巻号一覧
48 巻, 8 号
選択された号の論文の9件中1～9を表示しています
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研究論文
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堀川 敬太郎, 倉本 繁, 菅野 幹宏1998 年 48 巻 8 号 p. 371-374
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーThis work was performed to clarify the sources of trace sodium which caused a high temperature embrittlement of an Al–5 mass%Mg alloy. Various kinds of Al–5 mass%Mg alloys were prepared by using different raw materials and crucibles. Then, sodium contents of the Al–Mg alloys were analyzed with GD–MS. It was proved that sodium was introduced from the 99.97% purity magnesium. Further, it turned out that sodium was also brought from the 99% purity alumina crucible. Hot ductility of these alloys increased with decrease in the sodium content. From sets of experiments, it is clarified that the high temperature embrittlement of an coarse-grained Al–5 mass%Mg alloy disappears when the sodium content is decreased to 0.01 ppm.抄録全体を表示PDF形式でダウンロード (1078K) -
久田 伸彦, 菅又 信, 金子 純一1998 年 48 巻 8 号 p. 375-379
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーWith a purpose of obtaining materials having high specific strength at room temperature and superplastic elongation at elevated temperatures, Mg–Al–Zn ternary alloys with higher contents of alloying elements than the commercial Mg–Al–Zn casting alloys were rapidly solidified by gas atomizing and subsequent splat quenching. The rapidly solidified flakes were consolidated to the P/M materials by hot extrusion at 573 K. The cast ingots of these alloys were also hot-extruded as the reference I/M materials. The obtained P/M materials showed finer dispersion of the second phase particles than the I/M counterparts. The hardness and tensile strength of P/M and I/M materials increased linearly in parallel to each other with increasing Al+Zn content in atomic %. The highest tensile strength of 447 MPa at room temperature was obtained for rapidly solidified Mg–8 mass%Al–12 mass%Zn. The decreases in tensile strength and increases in elongation with rising test temperature were more pronounced in the P/M materials than in the I/M materials. At 573 K, tensile strength of the P/M materials decreased to below 20 MPa and elongation increased to above 100% for a wide range of tensile strain rate. The highest elongation was larger than 900% which was observed at 573 K for the Mg–10 mass%Al–5 mass%Zn P/M material at an initial strain rate of 2 × 10−2/s.抄録全体を表示PDF形式でダウンロード (1244K) -
二宮 崇, 平 博仁, 金武 直幸, 長 隆郎1998 年 48 巻 8 号 p. 380-384
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーHigh strain rate superplastic bulge forming of aluminum alloy matrix composite sheets reinforced by SiC particles was studied and compared to their deformation characteristics in a tensile test. Bulge forming test was performed at elevated temperatures using 36 mm diameter blank disks by gas pressure. The bulge shapes were successfully formed at high strain rate (about 0.1/s) at which superplasticity is observed in the tensile test. The superplastic formability of the composite with 25% volume fraction of SiC particles is better than that with 17% SiC, corresponding to the measured elongation in the tensile test. The limit bulge height of the sheet with the same SiC volume fraction is increased with increasing initial thickness. The higher forming gas pressure, namely the higher forming rate, lead to the uniform thickness distributions of the bulged part. The maximum thickness strain at the top of the bulge and the applied stress calculated from the forming gas pressure in bulge forming can be concerned with the elongation and the flow stress in the tensile test.抄録全体を表示PDF形式でダウンロード (1193K) -
Fumihiro SATO, R. C. NEWMAN1998 年 48 巻 8 号 p. 385-389
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーThe effect of Mg on pitting corrosion of aluminum has been studied in terms of activation, repassivation, in comparison with the effect of Zn. The pitting potential and passive current in 0.5 NaCl were slightly decreased by alloyed Mg, respectively, but the repassivation potential tended to increase. In current transients and open circuit potential measurements, preferential dissolution of Mg, causing an aluminum enrichment, was considered in 6 M HC1 (pit-like solution) . In addition, after immersion in 6 M HC1, the pitting potential increased over the value of pure Al. Therefore, it can be considered that alloyed Mg has little effect to activate aluminum at first, but that aluminum dissolution rate is reduced by an aluminum enrichment caused by the preferential dissolution of Mg in the local environment.抄録全体を表示PDF形式でダウンロード (724K) -
