巻号一覧
51 巻, 7 号
選択された号の論文の7件中1～7を表示しています
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研究論文
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中山 栄浩, 成毛 康一郎2001 年 51 巻 7 号 p. 346-350
発行日: 2001年
公開日: 2007/03/30
ジャーナル フリー6061 aluminum alloy was aged and tensile tested in order to investigate the effect of the microstructure changes on the serration of the stress-strain curve. The serration was clearly observed for the solution treated specimen and disappeared gradually with proceeding of aging. Stress drops like a sawtooth became small at the first stage of aging treatment and then the serration disappeared with increasing the critical strain, while no noticeable changes in stress fluctuation like a swell. The aging treatment at temperatures below 298 K eliminated the serration by forming clusters, and the aging at temperatures above 353 K eliminated the serration by generating G.P. zones.抄録全体を表示PDF形式でダウンロード (507K) -
権 湧宰, 小橋 眞, 長 隆郎, 金武 直幸2001 年 51 巻 7 号 p. 351-355
発行日: 2001年
公開日: 2007/03/30
ジャーナル フリーAluminum matrix composites reinforced by TiB2 particles which were formed in situ by a combustion reaction between titanium and boron were fabricated from powder mixture of Al, Ti and B. The compacted powder mixtures were led to the combustion reaction by an ignitor with and without preheating. The effects of the powder mixing ratio, porosity of a green compact and preheating on the combustion reaction for the Al–Ti–B system were investigated. The aluminum matrix composites including 30 to 60vol% TiB2 could be fabricated by the combustion reaction without preheating, but some macroscopic cracks were occurred in the composites except for the Al–50 vol%TiB2. The relatively large porosity and preheating before the combustion reaction were effective to the self-propagation of the combustion reaction and microstructure of the synthesized composites, especially in the low volume fraction of TiB2. The reaction between a titanium and a boron in the Al–Ti–B system was initiated after melting of an aluminum.抄録全体を表示PDF形式でダウンロード (543K) -
椿野 晴繁, 石原 右近, 山本 厚之2001 年 51 巻 7 号 p. 356-360
発行日: 2001年
公開日: 2007/03/30
ジャーナル フリーPrecipitation sequence in high purity Al–250 ppm Ni alloy aged at various temperatures ranging from 253 to 823 K was studied by means of resistivity measurements and transmission electron microscopy. On aging at temperatures below about 600 K, the resistivity decreased in three stages accompanying aging time. The first stage was attributed to the annihilation of quenched-in vacancies, and the second and third stages were attributed to the precipitations of metastable phase Al9Ni2 and stable phase Al3Ni, respectively. However, above 600 K, the resistivity decreased apparently in one stage, which was attributed to the precipitation of Al3Ni. The TTP diagram obtained from resistivity changes was constracted from two C-curves which intersected at about 600 K. This temperature will give the upper limit of the formation of metastable phase. By using 0, 100 and 250 ppm Ni alloys, the relationship between as-quenched resistivity and Ni content and, furthermore, the solvus curve of Ni in Al were given.抄録全体を表示PDF形式でダウンロード (489K) -
戸田 裕之, 高橋 明宏, 小林 俊郎2001 年 51 巻 7 号 p. 361-367
発行日: 2001年
公開日: 2007/03/30
ジャーナル フリーThe present work is aimed at experimental evaluation of the effects of damage evolution at coarse intermetallic particles in Al–Li–Cu–Mg alloy, with particular attention on fracture toughness. To vary volume fraction of the particles, various thermo-mechanical treatments have been applied. Strength, ductility and fracture toughness decrease with the increase in volume fraction from 1.2 to 2.2%. Especially, σ0.2 and crack propagation resistance are significantly affected. In-situ SEM observation of the fracture toughness test has also been used to characterize damage evolution at the particles and crack propagation behavior. Some types of particles remain intact even adjacent to the fracture surface, while others are extensively fractured far ahead of a crack-tip. A combination of the crack-tip singularity and micromechanics is used to estimate in-situ strengths of the particles. It is concluded that the particle strengths have strong dependence on diameter, and that, due to the existence of the damaged particles, crack deflection and formation of secondary cracks occur in the case of high particle volume fraction. Fracture mechanical analysis reveals that reduction in the crack propagation resistance is attributed to the amplification of mode I crack driving force due to the existence of microcracks. Finally, measured fracture toughness is interpreted utilizing a computer simulation constructed in the previous study. Although individual microstructural factors have only modest effects, competitive and synergistic effects are attributable to the measured large drop in the fracture toughness.抄録全体を表示PDF形式でダウンロード (859K)
研究ノート
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古井 光明, 中村 友則, 佐治 重興2001 年 51 巻 7 号 p. 368-369
発行日: 2001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 (185K)
解説
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福岡 潔2001 年 51 巻 7 号 p. 370-377
発行日: 2001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 (990K)
連載講座
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乳井 辰彰, 服部 哲2001 年 51 巻 7 号 p. 385-391
発行日: 2001/07/30
公開日: 2021/06/30
ジャーナル フリーPDF形式でダウンロード (1661K)
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