巻号一覧
48 巻, 12 号
選択された号の論文の8件中1～8を表示しています
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研究論文
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須永 正子1998 年 48 巻 12 号 p. 597-602
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーThe age-hardening behavior at various temperatures up to 453 K of the 7003 aluminum alloys with different compositions was studied by differential scanning calorimetry and transmission electron microscopy. The age-hardening behavior was affected by the amount of Zn and/or Mg contents. The incubation period of the age-hardening process became shorter and the peak hardness became higher with increasing the amount of Zn and/or Mg. The effects of Mg addition on the decreased incubation period and the increased peak hardness were greater by 2 to 7 times than those of Zn addition, compared in a unit mol%. The increase in Mg content at constant Zn concentration in Al–Zn–Mg alloys results in the increased amount of metastable precipitates with higher density and finer size. The increased amount of Mg, therefore, is effective to increase the age-hardenability of Al–Zn–Mg alloys.抄録全体を表示PDF形式でダウンロード (1227K) -
清水 和紀, 松岡 信一, 山崎 申之, 沖 善成1998 年 48 巻 12 号 p. 603-607
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーThis study is described the cutting method using an articulated robot that is the new machining for extruded aluminum alloys. The characteristics of this method are using the small diameter of endmill which aims to reduce the cutting force in order to compensate completely the low stiffness of articulated robot, and using the high-speed spindle to improve the machining efficiency. The behavior of super high-speed rotational cutting for extruded aluminum alloys is still unclear. In this paper, the basic cutting experiments and the structural analysis were done. It was proved the high frequency vibration proper to high-speed cutting had a close relation to the stiffness (natural frequency) of machine tools and workpieces, and great affected the cutting force and the cutting surface. The articulated robot was low stiffness, so there was few effect on the high frequency vibration in cutting, and the cutting force decreased 50~70% in comparison with the fluting machine. Consequently, it was understood the cutting method using an articulated robot was effective for the improvement of high-speed cutting.抄録全体を表示PDF形式でダウンロード (1014K) -
水野 兼雄, 横田 成昭, 廖 菲菁, 福迫 達一1998 年 48 巻 12 号 p. 608-612
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーThe tensile strength and structure (dendrite arm spacing or D.A.S) of cylindrical castings were determined for specimens with different thicknesses and masses subjected to the T6 solution treatment, because they are expected to be affected by the casting modulus (volume/surface area) and the cooling rate (solidification time). When V/S of the castings increases, the cooling rate and the strength decreased, but D.A.S increases. The strength and D.A.S can be presented as a function of the nth power of the casting modulus (V/S).抄録全体を表示PDF形式でダウンロード (586K) -
羽賀 俊雄, 石原 勝之, 片山 剛, 西山 丈司1998 年 48 巻 12 号 p. 613-617
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーIn this study, it is shown that the contacting pressure between roll and melt, and roll speed are important conditions in melt drag roll casting of the aluminum alloy strip. Melt drag process was used as roll caster in this study. Contacting pressure was controlled by melt height in the nozzle. Melt height was set at 10, 20, 30 mm. Roll speed was test in the range of 20~50 m/min. Effect of the two kinds of conditions on defect on the strip surface, and heat transfer coefficient between strip and roll was investigated. Defect on the strip surface is caused when metallostatic pressure is lower than lower limit pressure. Lower limit metallostatic pressure increases with increasing roll speed. Heat transfer coefficient was calculated from solidification time and strip thickness by one dimensional finite differential method. Heat transfer coefficient decreases with casting time. Heat transfer coefficient is divided into two regions. In the first region, heat transfer coefficient decreases rapidly, and it decreases gradually in the second region. In the first region, heat transfer coefficient increased with increasing contacting pressure, but decreased with roll speed.抄録全体を表示PDF形式でダウンロード (869K) -
