巻号一覧
50 巻, 7 号
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研究論文
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渡辺 健彦, 斎藤 威光2000 年 50 巻 7 号 p. 313-319
発行日: 2000年
公開日: 2007/03/30
ジャーナル フリーTwo kinds of alumina with 99.5% and 91.0% purity were ultrasonically bonded to aluminum. The effect of thermal conductivity, hardness and the content of SiO2 in the alumina on the strength of a joint were examined. Results obtained are summarized as follows. Under the condition of bonding pressure of 882 N and applying time of ultrasonic vibration for 1.0 s, an excellent joint is stably achieved in both alumina. The strength of the Al–91% alumina joint is higher than that of the Al–99.5% alumina joint. It seems that the effect of the thermal conductivity of the alumina on the strength of the joint is small, however, the temperature at the interface between Al and 91% alumina with lower thermal conductivity is higher by about 15°C than that between Al and 99.5% alumina. Although 99.5% alumina harder than 91% alumina tends to facilitate the breakup of Al surface oxide film and exposure of clean surface at the interface, the effect of the difference in hardness of the alumina on the strength of the joint is small.抄録全体を表示PDF形式でダウンロード (906K) -
荒川 進, 畑山 東明, 松木 一弘, 柳沢 平2000 年 50 巻 7 号 p. 320-324
発行日: 2000年
公開日: 2007/03/30
ジャーナル フリーAl2O3 and SiC particle dispersed Al–4 mass%Cu composites were prepared from mechanically alloyed (MA) and wet-mixed powders (WM). The effects of the kind, size and volume fraction of ceramic particles on aging behaviors of the composites were investigated. There were the regions with high dislocation density in the vicinity of the ceramic particles after solution treatment. The regions were due to the differential thermal expansion coefficient between ceramic particles and the matrix. In the regions, the precipitation of θ′ phases was activated and the time to the peak hardness of aging curves was shortened with increasing dislocation density. The acceleration of aging reaction was, therefore, attributed to the preferential precipitation of θ′ phases on dislocations. The amount of age-hardening was slightly dependent on the nature of ceramics, and remarkably decreased with the volume fraction of particles. In particular, the age-hardening in MA composites was low, because MA composites had many regions of very high dislocation density and grain boundaries where were preferential precipitation sites of θ phase. Present composites were mainly strengthened by the precipitation of θ′ on dislocations during aging and the apparent activation energy of aging in the composites was about 1/2 of that in IM alloy.抄録全体を表示PDF形式でダウンロード (473K) -
吉田 誠, 瀧 圭司, 福永 秀春2000 年 50 巻 7 号 p. 325-329
発行日: 2000年
公開日: 2007/03/30
ジャーナル フリーFor automobile or other machine parts, the squeeze cast aluminum alloys have been used because of its lower defects compared to the conventional die cast aluminum alloys. The effect of the hydrogen in molten aluminum alloys on the growth of the micro-porosity and mechanical properties of the squeeze cast aluminum alloys were investigated. After controlling the hydrogen content, the molten alloy was cast into a cavity with 90 MPa. In the case of hydrogen-added material, the number density of the micro-porosities increased during solid-solution treatment regardless of the type of the alloys, AC4CH, AC8A or ADC12. On the other hand, porosity was scarcely found in the degased materials. Therefore, the formation of porosity is likely to be caused by the release of the supersaturated hydrogen to the α-aluminum phase during heat treatment. As to the as-cast AC4CH material, the fracture elongation was increased with addition of hydrogen. However the tensile strength of the as-cast or T6 material was little affected by the hydrogen content.抄録全体を表示PDF形式でダウンロード (755K) -
藤井 秀紀, 菅又 信, 金子 純一, 久保田 正広2000 年 50 巻 7 号 p. 330-334
発行日: 2000年
公開日: 2007/03/30
ジャーナル フリーFor the purpose of obtaining aluminum P/M materials strengthened by solid solution of Mg and dispersion of transition metal compounds, Al-transition metal alloys with or without addition of Mg were rapidly solidified. Al–8 mass%Fe, Al–8 mass%Mn, and Al–8 mass%Mn–2 mass%Cr alloys were rapidly solidified with 0, 4 and 8 mass% Mg. Rapid solidification (RS) was performed by gas atomizing the alloy melt and subsequent splat-quenching on a rotating water-cooled copper roll under an argon atmosphere. The RS flakes were consolidated to the P/M materials by cold pressing and hot extrusion. Metallographic structures and constituent phases were studied for both RS flakes and P/M materials by optical microscope, TEM and X-ray diffraction. Mechanical properties of as-extruded P/M materials were examined by tensile test at room and elevated temperatures. Uniform dispersion of intermetallic compounds was observed in all the extruded P/M materials. Added Mg was present as the solute in all the P/M materials except for Al–Mg–Mn–Cr alloy in which solute Mg content decreased due to formation of the ternary compound Cr2Mg3Al18. The P/M materials containing Mg generally exhibited higher hardness and strength at room temperature, than those without Mg. It was considered that both solid solution of Mg and dispersion of intermetallic compounds were contributing the hardness and strength increase in the rapidly solidified Al–Mg–transition metal alloys.抄録全体を表示PDF形式でダウンロード (489K) -
崔 祺, 大堀 紘一2000 年 50 巻 7 号 p. 335-340
発行日: 2000年
公開日: 2007/03/30
ジャーナル フリーFor the purpose of grain refinement, recrystallizing behavior of differential-speed-rolled sheet of a 5083 aluminum alloy were studied by the electron back scatter pattern (EBSP) as well as optical and transmission microscopy observation, and compared with those of conventionally rolled sheet. In the same reduction, tensile strength, yield strength and hardness of differential-speed-rolled sheet are higher than those of conventionally rolled sheet. After annealing, the recrystallized grain size in differential-speed-rolled sheet is finer than that in conventionally rolled sheet. Especially, fine recrystallized grains with an average size of 2.7 μm were obtained in 91% differential-speed-rolled sheet. The fine grains might have been evolved in such a way that a lot of fine zones with high misorientation are invited by the complicated plastic deformation, peculiar to differential speed rolling with additional shear deformation, and they become continuously fine grains during subsequent annealing.抄録全体を表示PDF形式でダウンロード (1103K)
研究ノート
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金谷 輝人, 中川 惠友, 細川 智生, 谷本 雅2000 年 50 巻 7 号 p. 341-342
発行日: 2000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 (167K)
解説
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高谷 松文, 橋本 和明, 戸田 善朝2000 年 50 巻 7 号 p. 343-347
発行日: 2000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 (460K)
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