巻号一覧
67 巻, 4 号
選択された号の論文の19件中1～19を表示しています
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村上 雄, 石井 信雄, 長谷川 浩一, 落合 鍾一2003 年 67 巻 4 号 p. 137-140
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーUsing the X-ray pole figure method, hardness test and optical metallography, rolling and recrystallization textures were investigated. After 98% cold reduction, copper type rolling texture developed at the rolling surface. Sharp cube texture with orientational spread around rolling direction was observed after annealing. To intensify the cube texture, the process of partial annealing and light rolling before final annealing is effective in the platinum-rhodium alloy as in the case of aluminum. Orientational spread around the rolling direction was attributed to lattice rotation during rolling in the cube band near to the specimen edge.抄録全体を表示PDF形式でダウンロード (358K) -
水内 潔, 井上 漢龍, 杉岡 正美, 伊丹 正郎, 川原 正和2003 年 67 巻 4 号 p. 141-144
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーA pulsed current hot pressing (PCHP) technique was used to prepare Ti/Ti-aluminides laminate composites. Through this technique, a combustion synthesis reaction was initiated at the interface between Ti and Al foils, resulting in the formation of multi-layered Ti-aluminides between Ti foils and the Ti-aluminides were densified and bonded to the Ti layers. Microstructure of the composite produced was an alternatively-laminated structure composed of Ti and Ti-aluminides. Tensile tests carried out for the composites at room temperature revealed that the mechanical properties of the composites changed by altering the thickness of the Al foils used. The tensile strength and the elongation of the composite produced from 0.04 mm-thick Ti and 0.012 mm-thick Al foils attained to about 700 MPa and 3.5%, respectively. These mechanical properties of the composite produced by PCHP were higher than those by conventional vacuum hot pressing techniques. Microstructural observations of fractured specimens showed that the Ti layers effectively trapped numerous cracks occurred in the Ti-aluminides.抄録全体を表示PDF形式でダウンロード (510K) -
本城 貴充, 矢部 洋正, 礫石 真吾, 内田 晴久, 西 義武2003 年 67 巻 4 号 p. 145-148
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーHydrogen storage alloy, accompanied by a volume expansion of more than 24% by hydrogenation, exhibits enormous high levels of expanding force. An actuator using this phenomena functioning by hydrogen pressure change may exhibit both drastically large fore and shape changes. Hydrogen storage alloy is, however, pulverized by the hydrogenation, therefore, thin film in about 1 μm thick of a hydrogen alloy was used as actuator material, which was not pulverized by the hydrogenation. Compositional dependence of LaNix (x=3.8 to 6.5) on the actuation behavior was investigated in this study. The largest displacement was observed for the test device with the composition of LaNi5, which indicated the largest storage capacity for the hydrogen.抄録全体を表示PDF形式でダウンロード (456K) -
小林 孝幸, 小池 淳一, 吉田 雄, 鎌土 重晴, 鈴木 真由美, 丸山 公一, 小島 陽2003 年 67 巻 4 号 p. 149-152
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーPolycrystalline Alloys of Mg-3Al-1Zn (AZ31) were obtained by equal channel angular extrusion and subsequent annealing at 300°C for 24 h or at 500°C for 4 h. These samples had average grain sizes of 7 μm and 50 μm, respectively. Tensile tests were performed at room temperature at an initial strain rate of 1×10−3 s−1.
The microstructure of the deformed samples at 2% strain was observed by transmission electron microscopy. Active slip systems were determined from the ratio of resolved shear stress (plastic anisotropy factor, PAF) for non-basal/basal slip systems. In the material with large grains (PAF=15.4), non-basal a dislocations were active near grain boundaries, while basal a dislocations were dominant in the grain interior. In the material with fine grains (PAF=0.88), non-basal a dislocations were active in all regions. The density of non-basal a dislocation segments was found to be 40% of the total dislocation density.
The activation of non-basal a dislocations is attributed to induced stresses induced to maintain grain-boundary compatibility. In large grains this effect is limited near the grain boundary. In fine grains, this effect occurs within the entire grain.抄録全体を表示PDF形式でダウンロード (664K) -
甲斐 正彦, 井上 敦士, 星 三郎, 小山 敏, 和泉 輝郎, 村田 清, 塩原 融2003 年 67 巻 4 号 p. 153-156
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーMany applications of superconducting magnets using high-Tc oxide superconductors are expected to operate in the persistent current (PC) mode. For the PC mode operation, the PC switch (PCS) is considered to be an essential device. The special properties are required for the PCS material, which are not only high critical current but high electric resistance in the normal state in order to cut off the current flow efficiently through thermal switching.
