巻号一覧
57 巻, 3 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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山本 厚之, 寺下 誠, 椿野 晴繁2007 年 57 巻 3 号 p. 99-104
発行日: 2007年
公開日: 2007/07/31
ジャーナル フリーA new technique for improving mechanical properties in magnesium alloys was developed by the authors, in which specimens are repeatedly hot-pressed using wavy surface dies with in-plane rotating. A solid lubricant, h-BN, has been used and the size of the waves has been changed. Specimens of AMCa602 and AZ31B magnesium alloys were hot-pressed at 623 K for eight times with rotating at 45 degree after each pressing. The treated specimens showed that intensities in accumulation of basal plane in pole figures were decreased and the orientation of accumulation was diffusely scattered, compared with those obtained on solution heat treated specimens. And also, an anisotropy in mechanical properties disappeared to show low yield stress and high work hardening rate.抄録全体を表示PDF形式でダウンロード (5479K) -
木下 勝之, 大﨑 修平2007 年 57 巻 3 号 p. 105-111
発行日: 2007年
公開日: 2007/07/31
ジャーナル フリーFor excess Si type Al–Mg–Si alloys with different (coarse or fine) grain sizes, impact tensile tests by a split-Hopkinson bar method have been carried out using sheet specimens with two kinds of aspect (width/thickness) ratio. The impact tensile strength of the coarse alloy is higher than the static one, while that of fine alloy is lower. The elongation, however, is lower than the static one independently of alloy or specimen size. The decrease in the elongation is found to correspond to the increase in intergranular area on fracture surface. The specimen with the aspect ratio of 3 is not suitable to be used as the impact tensile specimen.抄録全体を表示PDF形式でダウンロード (1881K) -
青沼 昌幸, 津村 卓也, 中田 一博2007 年 57 巻 3 号 p. 112-118
発行日: 2007年
公開日: 2007/07/31
ジャーナル フリーPure titanium and AZ31B magnesium alloy sheets were butt joined by friction stir welding method (FSW) with different joining parameters by tool rotating speed and changing probe position from the joint interface. Al-rich titanium layer with under 2 μm in thickness was formed at a joint interface in pure titanium side in the following FSW conditions (travel speed: 300 mm/min, tool rotating speed: 1500 rpm , probe position: 1.2 mm into titanium). Near the joint interface, the grain of titanium was deformed by both heat effect and stirring force , and vickers hardness of titanium increased to 200 HV 0.05 in comparison with base metal hardness 150 HV 0.05 because of work hardening. However AZ31B showed no obvious hardness change. Tensile strength of the joint increased with changing the prove position into the titanium side and the maximum strength 156 MPa was obtained at probe position of 1.2 mm into titanium side. Fracture occurred in the stir zone of AZ31B.抄録全体を表示PDF形式でダウンロード (2981K) -
徳田 健二, 熊井 真次, 鈴木 健太, 宮崎 武, 石原 暁子, 永田 雄介, 羽賀 俊雄2007 年 57 巻 3 号 p. 119-124
発行日: 2007年
公開日: 2007/07/31
ジャーナル フリーInfluence of casting conditions on the occurrence of internal cracks for 6022 aluminum alloy fabricated by high-speed twin roll-caster was investigated. The caster used in the study was equipped with a pair of water-cooled, pure copper rolls, and a cooling slope upstream of the rolls. The strips exhibited a common microstructural feature. Columnar grains grew from both surfaces of the strip, and they were gradually replaced by equiaxed grains. In the mid-central region, a band of fine grains was observed. Such fine grains seemed to originate from the crystallized α-Al dendrites on the cooling slope or the roll surfaces. Internal cracks were observed in the 6022 aluminum alloy strip that was subjected to the highest cooling rate. The cracks were located between equiaxed grains and fine grains at the mid-central region. It was thought that the crack was caused by a lack of liquid supply at the mid-central region where the solidified shells meet together. The cracks were reduced without using cooling slope, with decreasing casting load and lowering metal head. A slight reduction in the cooling rate and reduction of α-Al generation were effective for obtaining sound 6022 aluminum alloy strips.抄録全体を表示PDF形式でダウンロード (2270K) -
村上 浩二, 日野 実, 平松 実, 長村 光造, 金谷 輝人2007 年 57 巻 3 号 p. 125-130
発行日: 2007年
公開日: 2007/07/31
ジャーナル フリーThe present authors have conducted characterization of zincate films formed as a pretreatment for electroless nickel-phosphorus coatings on commercial pure aluminum substrate (JIS A1050P-H24, 99.5 mass%Al). By using a basic solution which consisted of sodium hydroxide and zinc oxide, a zincate film formed by single zincate treatment showed coarse zinc grains of 1–2 μm in size whose (0001) planes were mainly parallel to the surface of the substrate. A double zincate treatment by using the basic solution reduced the coarse grains, and the thickness of the uniform zincate film was 30–40 nm. A commercial zincate solution which contained iron decreased the number and the size of coarse zinc grains for the single zincate treatment compared with the case of the basic solution, and the double zincate treatment formed a further thin zincate film of 10–20 nm in thickness. The single zincate treatment by using the basic zincate solution resulted in such poor adhesive strength of the electroless nickel–phosphorus plated film as to peel off the substrate due to its residual stress. Quantication of adhesive strength by 90° peeling test showed the double zincate treatment increased the adhesive strength of the plated film up to 30 N/m. In the case of the commercial zincate solution, the adhesive strength obtained by the single zincate treatment was 125 N/m. Furthermore, the adhesive strength of the plated nickel–phosphorus film was too high to conduct the peeling test in the case of the double zincate treatment by the commercial solution, where dimple patterns were observed due to ductile fracture of the substrate. Observation by transmission electron microscopy of the interface between the nickel–phosphorus plated film and the substrate showed gaps in the case of the double zincate treatment by the basic zincate solution. On the other hand, the double zincate treatment by the commercial solution eliminated gaps and a strong interface was obtained.抄録全体を表示PDF形式でダウンロード (1580K)
解説：小山田記念賞
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谷畑 昭人, 佐藤 奈緒子, 勝俣 耕二, 白石 隆, 織田 和宏, 遠藤 修2007 年 57 巻 3 号 p. 131-136
発行日: 2007年
公開日: 2007/07/31
ジャーナル フリーPDF形式でダウンロード (3616K)
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