藤野 隆由, 水本 一, 野口 駿雄1998 年 48 巻 8 号 p. 390-394
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーStandard sample is necessary for determination on surface analysis, and particularly it is difficult to make a standard sample for secondary ion mass spectrometry (SIMS). A sample turned ion implantation into is used for a standard sample of quantitative analysis with SIMS, but it is neither simple nor easy to make a standard sample for the analysis of various kinds of samples. The first electrolysis was done with sulfate (H2SO4) bath and trisodium phosphate (Na3PO4) bath, and second electrolysis of tin and nickel was done on the films. The trace metals (Sn and Ni) deposited by second electrolysis was determined by graphite furnace atomic absorption spectrometry (GFAAS), and it was investigated to make the standard sample for the analysis of electrolytic pigmentation coatings on SIMS. The relative sensitivity factor (RSF) was calculated from the film density measured with GFAAS. RSF of 120Sn was 4.63 × 1014 in coating formed with H2SO4 bath, and RSF of 120Sn was 3.142 × 1014 in coating formed with Na3PO4 bath. As the result of the depth profiles by SIMS, the deposition behavior of the metal was different by the kind of first electrolysis baths; the metal deposited along pore wall in H2SO4 bath coating, and the metal accumulated in pore bottom in Na3PO4 bath coating. The distribution of concentration and the deposition behavior of metal was elucidated with SIMS.抄録全体を表示PDF形式でダウンロード (799K) -
田村 洋介, 河野 紀雄, 茂木 徹一, 佐藤 英一郎1998 年 48 巻 8 号 p. 395-399
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリーTo understand the grain refinement mechanisms by C addition and superheating of Mg–Al system alloys, two kinds of experiments were performed. In the first experiment, a commercial AZ91E magnesium alloy was melted and C2Cl6 was added as a carbon nucleant at 1023 K. In the second experiment, normal-purity and high-purity Mg–Al alloys containing 5.6 to 14.1%Al made of 99.9 and 99.99%Mg and 99.99 and 99.999%Al were superheated at 1123 K for 900 s before casting. Metallographic examinations were performed to clarify the solidified structures. In the addition of carbon, rod-like subsance as nucleants could be observed in each grain. EPMA analysis indicated that rod-like subatance was constituted of Al, C and O. The grain refinement of high-purity Mg–Al alloys occur without the superheating. Therefore it is difficult to evaluate the effect of impurities on superheating. In high-purity Mg–Al alloys, however, it seems that minute amount of C is responsible for grain refinement.抄録全体を表示PDF形式でダウンロード (2113K) -
加藤 数良, 時末 光1998 年 48 巻 8 号 p. 400-404
発行日: 1998年
公開日: 2007/03/30
ジャーナル フリー5052 aluminum alloy were friction welded using a brake type friction welding machine. Effects of the welding conditions on axial shortening behavior and tensile strength of the friction welded joints were investigated. Upset pressure such as welding conditions were determined 1.0, 1.5 and 2.0 times of friction pressure. Burn-off length increased almost lineally just after the start of friction process. Forge length increases sharply immediately after the upset process, then, forge length reaches constant value. Total loss is a good correlation with burn-off length and forge length. In case of the upset pressure being equal to friction pressure, the tensile strength of welded joints veried very widely. If upset pressure is setting higher than friction pressure, tensile strength of welded joints become higher than that of the joint with friction pressure equal to upset pressure, and amount of scatter were reduced. The maximum tensile strength of welded joints shows 92% that of the base metal.抄録全体を表示PDF形式でダウンロード (682K)
研究ノート
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古井 光明, 眞田 美智子, 佐治 重興1998 年 48 巻 8 号 p. 405-406
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 (292K)
解説：第1回軽金属学会賞
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村上 陽太郎1998 年 48 巻 8 号 p. 407-416
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 (2609K)
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