巻号一覧
60 巻, 3 号
選択された号の論文の16件中1～16を表示しています
- |<
- <
- 1
- >
- >|
-
大石 敬一郎, 田 文懐, 佐野 毅, 根本 実1996 年 60 巻 3 号 p. 239-246
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーMicrostructural variations and correlated hardness changes in a pseudobinary NiAl(B2)-Ni2AlTi(L21)-NiTi(B2) system have been investigated by means of transmission electron microscopy (TEM) and hardness tests. The hardness after solution treatment is high in NiAl- and NiTi-base alloys suggesting the large contribution of solid solution strengthening in this alloy system. However, the amount of age hardening is not large as compared to the large microstructural variations during aging. TEM observations have revealed that spinodal and binodal types of decomposition occur depending on the chemical compositions and aging temperatures. At the beginning of aging, the L21-type Ni2AlTi precipitates keep a lattice coherency with the NiAl and NiTi matrices. By longer periods of aging Ni2AlTi precipitates lose their coherency and change their morphology to the globular ones surrounded by misfit dislocations. Misfit dislocations, which are observed on {100} planes of H-precipitates have the Burgers vector of a ⟨100⟩ with a pure edge type. The lattice misfits of NiAl-Ni2AlTi and NiTi-Ni2AlTi systems are estimated from the spacings of misfit dislocations to be 1.1% and 1.3% respectively at 1273 K. The lattice misfits decrease with increasing aging temperature in both the systems. The results of the present observations are compared with the previously reported phase diagrams.抄録全体を表示PDF形式でダウンロード (2622K) -
山本 悟, 坂口 忠晴, 宇田 哲也1996 年 60 巻 3 号 p. 247-253
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーIn the present work, the range of chemical composition and the condition of working and heat treatment for work-softening in Zn-Al alloys were examined. Work-hardening in Al-rich alloys and work-softening in Zn-rich alloys were always observed regardless of pre-treatment conditions. Recovery and recrystallization in the work-softened specimens was confirmed by the measurements of micro-Vickers hardness and the observations of optical microstructure. It has been suggested that the cold-working causes the precipitation of dissolved Al which results in the lowering of recrystallization temperature and that the work-softening occurs due to the recovery and recrystallization of worked-specimens at room temperature. In Al-rich alloys, the work-softening was suppressed. This was because the precipitation of Zn was relatively suppressed and remained in the state of the formation of G.P. zones and then the recovery and recrystallization did not proceed.抄録全体を表示PDF形式でダウンロード (714K) -
山本 悟, 宇田 哲也, 今堀 旬司1996 年 60 巻 3 号 p. 254-260
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーIn Zn-Al alloys, work-hardening in Al-rich alloys and work-softening in Zn-rich alloys were observed respectively. The micro-Vickers hardness of work-softened specimens was increased and, on the contrary, that of work-hardened-specimens was decreased by solution treatments. The electrical resistivity was increased by solution treatments in both work-softened and work-hardened specimens. The structures of cold-rolled textures and those in the midst of recovery and recrystallization were observed in the work-hardened and work-softened specimens, respectively. In the work-softened alloys, the lattice parameters of the Al-rich phase were determined by X-ray diffraction to be in approximate agreement with that of pure Al, and those of the Zn-rich phase, in agreement with that of pure Zn. Age-hardening was observed and the electrical resistivity increased in the work-hardening Al-rich alloys when aged at room temperature after solution treatments. On the other hand, age-softening was observed and the electrical resistivity decreased in the work-softening Zn-rich alloys. These experimental results provided the evidence for the precipitation, recovery and recrystallization during working. Based upon these discussions, the mechanism of work-softening in Zn-Al alloys is as follows: Cold-working causes the precipitation of dissolved Al, which results in the lowering of recrystallization temperature and the work-softening occurs due to the recovery and recrystallization at room temperature.抄録全体を表示PDF形式でダウンロード (1106K) -
佐野 直幸, 前原 泰裕1996 年 60 巻 3 号 p. 261-268
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーCopper precipitation at early stages in Cu-added ultra-low carbon steel has been investigated by differential scanning calorimetry (DSC), high-resolution transmission electron microscopy (HRTEM) and atom-probe field-ion microscopy (APFIM). Two exothermic reactions are observed around 638 and 838 K by DSC, of which the activation energies are determined to be 53.1 and 230.2 kJ/mol respectively. The second exothermic reaction is thought to be the formation of ε-Cu precipitates and governed by the volume diffusion of Cu in α-Fe matrix. At the first exothermic reaction the formation of Cu clusters consisting of about 10 atoms occurs. The activation energy of the first exothermic reaction and the size of the Cu cluster agree with those of the critical nucleus estimated from the classical nucleation theory. The onset temperature of the first exothermic reaction shifts to a lower temperature by pre-strains, suggesting the important role of defects, such as vacancies and dislocations.抄録全体を表示PDF形式でダウンロード (1290K) -
加藤 鋭次, 加藤 一幸, 野村 宏之1996 年 60 巻 3 号 p. 269-275
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーMicrostructure of cast aluminum alloys based on Al-7%Si-1%Fe has been investigated adding Cr and Be with the low-frequency-vibration treatment.
