巻号一覧
52 巻, 9 号
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研究論文
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小川 誠, 安田 俊司, 嵯峨 常生2002 年 52 巻 9 号 p. 387-391
発行日: 2002年
公開日: 2007/03/30
ジャーナル フリーThe chip in the magnesium alloy cutting process often burns, when a chip thickness decreases with the stopping of tool feed at the end of cutting, or the thin chip is formed at the finishing. In this paper, the prevention and the causes of ignition and combustion of chip in turning of AZ91 magnesium alloy casting has been studied in terms of the surface properties of chip, the records of cutting force, cutting temperature and the sharpness of edge. The results obtained are as follows. It becomes clear that temperature increase with an oxidation reaction on the chip surface affects most for the combustion. Therefore, the chip combustion occurs depending mainly on the ratio S/V (surface area per unit volume). The safety cutting without the chip combustion is performed at satisfying the above ratio under one over two hundred (1/200 mm) on the cutting condition and by the using of the bits with sharp edge such as cBN or diamond tool.抄録全体を表示PDF形式でダウンロード (465K) -
山本 勇, 向山 友彦, 坂下 勝則2002 年 52 巻 9 号 p. 392-397
発行日: 2002年
公開日: 2007/03/30
ジャーナル フリーIt is believed that there exists a close relationship between the deformation on fracture surface and the fracture toughness. On the ductile fracture surface, it is known that macroscopic deformation called shear lip or plastic hinge is observed. In addition, microscopic deformation reflecting minute variation of geometry like fracture surface area is also associated with toughness. In this paper, measurement of fracture was performed by laser displacement meter and scanning laser microscope. Using these devices, instead of conventional planar measurement method, fracture surface can be measured stereoscopically. The macroscopic deformation, microscopic deformation, volume of shear lip and fracture surface area were determined, respectively. Therefore, it enables the investigation of the relationships between toughness at loading speed from 8.3 × 10−6 m/s to 8 m/s and these fracture surface features on 6061–T651 aluminum alloy. The results demonstrated that there is a good agreement between the variation of loading speed for toughness testing and the total fracture surface area.抄録全体を表示PDF形式でダウンロード (406K) -
松田 健二, 木戸 耕介, 谷口 昇平, 上谷 保裕, 池野 進2002 年 52 巻 9 号 p. 398-402
発行日: 2002年
公開日: 2007/03/30
ジャーナル フリーAge-hardening behavior of the Al–Mg–Si alloys added with (chromium + iron) and copper were investigated by hardness measurements and high-resolution transmission electron microscopy (HRTEM) . Age-hardenabilities of the alloys aged at 423 K increased with excess Si or Mg2Si contents. Cu addition increased their age-hardenability, whereas the addition of (Cr + Fe) decreased peak hardness. At the peak hardness in Cu-bearing alloys, the mean size of precipitates was smaller and the number density of precipitates was higher than those in Cu-free alloys. (Cr + Fe)-bearing alloys included AlSi(Cr, Fe) and AlSiFe dispersoids, which had depleted zones around them, and the number density of precipitates decreased in those alloys. Decrease in the number density of precipitates might be explained by consumption of solute atoms by the formation of dispersoids. It was confirmed that the Random-type precipitates existed in alloys aged at 423 K up to the peak hardness by HRTEM observation.抄録全体を表示PDF形式でダウンロード (440K) -
古井 光明, 関口 誓子, 前 健彦, 佐治 重興2002 年 52 巻 9 号 p. 403-409
発行日: 2002年
公開日: 2007/03/30
ジャーナル フリーGrain refinement by inducing large amount of deformation strain at very low temperature restricted a recovery and annealing subsequently, is an effective method to develop an aluminum alloy with fine grain. In paticular, a two-directional rolling at very low temperature is very effective method compared with a one-directional rolling at room temperature. However, recovery and recrystallization behavior during static annealing for aluminum alloys severely rolled by two-directionally at very low temperature is not clear. In the present work, 3004 and 5083 aluminum alloys were two-directionally rolled to 80% reduction in area at liquid nitrogen temperature and were subsequently annealed for various temperatures