巻号一覧
70 巻, 11 号
選択された号の論文の15件中1～15を表示しています
- |<
- <
- 1
- >
- >|
-
佐々木 元, 仲井 清眞, 金谷 輝人, 岡崎 健2006 年 70 巻 11 号 p. 857
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーPDF形式でダウンロード (197K) -
瀬沼 武秀, 竹下 哲郎2006 年 70 巻 11 号 p. 858-864
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーIn this paper, recent research and development of modern steel sheets for automobiles has been reviewed. Therefore, the steel sheets introduced here are not only types in commercial production but also those until now only reported in technical papers.
Besides steel sheets themselves, some technologies contributing to promoting the use of the steel sheet have been introduced, namely hot stamping technology for producing super high-strength parts, and a computer program system consisting of models for predicting microstructure and mechanical properties of steel sheets, a key technology in the future for realizing a modern supply chain management for automotive steel sheets.
抄録全体を表示PDF形式でダウンロード (781K) -
礒部 繁人, 市川 貴之, 藤井 博信2006 年 70 巻 11 号 p. 865-869
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーWe have investigated hydrogen storage materials composed of light elements such as MgH2, Metal-N-H, Metal-C-H and Metal-B-H (Metal=Li, Na, Mg, Ca) for automobile applications. Particularly, our recent research results on H-storage properties of the metal-N-H system are reviewed in this paper. The mixture of LiH and LiNH2 catalyzed with titanium compound desorbed ~6 mass% of hydrogen in temperature ranges from 150 to 250°C under a He gas flow. However, the hydrogen desorption (H-desorption) temperature at PH2=0.1 MPa was 250°C which is too high for on-board applications. We investigated the H-desorption mechanism in the reaction from LiH+LiNH2 to Li2NH+H2 by Thermal Desorption Mass Spectroscopy (TDMS) and Fourier Transform Infrared (FT-IR) analyses for the products replaced by LiD or LiND2 for LiH or LiNH2, respectively. The results indicated that the H-desorption reaction progresses through two-step elementary reactions mediated by ammonia. On the basis of the ammonia mediated model, we successfully designed a new Li-Mg-N-H system composed of 8LiH and 3Mg(NH2)2. The mechanically milled composite desorbed ~7 mass%H2 in range from 120 to 200°C and the H-desorption pressure was higher than 5 MPa at 200°C, being suitable for on-board applications. Moreover, for understanding the role of titanium compounds as catalysts, the chemical state of the titanium compounds doped in the mixture was examined by X-ray Absorption Near-Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) measurements.
抄録全体を表示PDF形式でダウンロード (510K) -
玄道 俊行, 西口 勝也, 麻川 元康2006 年 70 巻 11 号 p. 870-873
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーSpot friction welding (SFW) is a cost-effective spot joining technology for aluminum sheets, capable of delivering better quality compared with resistance spot welding (RSW). In this study, this technology is applied to the joining of steel and aluminum together. The fusion welding between steel and aluminum is known to be difficult for sufficient strength due to the formation of brittle intermetallic compounds. SFW is a solid state, low temperature joining process using friction heat, so that it's possible to prevent the formation of brittle intermetallic compounds in the joints between steel and aluminum. Tensile shear test was conducted and the joint state was investigated by optical microscope and EPMA. Any remaining coating at the joint interface not removed by the plastic flow will prevent a good contact of the fresh surfaces of aluminum and steel. As a consequence, the joint strength decreases due to the difficulty of removing galvanized coatings with high solidus temperature. In addition, investigation result of steel SFW is also introduced.
抄録全体を表示PDF形式でダウンロード (737K) -
仲井 清眞, 小林 千悟, 濱田 昌彦, 小溝 裕一2006 年 70 巻 11 号 p. 874-879
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーIntragranular bainite (α), which consists of 24 variants formed at random, in steels has been investigated in order to develop both strength and toughness. The orientation relationship, {011}α//{111}γ, <111>α//<101>γ and <211>α//<121>γ, between intragranular bainite and austenite (γ) has been analyzed to be an important controlling factor for toughness. It could be suggested that the increase in the number density of nucleation site for lath of intragranular bainite increases in both strength and toughness of bainitic steels.
抄録全体を表示PDF形式でダウンロード (1255K) -
井上 宜治, 菊池 正夫, 天藤 雅之, 梶村 治彦2006 年 70 巻 11 号 p. 880-889
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーEffects of Al content on oxidation behaviors of Al-containing 18 mass%Cr stainless steels, which are used for catalysis substrate in motorcycle mufflers, were investigated both in an exhaust gas atmosphere and in air at temperatures from 873 to 1373 K. The specimens with more than 2 mass%Al exhibit excellent oxidation resistance at 873-1373 K because the Al2O3 layer formed at the top surface acts as protective film against oxidation. Weight gain during oxidation is largest in the specimens having about 1 mass%Al in exhaust gas at temperatures higher than 1073 K. It is considered to be caused by the formation of the Cr-Al depleted zone between the Cr2O3 layer at the top surface and the discontinuous Al2O3 layer in the base metal. Red scale oxidation is observed only in the specimen with 1.6 mass%Al at 973 K in exhaust gas. This phenomenon can be explained by the same mechanism as the oxidation behavior observed in the 1 mass%Al-containing specimens at temperatures higher than 1073 K.
