巻号一覧
47 巻, 12 号
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研究論文
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兵庫 靖憲, 桃崎 博人, 当摩 建1997 年 47 巻 12 号 p. 655-660
発行日: 1997年
公開日: 2007/03/30
ジャーナル フリーThe tube-header joint in heat exchangers for automobiles requires to fill the clearance perfectly. Effects of factors such as clearance geometry, Si content in Al–Si braze alloy and brazing temperature etc. were examined in the fluoride flux brazing by clearance fillability test. Clearance geometry, especially clearance width was the most dominant for fillability. In the same clearance width, fillability increased with higher Si content in braze alloy and higher brazing temperature. Further, excellent fillability was obtained even in lower brazing temperature at 580°G in the Al–Si braze alloys containg Zn or Cu. The results were discussed in terms of flowability of the filler, that is, the fraction of the liquid at the temperature.抄録全体を表示PDF形式でダウンロード (1012K) -
谷畑 弘之, 松田 健二, 池野 進1997 年 47 巻 12 号 p. 661-666
発行日: 1997年
公開日: 2007/03/30
ジャーナル フリーThe effect of cooling rate on the occurrence of Al–Fe–Si intermetallic compound phases in 6063 aluminum alloy was investigated in the as-cast state using X-ray diffraction and transmission electron microscopy (TEM). The four alloys containing 0.1 to 0.5 mass%Fe were melted and then cooled at three cooling rates ranging from 0.06 to 5 K/s, and the Al–Fe–Si compound particles were extracted from the alloy ingots using the thermal phenol method. With increasing cooling rate, the amount of a skeleton-shaped α phase increased irrespective of iron content and that of the β phase decreased. When the iron content increased over 0.2%, the amount of the β phase decreased at the intermediate cooling rate (5 K/s). When the iron content decreased from 0.2 to 0.1%, the amount of the β phase also decreased and the α' phase co-existed. As a result, at a typical Fe content, i.e., 0.2%Fe, in commercial 6063 alloys, the β phase was most frequently formed in comparison with other Fe content, and became the main phase even at the intermediate cooling rate (5 K/s) which was roughly equal to that for the commercial ingots.抄録全体を表示PDF形式でダウンロード (1294K) -
加藤 鋭次, 野村 宏之, 大城 直人1997 年 47 巻 12 号 p. 667-671
発行日: 1997年
公開日: 2007/03/30
ジャーナル フリーA series of thermal analysis and microstructural observation were carried out in order to clarify the effect of the phosphorus as a site of heterogeneous nucleation during the Al–Si hypoeutectic solidification. The solidification time become shorter by the addition of phosphorus, than that of without phosphorus. Liquidus and eutectic temperature become low with the increase of cooling rate, but the magunitude of the decrease in eutectic temperature is large in the case of phosphorus alloys free. The microstructure of eutectic silicon depends on the level of phosphorus content. The coarse needle-like silicon particles are nucleated on the AlP. The phosphorus rejected during the solidification of primary α aluminum therefore, the nucleus formation for eutectic silicon is just before eutectic solidification. If phosphorus is contained in the molten metal, the quantity of the primary crystal of α-dendrite increases, whereas it's length is short.抄録全体を表示PDF形式でダウンロード (963K) -
平田 幸四郎, 福池 渉, Rachmat Suhradi RUDI, 鎌士 重晴, 小島 陽1997 年 47 巻 12 号 p. 672-678
発行日: 1997年
公開日: 2007/03/30
ジャーナル フリーA semi-solid press-forming process was applied to Mg–4~8%Al, Mg–4~8%Al–2%Ca and Mg–4~8%Al–l%Si– 0.5%Ca alloys for a purpose of toughness improvement. Effects of heat treatment were investigated on tensile properties and microstructure of the semi-solid formings. Fine globular particles of the α-phace are distributed uniformely together with the fine eutectic constituent in the semi-solid formings made from 15% strained materials. The grain size of the α-phase particles in as-formed specimens decreases with increasing aluminum and calcium contents. A network of intermetallic compound, Mg17Al12 crystallized along grain boundaries in the Mg–Al binary and Mg–Al–1%Si–0.5% Ca alloys, breaks up with decreasing aluminum content, resulting in increases both of tensile strength and of elongation. The Mg17Al12 compounds disappear after the T4–treatment in the all investigated alloys, while the shape of Al2Ca compounds becomes globular after the T4–treatment of Mg–Al–2%Ca alloys alone. The microstructural changes clearly improve tensile strength and elongation. The age hardning by precipitation of Mg17Al12 phase occurs by T6–treatment in the Mg–Al binary and Mg–Al–1%Si–0.5%Ca alloys with aluminum content more than 6%, and in the Mg– Al–2%Ca alloys with aluminum larger than 8%. The aged specimens exhibit higher tensile strength and 0.2% proof stress than as-formed spesimens.抄録全体を表示PDF形式でダウンロード (2666K) -