We have studied to fabricate meander shaped REBa2Cu3Oy (RE123) LPE films to realize the high electric resistance in the normal state as a persistent current switch material. In the previous study, the meander shaped RE123 LPE films grown from the meander shaped seed films, in which an MgO bare surface exists, reveals low Tc and Jc. The reason for this phenomenon was recognized as that dissolved Mg from the bare MgO substrate was incorporated into the LPE film during growth. A BaZrO3 (BZO), which was confirmed to be stable to the Ba-Cu-O solution even at the high growth temperature, was deposited on the MgO substrate as a buffer layer in order to prevent the MgO dissolution into the solution. In this study, the size controllability of the Y-Yb123 LPE film on the BZO buffer layer was investigated and the control mechanism was discussed. It was found that the size would be controlled by the growth time due to low solutal diffusion flux for surface migration of the growth units on the BZO buffer layer. The size controlled Y-Yb123 LPE film on the BZO buffer layer revealed a high Tc of about 90 K, and the effect of the BZO buffer layer was confirmed from this result.抄録全体を表示PDF形式でダウンロード (415K) -
福山 誠司, 張 林, 文 矛, 横川 清志2003 年 67 巻 4 号 p. 157-160
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーHigh-pressure hydrogen storage system is required for fuel cell vehicle. The effect of hydrogen pressure on the behavior of materials needs to be examined. Tensile properties of type 304 stainless steel were measured using a specially designed pressure vessel up to 39.3 MPa. Ultimate tensile strength, elongation and reduction of area of type 304 stainless steel decreased with increasing the hydrogen pressure up to 39.3 MPa. Crack nucleation and growth are considered. The effect of strain-induced martensite on hydrogen embrittlement is discussed.抄録全体を表示PDF形式でダウンロード (446K) -
福山 誠司, 張 林, 文 矛, 横川 清志2003 年 67 巻 4 号 p. 161-164
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーTensile properties of Fe-Cr alloys of chromium content up to 30% were investigated from 1.1 to 39.3 MPa of hydrogen and in 0.6 MPa of argon at room temperature by using a specially designed equipment. The results obtained are as follows.
1. Annealed Fe-Cr alloys of Cr content up to 30%
Elongation and reduction of area of the annealed alloys decreased with increase in hydrogen pressure, while hydrogen showed no effect on 0.2% proof stress and tensile strength. Hydrogen environment embrittlement (HEE) was minimized at 4∼8% of chromium content, and HEE increased with increase in chromium content above 12%. It is considered that the crack formed by hydrogen on the surface propagated rapidly, when plastic deformation occurred near the maximum load point in stress-strain diagram.
2. Fe-Cr alloys of 16∼30%Cr content aged at 748 K
Hydrogen susceptibility of aged alloys of 16 to 20% chromium content from was larger than that of annealed alloys, and HEE behavior was the same as that of annealed ones. In the aged alloys of 25 to 30% chromium content, the tensile strength, elongation and the reduction of area greatly decreased with increase both in hydrogen pressure and chromium content, while hydrogen showed no effect on 0.2% proof stress. It is considered that the aging at 748 K enhanced the cleavage fracture sensitivity, and a small crack formed by hydrogen with small plastic deformation induced the cleavage fracture easily, thus the aging at 748 K increased the HEE sensitivity.抄録全体を表示PDF形式でダウンロード (466K) -
福田 正2003 年 67 巻 4 号 p. 165-168
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーThe effect of morphology of titanium carbides on the toughness of 30% chromium ferritic steels containing carbon and titanium was investigated by a Charpy impact test at low temperatures. Carbon and titanium contents vary from 0.011 to 0.071 mass% and from 0.094 to 0.60 mass%, respectively. Ti/C ratio is about nine times. Two kinds of heat treatments including with or without solution treatment were adopted to obtain different types of morphology of numerous fine grain boundary titanium carbides under 0.1 μm in diameter and uniformly dispersed coarse globular titanium carbides in the 1 μm size range.
The results obtained are summarized as follows:
(1) Ductile-brittle transition temperatures (DBTTs) increased with increasing titanium carbides independent of the morphology of titanium carbides.
