kazuyuki Hokamoto, Minoru Nishida1989 Volume 53 Issue 12 Pages 1268-1275
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMultilayered aluminum and titanium base composites reinforced with 18%Ni maraging steel sheets were fabricated by the single-shot explosive welding technique. Microstructures and tensile strength of these composites were examined. The effect of heat treatment on the tensile strength of the composites is analyzed based on the rule of mixtures. When the reinforcement exhibits the maximum strength by aging, the ultimate tensile strength of both composites aged after welding is about 1.5 times higher than that of the aged one before welding. The former is slightly higher than that predicted from the rule of mixtures. This increment is attributable to the strengthening by the thin intermetallic compound layer formed by aging. The effect of the thickness of the intermetallic compound layer on the tensile strength of the titanium base composite is also described.View full abstractDownload PDF (2498K) -
Hisakimi Notoya, Shigeru Yonetani, Shigeru Yamada, Yuzo Takatsuji1989 Volume 53 Issue 12 Pages 1276-1281
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of machining conditions on the grindability of austenite stainless steel were investigated by measuring the grinding forces, wheel wear and the effective cutting edge spaces under various grinding conditions.
The grinding forces for austenite stainless steel increased rapidly at the initial stage of grinding process, it is observed that many chips of work material adhered to the peripheral surface of wheel and many abrasive grains failed off actively from the wheel surface.
It is found that the effective improvement of grindavility for austenite stainless steel was obtained by using of high gradewheel and grinding fluid.View full abstractDownload PDF (678K) -
Keiichi Edagawa, Atsushi Waseda, Hiromitsu Ino1989 Volume 53 Issue 12 Pages 1282-1283
Published: 1989
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (277K)
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