The size of iron compounds are controlled by the vibration treatment, applied during the solidification. The length of needle-like and Chinese script iron compound decreases with increasing vibrational energy. As the result, the decreased size of iron compounds yields the improved toughness of the alloy. Besides, it is found that the proeutectic iron compounds are formed to be wholly massive with the low frequency of 15 Hz. Massive iron compounds become small in size with increasing vibrational energy.抄録全体を表示PDF形式でダウンロード (1385K) -
中山 栄浩, 鷹合 徹也1996 年 60 巻 3 号 p. 276-281
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーEffects of one-pass rolling on the surface residual stresses generated in the 5083 aluminum alloy plates were investigated. Generation behavior of the residual stresses was examined in terms of plate thickness, reduction per pass and working roll diameter. Measurement of the surface residual stresses in the rolling direction was made by an X-ray analysis method. Distributions of the surface residual stresses in the plate contact area of the working rolls were also measured. Generation mechanisms of the surface residual stresses were discussed. The major results are summarized as follows: Tensile residual stresses for various initial thickness specimens initially increase with increasing in plate thickness and then show peak values at a specific plate thickness. The specimens rolled by small working rolls show higher tensile residual stresses than the specimens rolled by large working rolls. Inhomogeneities of the plastic deformation in a range of X-ray penetration depths have a great influence on the generation of surface residual stresses.抄録全体を表示PDF形式でダウンロード (870K) -
前 健彦, 井原 正夫, 小村 一成, 鳥山 成一, 砂田 聡, 新井 甲一1996 年 60 巻 3 号 p. 282-289
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーThe effects of Ga content and aging treatment on stress corrosion cracking characteristics of Al-9 mass%Mg-X mass%Ga alloys are investigated by the measurements of number of precipitates and their occupation ratios to grain boundary, transmission electron diffraction analysis of precipitates, mechanical properties, time to failure of stress corrosion cracking and scanning electron micrographs of stress corrosion cracking fracture surfaces for the specimens aged at 453 K in a mixed solution of 3×10−2 kmol/m3 K2Cr2O7+1×10−2 kmol/m3 HCl+5×10−1 kmol/m3 NaCl at 303 K under a loaded stress of 0.9×0.2% proof stress.
The main results obtained are summarized as follows:
(1) The number of Al3Mg2 precipitates and its occupation ratios to grain boundary of Al-9 mass%Mg-X mass%Ga alloys aged at 453 K increase with increasing aging time. When the aging time is longer than 40.0 ks, the precipitates are observed in the transcrystalline, and the precipitate free zone is formed around the grain boundary layer irrespective of stoichiometries of the specimens. The Mg2Ga or MgGa2 compound is detected in the precipitates of Ga containing specimens.
(2) The effects of Ga content and aging treatment on mechanical properties such as U.T.S. and 0.2% proof stress of Al-9 mass%Mg-X mass%Ga alloys are rather small.