(2) Numerous fine grain boundary Ti carbide precipitates led to an increase in the DBTTs more than uniformly dispersed coarse globular Ti carbide particles.
(3) In case of titanium carbides less than 0.25 vol%, DBTTs estimated for the specimens having grain size of 80 μm are also higher in the specimen with the grain boundary carbides than in the specimen with the uniformly dispersed ones.
(4) Initiation of microcracks for brittle fracture is considered to be caused by the intergranular fracture cracks which are brought about by the decohesion at the interfaces between the matrix and many grain boundary Ti carbide precipitates.抄録全体を表示PDF形式でダウンロード (472K) -
和田 真, 小池 淳一, 丸山 公一2003 年 67 巻 4 号 p. 169-172
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーCu thin films were prepared either by sputtering or by electroplating. The two types of films were investigated for the evolution of microstructure and texture in relation to the progress of room temperature recrystallization using an X-ray diffractmeter and an EBSP apparatus. It was found that room-temperature recrystallization was observed in both types of films. The texture in the as-deposited films strongly affected the occurrence of room-temperature recrystallization. XRD and EBSP results indicated that room-temperature recrystallization was not observed in highly (111)-orientated films, while it was observed in randomly orientated films. Measurement of full width at half maximum of X-ray diffraction peaks indicated that the degree of inhomogeneity in strain distribution was larger in the randomly orientated films than in the highly (111)-orientated films. The inhomogeneous strain distribution in the randomly orientated films decreased with the progress of room temperature recrystallization. These results suggest that room-temperature recrystallization was induced by the presence of large inhomogeneous strain and random texture.抄録全体を表示PDF形式でダウンロード (386K) -
小野 長門, 合谷 仁, 三浦 精2003 年 67 巻 4 号 p. 173-176
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーIt is widely recognized that precipitation hardening brings considerable improvements of mechanical properties in 7000 type Al-Zn-Mg-Cu polycrystalline alloys. In order to make clear the effects of grain boundaries on yielding, we have studied the relationship between flow stress and slipped grain size for 7475 alloys by using an in-situ observation of slip bands. Two kinds of specimens were prepared; one was a solution treated at 753 K for 1.1 ks, and the other one was a solution similarly treated and T6 aged at 393 K for 86.4 ks. The in-situ observations in the surface grains of both specimens were continuously performed in deformation ranges from 0 to about 1% plastic strain. The Hall-Petch relation was confirmed between the flow stress and the average slipped grain size in the vicinity of 0.2% proof stress, although each specimen consisted of heterogeneous grains of different sizes. The slope ky in the relation was almost independent of aging, and the increase of frictional stress σ0 with aging was remarkable. The shear stress for releasing edge dislocation locking derived from the values of ky and σ0 in an as-quenched specimen was twice as great as the CRSS of 7475 alloy single crystals. Comparing the values of σ0 in as-quenched and aged specimens, the increase of frictional stress with T6 aging was in agreement with 270 MPa estimated for 0.5% proof stresses of single crystal alloys.抄録全体を表示PDF形式でダウンロード (294K) -
小林 慶三, 松本 章宏, 西尾 敏幸, 尾崎 公洋2003 年 67 巻 4 号 p. 177-180
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーTi-2 at%Fe-10 at%Si amorphous powder was synthesized by mechanical alloying (MA) of pure Ti, Fe and Si powders using a planetary ball milling for 1440 ks. The crystallization temperature of the obtained amorphous powder was about 830 K.