抄録全体を表示PDF形式でダウンロード (1673K) -
堀川 敬太郎, 日岡 健一郎, 小林 秀敏2006 年 70 巻 11 号 p. 890-896
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーHydrogen accumulation during bending of Al-Mg-Si alloys for automotive body panel was visualized by means of hydrogen microprint technique in comparison with the stress and strain localization simulated by finite element method. Silver particles representing the site of hydrogen emission were arranged at the grain boundaries and slip lines when the specimen was bended at 170° degree. Hydrogen accumulation was increased when the bending pattern was changed from the 170° bending to the full bending. It was also revealed that hydrogen was preferentially accumulated at the tension side of the specimen after the full bending.
抄録全体を表示PDF形式でダウンロード (1348K) -
中川 惠友, 金谷 輝人, 長岡 紀幸, 榊原 精, 伊藤 吾朗2006 年 70 巻 11 号 p. 897-904
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーFatigue crack initiation and propagation have been investigated in relation to the aged microstructure in an Al-4%Ge alloy by means of a fatigue test, microstructural characterization, and fractography. Specimens were solution-treated at 693 K, quenched in iced water, kept at 273 K for 60 s, aged at 473 K for times up to 72 ks and then fatigue-tested. It was confirmed that as the aging time increases, the tensile strength initially increases, reaches a maximum, and then decreases, while the fatigue strength monotonously decreases. Both in the interior and at the surface of the specimen, as the aging proceeded, the growth of precipitates inside the grain as well as on the grain boundary was observed while the width of precipitate free zones (PFZs) adjacent to the grain boundary was almost constant. Fractographic observations showed that intergranular fracture became predominant with increasing aging time and decreasing stress amplitude. From this result and close observations of the fatigue cracks initiation sites, the cracking was deduced to proceed in the following steps: 1) cracks initiate in the intergranular region of the specimen surface, 2) the cracks propagate along the intergranular region towards the interior of the specimen, 3) the crack path transits to the transgranular region because of the increase in true stress, 4) ductile fracture occurs with a marked reduction in area. The crack initiation was presumed to occur as a result of intrusion and extrusion formations along the soft PFZs that play a similar role to that of the persistent slip bands in most metallic materials.
抄録全体を表示PDF形式でダウンロード (1468K) -
松木 一弘, 崔 龍範, 有田 和司, 山中 隆志, 佐々木 元, 柳沢 平2006 年 70 巻 11 号 p. 905-911
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーThe relation between infiltration displacement in a preform and time were measured in infiltration experiments using a simply shaped Fe-Cr-Si preform with a small size and A336.0 molten alloy under the conditions of the temperature range of 973-1073 K and low pressure of 0.4 MPa. The permeability coefficient was estimated from this relation and its value showed the temperature dependence. In contrast, pressure distribution of the molten alloy in a complex preform with a large size was calculated on the basis of Darcy's law using the permeability coefficient estimated in this study. The infiltration behavior which could be estimated from the calculated pressure distribution of the molten alloy, agreed with that obtained from the practical infiltration. The period showing an end of the infiltration in the preform was same in both results of simulation and experiment. It is found that the pressure distribution of the molten alloys in preforms can be estimated by this calculation method using the permeability coefficient obtained from the infiltration displacement and time, regardless of a kind, size or porosity of preforms and a kind or temperature of molten metals.
抄録全体を表示PDF形式でダウンロード (1165K) -
日野 実, 村上 浩二, 水戸岡 豊, 平松 実, 住岡 誠二, 金谷 輝人, 西條 充司2006 年 70 巻 11 号 p. 912-917
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーThe environmental friendly anodizing was carried out using a mainly phosphate solution without heavy metal onto AZ91D magnesium alloy. The effects of the anodizing on mechanical properties were examined using a tensile test and hardness tester. The tensile test revealed that the anodic oxide coatings less than 10 μm in thickness appear not to lower the tensile strength. The hardness of AZ91D substrate with the coatings less than 10 μm in thickness after anodizing increased, and this tendency was remarkably recognized near the surface. This surface hardening is considered to be due to the rise in the temperature of the specimen of surface side and the resulting solution treatment brought by dielectric breakdown during anodizing. These results demonstrate the advantage of this anodizing for the application of the structural material in such as the automotive field.