(3) The time to failure of stress corrosion cracking of the specimens is reduced with increasing aging time irrespective stoichiometries of the specimens used. However, the time to failure of stress corrosion cracking increases with increasing precipitates in the transcrystalline of the specimens. The failures from stress corrosion cracking of the specimens are primarily intercrystalline.抄録全体を表示PDF形式でダウンロード (1583K) -
竹下 博之, 香川 卓也, 鈴木 亮輔, 大石 敏雄, 小野 勝敏1996 年 60 巻 3 号 p. 290-294
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーQuantitative analysis of trace amounts of dominant impurities in copper, Ag, Fe, Ni and Pb, were studied using secondary ion mass spectrometry (SIMS). Based on the survey of the secondary ions species, which disturbed the detection of atomic ions of impurities, the removal of these disturbance is proposed as the two methods; applying the high resolution of mass spectrometry, and calculating the isotopic abundance. The precision, detection limit and relative sensitivity factor were experimentally discussed to establish the reliable quantitative SIMS analysis at the local area of high purity copper.抄録全体を表示PDF形式でダウンロード (575K) -
木村 秀夫, 沼澤 健則, 佐藤 充典1996 年 60 巻 3 号 p. 295-300
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーPhase-formation process in solid-state synthesis of Dy3Al5O12 has been investigated at the heating and isothermal processes using Dy2O3 and Al2O3 powders. Phase formation was determined by powder X-ray diffraction using Si powder as a standard. The Dy-Al oxide system has three compounds consisting of garnet, perovskite and monoclinic. In the case of using any starting powders of the three compound compositions, the perovskite phase was most easy to form. The garnet single phase was difficult to form at the heating process up to 1700°C even using garnet composition powders. The difficulty to form the garnet phase was also studied in a phase formation of the R3Al5O12-R3Ga5O12 (R: Dy, Y and Gd) solid solution using garnet-composition powders on the basis of ionic radii of rare-earth elements.抄録全体を表示PDF形式でダウンロード (627K) -
松木 一弘, 畑山 東明, 柳沢 平1996 年 60 巻 3 号 p. 301-310
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリー1.8∼7.8 mol%MoS2 is added to WC-20 mol%Co of a basic alloy system to develop cemented carbides having the ability of self-lubrication, where MoS2 is well known as one of the solid lubricants. The spark sintering has been applied to the sintering of these MoS2 containing carbides. The evaluation of microstructures, the hardness and charpy impact tests are also carried out on the spark sintered compacts. The results obtained from this study are summarized as follows. The conditions selected as the optimum sintering condition for WC-20Co. are: The number of pulse is 3000 for preliminary treatment of powders, and the resistance sintering temperature and time are 1473 K and 0.6 ks, respectively, where the decreasing rate of specific resistivity of compacts is a guide to the determination of the number of pulse, and the microstructure, displacement of densification and hardness are guides to the determination of the resistance sintering conditions. These conditions are also used in the spark sintering process of MoS2 containing carbides. Only three materials, WC, Co and MoS2, are identified in the compacts which are sintered under the conditions mentioned above. It is considered that the exposed period of compacts are short (0.6 ks) at the maximum sintering temperature (1473 K) and single or condensed particles of MoS2 are surrounded by WC-Co compacts whose relative densities are more than 70% at the thermal decomposition temperature (approximately 1273 K), which lead to the residue of MoS2 in the sintered compacts. On the other hand, the hardness and Charpy impact values have a tendency of decreasing with the MoS2 content in carbides. In particular, the rate of decrease of these values are larger for the compacts low in the content of MoS2.抄録全体を表示PDF形式でダウンロード (2807K) -
趙 源丞, 宮崎 武彦, 土井 良彦, 林 宏爾1996 年 60 巻 3 号 p. 311-317
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーThe miniaturization of a thermoelectric generator of gas combustion type requires a sharp temperature gradient between hot and cold junctions. It has been proposed by R. Echigo that this could be achieved by flowing a mixture of inflammable gas and air through the continuous coarse pores of a porous thermoelectric transducer and burning it at the outlet. The present article describes the preparation and thermoelectric properties of chromel/alumel porous sintered compact for the thermoelectric transducer. The average particle sizes of both chromel and alumel coarse powders were about 300 μm.
Under the conditions of the relative density of green compact of 70%, sintering atmosphere of vacuum (10−3 Pa), sintering temperature of 1623 K and sintering time of 3.6∼14.4 ks, porous chromel and alumel sintered compacts having the following properties were obtained; continuous pores (porosity, 30%; relative density, 70%), appropriate mechanical property (bending strength at room temperature, above 90 MPa), specific electrical conductivity of about 2.5∼3.6×105 S·m−1 (ratios to the value of dense compact are about 17∼24%) and 10∼15×105 S·m−1 (23∼35%), respectively, and thermal conductivity of 7.1∼10 Wm−1 K−1 (23∼32%) and 13∼16 Wm−1 K−1 (32∼39%). And the porous thermoelectric transducer, i.e., joint of the two kinds of the sintered compacts having thermoelectric power of 4.2∼4.3×10−2 mV·K−1 (100%) and figure of merit of 2.2∼2.6×10−5 K−1 (76∼90%) were obtained under the same conditions.抄録全体を表示PDF形式でダウンロード (2185K) -
大野 悟, 奥山 秀男, 本間 一廣, 目 義雄1996 年 60 巻 3 号 p. 318-323
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーThe ignition phenomenon of ultrafine metal particles of Fe, Ni and Co (metal UFP) in oxygen atmosphere has been investigated by using differential thermal analysis. The ignition points of those metal UFP increases gradually with decreasing of the heating rate, but no ignition (slow oxidation) is observed under the heating rate lower than a certain critical value.