Ti-2 at%Fe-10 at%Si amorphous powder was consolidated using a pulsed current sintering (PCS) process at a die temperature of 773 K under a pressure of 372 MPa. The compact was densified at the die temperature between 743 K and 763 K with the crystallization of amorphous phase. The obtained Ti-2 at%Fe-10 at%Si alloy consists mainly of nanocrystalline α-Ti phase. The compressive strength of the nanocrystalline compact at a room temperature was more than 1.7 GPa, which was much higher than that of the commercial Ti-6 mass%Al-4 mass%V alloy.抄録全体を表示PDF形式でダウンロード (474K) -
山本 潤一, 清水 保雄, 大谷 草, 塩崎 圭輔2003 年 67 巻 4 号 p. 181-184
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーP-type and n-type β-FeSi2 was produced by utilizing the process of mechanical alloying (MA) and spark plasma sintering (SPS) technique. Raw powders of pure iron, silicon, manganese and cobalt were mixed and mechanically alloyed for 72 ks using planetary ball mill. The mixing fractions of the powders were in accord with the mole fractions of the Fe0.92Mn0.08Si2 (p-type) and Fe0.98Co0.02Si2 (n-type), respectively. The SPS temperature for producing p-type β-FeSi2 was 1073-1153 K and n-type β-FeSi2 was 1073-1173 K, and the holding time was 0.3 ks. When the sintering temperature was over these temperature, α-FeSi2 was produced and thermoelectric properties was reduced. The density of p-type β-FeSi2 sintered at 1153 K was 4.64 g/cm3 (the relative density was 94.1%), and the maximum powerfactor was 0.30 mW/mK2 at 850 K. The density of n-type β-FeSi2 sintered at 1173 K was 4.71 g/cm3 (the relative density was 95.5%), and the maximum powerfactor was 0.058 mW/mK2 at 650 K.抄録全体を表示PDF形式でダウンロード (424K) -
及川 昌志, 南田 勝宏, 出村 雅彦, 岸田 恭輔, 平野 敏幸2003 年 67 巻 4 号 p. 185-188
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーThin foils of stoichiometric Ni3Al with a minimum thickness of 20 μm were successfully fabricated by heavy cold-rolling without intermediate annealing. These thin foils are promising as lightweight, high-temperature structural materials for honeycomb structures, metal substrates of automobile gas exhaust catalytic systems, and component materials of micro channel chemical reactors. Laser-welding can produce welded parts with low heat distortion, and manufacturing honeycomb structures requires many welded parts. Welding with low heat distortion is achieved by rapid heating and rapid cooling, which are advantages of laser welding. However, a solidification crack can still be generated in a welded part. We therefore developed a hybrid laser-welding process that controls the rapid cooling and thereby prevents solidification cracks from forming. This paper reports the welding conditions for producing 90 μm thick lap welds with a hybrid laser spot-welding process that controls the cooling speed of a laser welded part and prevents solidification cracks from forming.抄録全体を表示PDF形式でダウンロード (680K) -
板垣 孟彦, 中里 浩二, 九津見 啓之, 鳥塚 史郎2003 年 67 巻 4 号 p. 189-192
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーThe steam oxidation behavior of Mod. 9Cr-1Mo ferritic steel, which was pre-oxidized in air after heavy compressive deformation, was studied. This procedure provided a Cr2O3-type thin oxide layer, which has oxidation protectiveness in high temperature steam atmosphere. The protectiveness of such oxide layer, however, depended on the magnitude of deformation. The thin protective layer which formed on the severely deformed region maintained during the test period of up to 1.44 Ms in steam at 650°C, while thick oxide scale grew on the region provided with less deformation.抄録全体を表示PDF形式でダウンロード (715K) -
阿部 聡子, 伊藤 孝, 篠田 哲守, 清宮 義博2003 年 67 巻 4 号 p. 193-196
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーThe dependence of the superconducting critical temperature Tc on composition has been investigated for A15-type Nb3Al compounds. The Tc and the composition of the samples have been determined by the specific heat measurement and exactly by the electron probe microanalysis (EPMA) measurements, respectively. The Tc is determined, on the other hand, by the magnetic flux transmission ratio through the sample. The Tc dependence on the Al composition determined by the specific heat measurement is the same as that by the magnetic flux transmission measurement. The determination of Tc by the magnetic flux transmission give the macroscopic Tc of the samples where the composition and its distribution are certified by the EPMA measurements.