抄録全体を表示PDF形式でダウンロード (1441K) -
曽田 繁利, 児玉 敏康, 伊藤 正樹, 野口 浩幸, 北川 裕之, 長谷崎 和洋, 野田 泰稔2006 年 70 巻 11 号 p. 918-923
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーThe large thermopower maximum observed for the bismuth antimony (Bi88Sb12) alloy as a function of temperature, is studied based on the multi-carrier model using the Boltzmann transport theory and Fermi integration. The chemical potential of this system has been initially calculated at each temperature from the observed Hall coefficient data. It was observed that the calculated chemical potential remains close to the bottom of the conduction band at low temperatures, and then increases at T=70 K, where the thermopower maximum is observed. The calculation also showed a similar maximum at this temperature. From the calculated results, the temperature dependence of the thermopower is associated with the transition between extrinsic conduction and intrinsic conduction, and thus the Bi88Sb12 alloy is recognized as a strongly degenerate semiconductor.
抄録全体を表示PDF形式でダウンロード (346K) -
冨川 貴志, 須賀 茂幸, 和田 仁志, 金武 直幸2006 年 70 巻 11 号 p. 924-928
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーThe sliding bearings for diesel engines include Pb, which is one of environmentally hazardous substances and the usage will be limited in near future. Therefore, the Pb free bearing which consists of pure Sn overlay and Cu-5 mass%Sn-1 mass%Ag sintered lining was developed. After engine bench test of the bearing, Cu-Sn intermetalic compounds are formed at the interface between Sn overlay and Cu alloy lining. Total thickness of the Cu-Sn intermetalic compounds is proportion to square root of time and is not affected by oil and pressure. In the results of a seizure test under local contact condition, the heat treated bearings which had intermetalic compounds layer, had approximately the similar seizure resistance to the bearings without intermetalic compounds. There is no problem by formation of the Cu-Sn intermetalic compounds.
抄録全体を表示PDF形式でダウンロード (700K) -
王 栄光, 木戸 光夫, 鈴村 文寛, 向井 弘治2006 年 70 巻 11 号 p. 929-935
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーThe volume influence of aqueous sulfuric acid solution on the corrosion rate of pure iron during the initial 0.6ks was investigated by potentiostat, digital microscope and atomic force microscope (AFM). Three types of solution volume on the specimen, bulk solution, macro-droplet with millimeter size and micro-droplet with micrometer size, were used.
A micro-droplet with diameter of 1~10 μm can be produced on a pre-assigned target micro-zone of specimen by the cantilever tip of AFM. The corrosion behavior by the droplet can be investigated using both the contact mode and the AC non-contact mode of AFM. The corrosion rate in bulk solution was much higher than that in a micro-droplet of sulfuric acid solution. In the case of corrosion on pure iron surface caused by a micro-droplet, the corrosion rate was smaller for the smaller droplet. The solidification of the micro-droplet in 25-30%RH condition is faster than that in 50-70%RH condition.
抄録全体を表示PDF形式でダウンロード (1122K) -
伊藤 誉, 早田 圭吾, 杉本 隆史2006 年 70 巻 11 号 p. 936-939
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーThe purpose of surface modification of titanium and its alloys is the formation of a stiffening layer and in the improvement of seizure. If the surface layer is an anatarse type TiO2, photocatalysis can occur in titanium alloys. The substrates used in this study were CP-Ti, α+β type Ti-6Al-4V, and β type Ti-15V-3Cr-3Sn-3Al. In the pretreatment, an alkaline-titanate layer was integrated with the substrates through 5 kmol•m-3-NaOH or -KOH treatments at 333 K for 345.6 ks. Since the oxidizing was done in a suitable atmosphere and temperature, photocatalysis occurred via ultraviolet irradiation along with that generated by the anatarse type TiO2. The photocatalysis of the α type alloy that generates anatarse type TiO2 easily is superior to that of the β type alloy. In addition, the α+β 2 phase structure alloy was superior in photocatalysis to the α single phase alloy.
抄録全体を表示PDF形式でダウンロード (684K) -
伊藤 慶祐, 神田 昌枝, 西 義武2006 年 70 巻 11 号 p. 940-944
発行日: 2006年
公開日: 2006/11/22
ジャーナル フリーA composite polymer, that large amount of 18-8 stainless steel powder (SUS304) was homogeneously dispersed in Nylon6 matrix, has been prepared. The homogeneous dispersion from 0 to 30 vol% of the 18-8 stainless steel powder decreases the Charpy impact value of the composites. However, the homogeneous dispersion from 30 to 40 vol% of the alloy doesn't largely decrease the impact value. In addition, the 18-8 stainless steel particles dispersion enhances the specific weight (heavy), workability and appearance.
抄録全体を表示PDF形式でダウンロード (996K)
- |<
- <
- 1
- >
- >|