It is considered that the ignition of metal UFP at the heating process is caused by fast oxidation of a fresh metal surface exposed to atmosphere because the oxide layer on a particle is broken by thermal stress induced under a quick heating process.抄録全体を表示PDF形式でダウンロード (561K) -
大橋 修, 目黒 奨1996 年 60 巻 3 号 p. 324-330
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーIon bombardment is known to be effective in removing all surface contaminants and oxides. Bonding is often carried out after the bonding surface is cleaned using ion bombardment. However, it is not clear what changes occur at the surface. This investigation has been carried out to determine what changes occur at the surface of a metal and improve the quality of joint. Joints were made using samples estimated by Auger spectroscopy in an ultra-high vacuum joining equipment. To observe changes at the surface, surface composition, surface morphology, hardness and fracture surface were investigated. Results obtained are summarized as follows;
1. Joints could not be made at room temperature but at 300°C using copper samples treated by argon ion bombardment. The joint strength depended on the accelerating voltage at ion bombardment. It was best to bond the samples treated at accelerating voltage of 2 kV. The joint strength decreased with a rise of accelerating voltage above 2 kV.
2. When ion bombardment was carried out at accelerating voltage up to 2 kV, the increase of joint strength depended on the rise of purity of the bonding surface.
3. Argon ion bombardment at the accelerating voltages from 2 up to 5 kV formed a hard surface layer. This layer was removed by the annealing treatment of samples after argon ion bombardment. With softening of the bonding surface, the joint strength increased. A reason for the decrease of bondability was the formation of the hard surface layer.
4. Surface roughness increased with accelerating voltage. The decrease in joint strength was not attributed to the change of surface roughness, as the change of the bonding area was little.
5. The annealing treatment of the samples after ion bombardment was effective to remove the surface damage.抄録全体を表示PDF形式でダウンロード (771K) -
大橋 修, Khant Tahir lrfan1996 年 60 巻 3 号 p. 331-337
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーIon bombardment is known to be effective in removing all surface contaminations and oxides and improving the quality of diffusion bonds. However, recent work has shown that the accelerating voltage used during the ion bombardment significantly affected the bond strengths. This work has been carried out to investigate the behavior of argon at the surface and bonded interface of copper which are treated by the argon ion bombardment. To observe changes at the surface and the bonded interface, surface composition, surface morphology, gas analysis in voids at interface were investigated, using Auger spectroscopy, reflection high electron diffraction (RHEED), and mass spectrometer technique. Results obtained are summarized as follows:
1. On argon ion bombardment, argon penetrates the surface of copper, and the amount of argon planted increases with accelerating voltage during ion bombardment. When the copper surface is heat-treated, argon is released from the specimens, and the concentration of argon at the surface layer decreases.
2. Argon ion bombardment deteriorates surface flatness and crystal perfection. The extent of these damages increases with a rise of the accelerating voltage.
3. Argon comes out from the voids at bond line of joints which are made using specimens treated by the argon ion bombardment. The presence of argon in the voids is one reason for the deterioration of the joint in the samples bombarded at a high accelerating voltage.
4. The annealing of the samples after the ion bombardment makes the bonding surface clean, removes any surface damage and gives joints free from voids at the bond line.
5. The annealing treatment is effective in removing the surface damage introduced by the argon ion bombardment.抄録全体を表示PDF形式でダウンロード (1004K) -
磯貝 宏道, 秋山 友宏, 八木 順一郎1996 年 60 巻 3 号 p. 338-344
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーCombustion synthesis of Mg2Ni/Mg2NiH4, a typical hydrogen storage alloy, has not been reported in the literature. In this paper, the possibility of combustion synthesis of Mg2Ni/Mg2NiH4 is experimentally studied, in which the influence of particle size, mixing method, compacting pressure and pressurized hydrogen atmosphere on the ignition of Mg-Ni(-H) compact was mainly examined. One end of six kinds of cylindrical compacts was ignited and then the obtained meterials were identified by X-ray diffraction analysis. For obtaining information of reaction mechanism, these samples were also analyzed by high-pressure thermogravimetry, differential thermal analysis, and high-temperature microscope. As a result, combustion synthesis of Mg2Ni was observed and the ignition temperature of the Mg-Ni compact was seen to be close to the eutectic temperature of the Mg-Ni system. The highest purity of Mg2Ni was obtained from the compact prepared with very fine nickel powder (2-3 micron), wet mixing and high loading pressure of 1 GPa. Most significantly, Mg2NiH4 was directly synthesized by heating the compact of magnesium and nickel under a hydrogen pressure as low as 2.0 MPa, although commercially-available pure Mg2Ni did not absorb hydrogen at all. These results arise the possibility of a new production process of hydrogen storage alloy without an activation treatment.抄録全体を表示PDF形式でダウンロード (862K) -
兼子 佳久, 橋本 敏1996 年 60 巻 3 号 p. 345-346
発行日: 1996年
公開日: 2008/04/04
ジャーナル フリーPDF形式でダウンロード (295K)
- |<
- <
- 1
- >
- >|