The superconducting critical temperature Tc and the lattice parameter are investigated for Nb3(Al, Ge) compounds, whose Ge atoms go into the Al-site, in comparison with those of Nb3Al compounds. The prepared samples Nb1−x(Al, Ge)x have the composition between 0.22≤x≤0.26. The Tc is evaluated by the magnetic flux transmission ratio. The samples are characterized by the powder X-ray diffraction, and the lattice parameter is evaluated quantitatively by the Rietveld method. The Tc of Nb3(Al, Ge) compounds shows above 18.0 K. The Tc=18 K of Nb3(Al, Ge) compounds, which is equal to that of the stoichiometric composition of Nb3Al, is strongly related to the Nb-ordering for the Nb-site. The ordering for the (Al, Ge)-site and the balance of among Nb, Al and Ge atoms in addition to the decrease of the lattice parameter is important to increase the Tc above 18 K. The solute region of A15-type Nb3(Al, Ge) is larger than that of A15-type Nb3Al at the side of the (Al, Ge)-rich composition.抄録全体を表示PDF形式でダウンロード (291K) -
新野邊 幸市, 瀧山 直之2003 年 67 巻 4 号 p. 197-200
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーTo improve the oxidation resistance of a TiAl alloy, diffusion coating using Al3Ti-based powders was developed. In this technique, the coating powder was melted by heating at temperatures above the melting point without using activators such as ammonium chloride. The coating powder of Ti-75 at%Al which consisted of D022-Al3Ti phase and those of Ti-65 at%Al-10at%Cr and Ti-60 at%Al-15 at%Cr which consisted of L12-(Al, Cr)3Ti phase were prepared. The effect of the addition of alumina powder was also investigated. When the alumina powder was not added, all used powder adhered to the substrate and coating layer of more than 1 mm in thickness was obtained, but there were many pores larger than 100 μm. When the alumina powder was added to 20% in weight, the extra powder was readily exfoliated by scratching and the coating layer of about 20∼60 μm in thickness was uniformly formed on the substrate surface. The thickness of the coating layer was significantly affected by the heating temperature and increased by heating at temperature of the vicinity of the melting point.抄録全体を表示PDF形式でダウンロード (825K) -
水谷 明博, 罍 教仁, 小栗 和也, 利根川 昭, 西 義武2003 年 67 巻 4 号 p. 201-204
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーCarbon fiber reinforced plastics (CFRP) have been applied as high-strengthened light structural materials in the fields of aerospace and rapid tranport engineering. In order to enhance bending fracture stress, the electron beam (EB) irradiation was homogeneously performed. EB-irradiation enhanced bending fracture stress and fracture strain of CFRP. EB-irradiation also slightly enhanced bending elasticity of CFRP. Based on mixture law, we concluded that EB strengthening of CFRP was mainly dominated by ductility enhancement of epoxy resin and elasticity of carbon fiber.抄録全体を表示PDF形式でダウンロード (429K) -
小泉 裕, 小林 敏治, 横川 忠晴, 大沢 真人, 原田 広史, 日野 武久, 吉岡 洋明2003 年 67 巻 4 号 p. 205-208
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーThe γ′ fraction dependence of the creep properties of the second generation single crystal (SC) Ni-base superalloy, TMS-82+, and their γ⁄γ′ tie-line alloys is presented. The γ′ fraction is varied between 0 and 100%. The γ and γ′ phases of the alloys are designed to have the same chemical composition so that γ′ fraction dependence can be assessed independently. The γ single-phase alloy is weaker than the γ′ single-phase alloy. The best creep property is obtained with the γ′ fraction between 60 and 70%, depending on the creep condition. The optimum γ′ fraction decreases at higher temperature and lower stress. The SC alloys show larger γ′ fraction dependence compared with the conventionally cast polycrystalline alloys previously reported.抄録全体を表示PDF形式でダウンロード (686K) -
伊原 健太郎, 美浦 康宏2003 年 67 巻 4 号 p. 209-217
発行日: 2003年
公開日: 2008/04/24
ジャーナル フリーThe main purpose of this study was to clarify the process of dynamic recrystallization (DRX) of pure Al single crystals by using the synchrotron radiation (SR) Laue technique and the electron backscatter pattern (EBSP) technique. Compression tests were made at 473 K with an initial strain rate of 10−3 s−1 using a test machine designed to fit on the camera stage of Synchrotron Radiation apparatus at SPring 8-BL28B2. The ⟨111⟩ crystallographic orientation was chosen as the compression axis. During a compression test, transmission Laue spots were recorded. As plastic deformation of the crystal proceeded, the Laue spots of the matrix streaked toward the center of the film. Before the first stress peak, the streaks of the Laue spots reached a plateau. Just before the peak stress was reached, the brightness of the new spots from the DRX grain increased at the end parts of the streaks of the original Laue spots. After the stress peak, the Laue spots from the DRX grain suddenly brightened and streaked as those from the matrix disappeared. The crystallographic orientation relationship between the DRX grain and the matrix was mostly explained by analyzing the slip systems in the matrix. The misorientation of DRX grain boundaries might be slightly larger than that of the surrounding subgrain boundaries when DRX occurs. These observations imply that DRX is the process that a field which has a higher angle boundary than surrounding subgrain in the matrix grows during deformation.抄録全体を表示PDF形式でダウンロード (1345K)
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