巻号一覧
49 巻, 7 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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堀江 俊男, 岩堀 弘昭, 粟野 洋司, 松井 彰1999 年 49 巻 7 号 p. 272-276
発行日: 1999年
公開日: 2007/03/30
ジャーナル フリーIn the development of magnesium alloys for high pressure die casting which have excellent high temperature strength, creep properties have been investigated with focusing on calcium addition. Creep tests were performed in the temperature range of 373–473 K and the stress range of 40–100 MPa. The creep resistance of the Mg–Zn alloy at temperature below 440 K is extremely improved with calcium addition. As the concentration of zinc increased, the creep properties tend to deteriorate. In other words, if the alloy contains less than 4 mass%Zn and more than 0.5 mass%Ca, good creep properties is shown below 440 K in the alloy systems. The fine plate precipitates consisting of several atom layers are found in the crept samples which show good creep properties. On the other hand, the coarse precipitates are observed in the samples after creep in alloys without calcium and with calcium crept above 440 K. Improvement of the creep properties by calcium addition is considered to be caused by the precipitation of fine compounds.抄録全体を表示PDF形式でダウンロード (1008K) -
井上 誠, 岩井 正雄, 鎌土 重晴, 小島 陽, 井藤 忠男, 菅間 光雄1999 年 49 巻 7 号 p. 277-281
発行日: 1999年
公開日: 2007/03/30
ジャーナル フリーIt was intended by a recycling process of professional use video camera scraps to obtain ingots that satisfy the JIS for chemical composition of AZ91D magnesium alloy. The paint finishing was removed firstly by a shot blast method and the scraps were melted. The removal decreases the generation of toxic gases during heating stage. The recovery rate of metals is remarkably improved to be more than 80% due to depression of Mg oxidation accompanied by the paint combustion. The chemical composition of recycled ingots meets the JIS and such impurities detrimental for corrosion resistance as Fe, Ni and Cr are little contained. The corrosion resistance of recycled specimens exhibits the same level as a virgin AZ91D magnesium alloy. Their tensile properties satisfy the JIS for castings, and their 0.2% proof stress is higher than that of specimens recycled from non-professional use video cameras.抄録全体を表示PDF形式でダウンロード (969K) -
鈴木 徹也, 福山 貴博, 多田 勝, 友田 陽1999 年 49 巻 7 号 p. 282-286
発行日: 1999年
公開日: 2007/03/30
ジャーナル フリーA Ti–44.1 at%Al–1.6 at%Mn alloy with unidirectionally oriented lamellar structure was made by using heavy extrusion of a mixture of titanium and Al–Mn alloy powder followed by reactive sintering under HIP. Compression tests were performed for 5 × 5 × 6 mm samples prepared in such a way that angle between the extrusion direction and compression one becomes 0°, 30°, 45°, 60° or 90°. The yield strength at 293 K is found to strongly depend on the above angle, i.e., the 0° sample shows the highest strength, the 90° sample the second while the other samples show much lower strengths. A similar anisotropic yield strength is observed for the results obtained at 1073 K although the strength of the 0° sample is much higher than that of the 90° one. Anisotropic deformation behavior observed in the present investigation is discussed in comparison with that for TiAl PST crystals reported by Fujiwara et al..抄録全体を表示PDF形式でダウンロード (1289K) -
Tadayoshi TSUKEDA, Kengo TAKEYA, Ken SAITO, Hiroshi KUBO1999 年 49 巻 7 号 p. 287-290
発行日: 1999年
公開日: 2007/03/30
ジャーナル フリーInjection molding for magnesium alloys is a new process in which metallic slurry is injected into a mold at semi-solid temperature to form net-shape products from solid feed stock in one step. The relationship between the process parameter and mechanical properties of AZ91D magnesium alloy has been investigated. It is shown that injection molding could produce parts with superior mechanical properties to those of high pressure die casting. High injection velocity refines the grain size of the surface and improves the mechanical properties.抄録全体を表示PDF形式でダウンロード (806K) -
石 雯, 小橋 眞, 長 隆郎1999 年 49 巻 7 号 p. 291-295
発行日: 1999年
公開日: 2007/03/30
ジャーナル フリーThe wettability between molten magnesium alloys and alumina substrate was investigated by the sessile drop method in order to develop the alumina short fiber reinforced magnesium composites. It is suggested that the wettability between molten magnesium and alumina substrate became better and the contact angle decreased from 89° to 80° by adding 3% zinc to the molten magnesium. However, the contact angle increased with increasing aluminum content in the molten magnesium. Based on the results of the wettability measurements, the alumina short fiber reinforced magnesium matrix composites was fabricated by the spontaneous infiltration of molten magnesium into the alumina fiber preform. The compressive tests indicated that the compressive strength appears to be affected by the fabrication process. The compressive strength of the Mg–8%Al alloy reinforced by alumina short fiber was 2 times higher than that of the monolithic alloy at room temperature.抄録全体を表示PDF形式でダウンロード (921K) -
金 英泰, 池田 圭介, 村上 糺1999 年 49 巻 7 号 p. 296-301
発行日: 1999年
公開日: 2007/03/30
ジャーナル フリーWhile the porthole die extrusion has been widely used in manufacturing hollow products, die manufacturing including die designing has been still dependent on the expert's skill and trial and error practice. Although detailed understanding of die pressure in extrusion is essential to systematic die designing and also leads to more correct results of finite element analysis, the experimental research for die pressure in porthole die extrusion has hardly been found. In this study, in order to investigate the distribution of die pressure in porthole die extrusion, pressure sensor which has lots of concentric serration was used. Pressure sensors were placed on the faces of dies (core and cap), before extrusion starts. The die pressure was examined at two different extrusion stages: the one was just after division process was completed and the other was during steady state. Just after division process was completed, the highest pressure area on the core existed in the vicinity of the porthole near the center. In steady state, pressure gradient was very large in the area between the porthole and die edge, and the pressure around the central part was lower on the core. Besides, the pressure decreased from outside to die exit on cap.抄録全体を表示PDF形式でダウンロード (1284K)
解説
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今村 次男1999 年 49 巻 7 号 p. 302-309
発行日: 1999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 (1697K)
連載講座
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寺田 貢, 大場 勇治郎1999 年 49 巻 7 号 p. 310-314
発行日: 1999/07/30
公開日: 2021/06/30
ジャーナル フリーPDF形式でダウンロード (33023K)
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