and times. The recovery and recrystallization was investigated by hardness and microstructure changes compared with one-directional rolling at room temperature. In 3004 and 5083 aluminum alloys annealed at from 498 K to 623 K for short time, softening ratio of two-directionally rolled specimen at liquid nitrogen temperature was larger than that of one-directionally rolled specimen at room temperature. After long time annealing, order of softening ratio was reversed. For both the alloys average grain size after primary recrystallization was smallest at 623 K annealing and was increased with decreasing annealing temperature. The grain size after primary recrystallization obtained by two-directional rolling at liquid nitrogen temperature was refiner than that obtained by one-directional rolling at room temperature at all annealing temperatures. In either rolling method and all annealing temperatures, softening ratio of 5083 alloy was larger than that of 3004 alloy and the grain size after primary recrystallization of 5083 alloy was smaller than that of 3004 alloy.抄録全体を表示PDF形式でダウンロード (591K) -
椿野 晴繁, 野上 敦司, 寺澤 倫孝, 三田村 徹, 山ノ井 智明, 木野村 淳, 堀野 裕治2002 年 52 巻 9 号 p. 410-416
発行日: 2002年
公開日: 2007/03/30
ジャーナル フリーThe surface segregation of lead in the high-purity aluminum foils containing a small amount of lead annealed at various conditions was studied by Rutherford back scattering spectroscopy (RBS) and transmission electron microscopy (TEM). The foils containing 0.13 and 13 at-ppm Pb were annealed for 1.8~72 ks at 473~923 K. The annealing at higher temperature and for longer time enhanced segregation of the lead at foil surface region, but TEM-EDS revealed that most of the lead segregated not to the aluminum surface but to the oxide film formed by heat treatment. The oxide film was amorphous phase in all the heat-treated foils. The oxide compositions ranged from 20 to 50 at% Pb, from 10 to 50 at% O and remained Al depending on the position. The surface segregation process was discussed.抄録全体を表示PDF形式でダウンロード (505K) -
八太 秀周, 松田 眞一, 吉田 英雄2002 年 52 巻 9 号 p. 417-420
発行日: 2002年
公開日: 2007/03/30
ジャーナル フリーThe creep behavior of 3003 aluminum alloy extrusions with various manganese contents in solid solution and different microstructures was investigated. Yield stress decreases with heat treatment time at 400°C both fibrous and recrystallized structures. These microstructures do not change during annealing. Specimen with high manganese contents in solid solution shows higher creep strength than that with low manganese contents even if yield stress are same at 200°C. Further, in the same manganese contents in solid solution, the specimen with the fibrous structure shows higher creep strength than the recrystallized one due to subgrain structure.抄録全体を表示PDF形式でダウンロード (450K) -
山崎 晃弘, 金子 純一, 菅又 信2002 年 52 巻 9 号 p. 421-425
発行日: 2002年
公開日: 2007/03/30
ジャーナル フリーWith a purpose of synthesizing dispersion strengthened Mg–based materials, powders of pure Mg and Mg–Al (AZ91) alloy were mechanically alloyed with addition of metal oxide (MnO2 and Fe2O3). After mechanical alloying, the powders were consolidated by vacuum hot pressing and hot extrusion. Solid state reactions in the mechanically alloyed powders and extruded materials were studied by XRD and TEM. In all systems, the solid state reactions started during mechanical alloying and progressed during subsequent heat treatment. In Mg–Al– metal oxide systems, added MnO2 and Fe2O3 were decomposed and formation of MgO and intermetallic aluminide compounds occurred. In the as-extruded materials, fine magnesium matrix grains of 100~200 nm in size were observed, and those extremely fine compounds of less than 20 nm in size were dispersed in the magnesium matrix. In Mg–Al–MnO2 system, the 0.2% proof stress and specific strength of the as-extruded material in compression test were 596 MPa and 305 MPa/ (Mg/m3), respectively.抄録全体を表示PDF形式でダウンロード (476K)
研究ノート
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古井 光明, 茶園 玲, 穴田 博, 佐治 重興2002 年 52 巻 9 号 p. 426-427
発行日: 2002年
公開日: 2007/03/30
ジャーナル フリーPDF形式でダウンロード (233K)
解説
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栗田 洋敬, 山縣 裕2002 年 52 巻 9 号 p. 428-432
発行日: 2002年
公開日: 2007/03/30
ジャーナル フリーPDF形式でダウンロード (415K)
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