巻号一覧
61 巻, 4 号
選択された号の論文の6件中1～6を表示しています
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研究論文
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千葉 浩行, 植木 徹, 鳥山 隆成, 遠藤 至, 小林 昂光, 吉田 誠原稿種別: 研究論文
2011 年 61 巻 4 号 p. 135-141
発行日: 2011/04/30
公開日: 2011/05/31
ジャーナル フリーIt is necessary to obtain the mechanical properties of semi-solid alloy in order to predict the occurrence of solidification cracking, one of the serious casting defects of aluminum alloy die-casting and DC casting, by computer simulation. New in-situ measuring method for mechanical properties on semi-solid aluminum alloy by horizontal tensile test, based on that of Oya and Kitaoka et al., was developed. The strain was determined by measuring the displacement between dendrites defined as the makers. Influence of gage length on the fracture strain was clarified. Fracture strain and tensile strength of semi-solid Al–7mass%Si alloy were obtained.抄録全体を表示PDF形式でダウンロード (3718K) -
村上 浩二, 日野 実, 水戸岡 豊, 金谷 輝人原稿種別: 研究論文
2011 年 61 巻 4 号 p. 142-148
発行日: 2011/04/30
公開日: 2011/05/31
ジャーナル フリーIn order to clarify the mechanism of formation and growth of nodules and whiskers on the leads used in aluminum electrolytic capacitors, aluminum–tin binary alloys were subjected to the investigation as the model alloys for the joints in the leads. The concentration of tin in the binary alloys was 1, 5 or 10 at%. The alloy of 10 at% tin showed the largest number of nodules or whiskers on its polished surface after keeping under ambient conditions for 7.8 Ms. Many whiskers whose length were more than several tens of micrometers were observed in the case of the alloy of 5 at% tin. The alloy of 1 at% tin showed few nodules or whiskers. Growth of nodules and whiskers is caused by difusion of tin atoms from the strained or unstable areas into the stable ones or the root grains. Then, the extrusion toward the surface at the root grains develops nodules and whiskers. As a prevention measure of whiskers, selective etching of the aluminum phase using a solution of sodium hydroxide was confirmed to be successful. Thus the aluminum phase was thought to form a non-uniform distribution of strain in the tin phase. This acts as the driving force in difusion of tin atoms.抄録全体を表示PDF形式でダウンロード (6205K) -
織田 和宏, コマロフ セルゲイ, 石渡 保生原稿種別: 研究論文
2011 年 61 巻 4 号 p. 149-154
発行日: 2011/04/30
公開日: 2011/05/31
ジャーナル フリーThe study purpose is to investigate effects of ultrasonic radiation on refinement of primary Si crystals of hypereutectic Al–Si alloys and to examine the refining effect in die casting. The ultrasonic refining effect was examined by using Al–Si alloys without or with addition of phosphorus. The experiments included melting of alloy in a crucible, radiation of ultrasound into the melt at temperatures at least 60 K higher than the Si crystallization temperature, holding of the melt for 20–80 s and pouring of it into a Cu mold by gravity casting. The refining effect was found to be dependent on P content and holding time. The EPMA investigation revealed that the ultrasonic radiation increases the number of AlP particles acting as heterogeneous sites for the primary Si nucleation. The refining effect was significant at the holding time of 20–50 s. Then, based on the above results, the radiation conditions for the die casting were determined. A key point of the conditions was that the refining effect and melt fluidity are kept at the desired level for a period after the radiation. Microstructural investigation showed considerable refinement of primary Si crystals and Al–Fe–Mn–Si compounds. The ultrasonically treated die castings exhibited an improved tensile strength.抄録全体を表示PDF形式でダウンロード (7921K) -
中村 紀夫, 高木 眞一原稿種別: 研究論文
2011 年 61 巻 4 号 p. 155-159
発行日: 2011/04/30
公開日: 2011/05/31
ジャーナル フリーCommercial purity aluminum (A1070) was subjected to fine particle bombardment (FPB) with 1.0 mass% carbon steel and pure nickel projectile particles. Nanocomposite structures formed at the near-surface region, which contained refined aluminum grains of less than 100 nm in diameter and dispersed projectile fragments several tens of nanometer to several micrometer in size. Beneath the nanocomposite structure was found a fine-grained matrix with approximately 1-μm-diameter grains. Observation of the microstructural transition at the near-surface region suggested that the nanocomposite structures developed via severe plastic deformation (SPD), accompanied by a folding and imposing of the convex part of the surface, and by mechanical mixing with the fragments of the projectile particles. The nanocomposite structures exhibited high hardness values of approximately HV200, which are superior to those of extra-super duralumin (A7075-T6). The relationship between the grain size and hardness value in the structures corresponds well to the Hall–Petch relationship extrapolated from previous studies. Therefore, the increase in hardness is thought to be mainly the result of grain refinement strengthening.抄録全体を表示PDF形式でダウンロード (4410K)
解説
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生貝 初, 兼松 秀行, 黒田 大介原稿種別: 解説
2011 年 61 巻 4 号 p. 160-166
発行日: 2011/04/30
公開日: 2011/07/30
ジャーナル フリーPDF形式でダウンロード (12276K)
連載講座
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兒島 洋一2011 年 61 巻 4 号 p. 167-178
発行日: 2011/04/30
公開日: 2023/01/30
ジャーナル フリーPDF形式でダウンロード (4849K)
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