田村 洋介, 河野 紀雄, 茂木 徹一, 佐藤 英一郎1997 年 47 巻 12 号 p. 679-684
発行日: 1997年
公開日: 2007/03/30
ジャーナル フリーEffects of Zr addition via Mg–Zr master alloy on the grain refinment in the magnesium ingots was investigated in view of grain size and concentration of soluble Zr. Specimens were prepared by adding Zr up to 2.0 mass% at temperatures 993 K, 1033 K and 1073 K, and examined using optical microscope (OM), scanning electron microscope (SEM) and electron-probe micro analyzer (EPMA). It was found that concentration of soluble Zr was almost independent of the melt temperature between 993 K to 1073 K, where the master alloy was introduced. Grain size was decreased with increasing soluble Zr content exponentially and, at 0.4mass%Zr or more, grain size become constant at about 30 μm (permanent molded castings) and 70 μm (shell molded castings), even if the peritectic composition, 0.6 mass%Zr was not reached. SEM and EPMA observation revealed substructure including Zr-enriched cored area, which is formed characteristically; i.e., in the most cases, metallic Zr particle is located at the center of the core, surrounded by several rings, each of which is made up by Zr enriched Mg solid solution. Such experimental results suggest that some undis-solved Zr particles play an important role in the nucleation of the observed ring structure and this grain refinement pro-ceses is based on non-equilibrium solidification.抄録全体を表示PDF形式でダウンロード (1063K) -
鈴木 徹也, 高野 忠冨, 鈴木 勲, 友田 陽1997 年 47 巻 12 号 p. 685-690
発行日: 1997年
公開日: 2007/03/30
ジャーナル フリーTitanium alloys cannot be used for structural materials at a temperature over 873 K because of their poor oxidation resistance. In this study, the Al3Ti layer was formed on the surface of the titanium plates by aluminizing on purpose to improve the oxidation resistance. The layers of intermediate phases of TiAl2, TiAl and Ti3Al and their uneven interface were found in a specimen which was heat treated at 1173 K. They are effective for relieving the thermal stress between the outside Al3Ti layer and the inside titanium plate. The aluminum and chromium combined diffusion treatment is effective to inhibit the formation of crack within the Al3Ti layer and to suppress the growth of intermediate phase which is believed to deteriorate the oxidation resistance.抄録全体を表示PDF形式でダウンロード (1446K) -
箕田 正, 吉田 英雄1997 年 47 巻 12 号 p. 691-695
発行日: 1997年
公開日: 2007/03/30
ジャーナル フリーThe influence of ingot homogenization on the microstructure of 3003 aluminum alloy extrusion was investigated. When precipitates in the ingot were almost smaller than 0.1 μm size and precipitated with high density, extrusion became fiber structure. But the thermal stability of fiber structure was depended on the form of constituent particles in the ingot. When constituent particles covered the cell boundaries, extrusions became fully fiber structure. On the other hand, when constituent particles transformed into necklace structure and became smaller during homogenization, the surface of extrusions recrystallized and became abnormal grain growth structure. When precipitates in the ingot were almost bigger than 0.1 μm size, precipitated uniformly and matrix had much solutions, extrusions recrystallized easily so that extrusions became fine recrystallized structure. When precipitates bigger than 0.1 μm size were less and they did not disperse uniformly, extrusions became bigger recrystallized structure.抄録全体を表示PDF形式でダウンロード (1449K)
研究ノート
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金谷 輝人1997 年 47 巻 12 号 p. 696-697
発行日: 1997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 (353K) -
金谷 輝人, 細川 智生, 谷本 雅, 榊原 精, 西田 典秀1997 年 47 巻 12 号 p. 698-699
発行日: 1997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 (253K) -
杜 浩, 浅沼 博1997 年 47 巻 12 号 p. 700-701
発行日: 1997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 (267K)
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