大参 達也, 松浦 清隆, 工藤 昌行, 伊藤 洋一1998 年 48 巻 12 号 p. 618-623
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーThe mixing-crystallization model has been used to evaluate the effects ofthe convective mixing on the undercooling and solidification behavior of a hypereutectic Al–Si alloy during the mixing process of two different molten alloys: the first melt (Al–12 mass%Si alloy) and the second melt (Al–32 mass%Si alloy). This model treats the mixing of these alloys in stretching lamellar configurations to consider the interactions between the fluid clumps ofthe second melt. The obtained results are summarized as follows: (1) The undercooling of the second melt in the lamellar configurations are smaller than that in the single slab configuration because of the interactions between the second melt lamellar. (2) The number of primary crystals is maximized at a certain strain rate of stretching lamellar depending on the initial melt-distribution. Therefore, excessive agitation during the initial stage of the solidification may depress the refinement of the primary crystals. (3) Nonuniform distribution of lamellar thickness is effective for the crystal refinement compared with the uniform one.抄録全体を表示PDF形式でダウンロード (910K) -
本居 徹也, 福岡 潔, 吉田 英雄1998 年 48 巻 12 号 p. 624-628
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーIt is observed that α–AlFeSi nodules during the solidification in pure aluminum. Assuming that this phase particles form in hydrogen bubbles during the solidification, the following experiments were done: 1) the observation of structures of α–AlFeSi nodules, 2) the effect of hydrogen bubbles on the formation of α–AlFeSi nodules. As a result, it became clear that the morphology of α–AlFeSi nodules, which forms during solidification is a spherical shape with a hollow shell. This structure indicates that α–AlFeSi particles nucleate on the inner wall of the hydrogen bubbles which evolve during solidification. Furthermore, the size and density of α–AlFeSi nodules changed with the cooling rate of solidification and their variations agreed with those of the hydrogen bubbles. It is considered that the above results support the hypothesis, that α–AlFeSi particles nucleate on the innner wall of hydrogen bubbles.抄録全体を表示PDF形式でダウンロード (2192K) -
松木 賢司, 恵利 有司, 會田 哲夫, 高辻 則夫, 楠井 潤, 村上 哲1998 年 48 巻 12 号 p. 629-634
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーMechanical grinding (MG) of air atomized Al–3Fe–3Ni–3Cr–0.7Zr (in mass%) alloy powder was performed with a vibrational ball mill for various times up to 154.8 ks in an argon atmosphere. Subsequently, MG powders as well as atomized powder were hot extruded to rectangular bar shapes (20 mm in width and 3.5 mm in thickness) at 673 K. The effect of MG time on the mechanical properties of extrudates up to 673 K and on the microstructures of MG powders and extrudates was investigated. Vickers hardness of MG powders increased to about 300 with increasing of MG time up to about 30 ks. The results of DSC, XRD and TEM revealed that the primary intermetallic compounds in atomized powder were finely ground and dispersed by MG. The results also suggest that elements consisting of the compounds were dissolved in the matrix beyond their equilibrium solubility by prolongation of MG time. MG and subsequent hot extrusion processes at 673 K resulted in giving extremely fine sub-grains. On boundaries or interior of the sub-grains, the transition elements dissolved in the matrix by MA were precipitated finely as Al3Fe, Al3Ni and Al13Cr2 phase particles. The tensile strength at ambient temperature and at 573 K were about 431.9 MPa and 208.7 MPa for extrusion specimen from atomized powder, and 675.7 MPa and 281 MPa for extrusion specimen from 154.8 ks-MG powder, respectively. However, the ductility was poor in MG materials. Improvements in the mechanical strength are mainly attributed to the presence of extremely fine sub-structure and finely dispersed particles which were introduced during MG and extrusion process.抄録全体を表示PDF形式でダウンロード (1267K)
解説
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日野出 憲治1998 年 48 巻 12 号 p. 635-640
発行日: 1998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 (1285K)
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