巻号一覧
50 巻, 3 号
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研究論文
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間渕 博, 津田 大, 森井 賢二2000 年 50 巻 3 号 p. 99-104
発行日: 2000年
公開日: 2007/03/30
ジャーナル フリーButton ingots of Al–Ti–Cr alloys with the L12–structure were prepared by arc-melting to investigate the effects of composition on the material properties. The formation of the porosity was closely associated with the diffusion-solutionized second phase (Al17Cr9). However, no residual porosity was observed in higher chromium L12–type alloys; Al–25Ti–14Cr alloy. The Vickers hardness and 0.1% bend proof strength were nearly independent on the chromium contents, although the higher titanium alloys had slightly larger values. These observations suggest that the hardness and strength of the L12 phase are substantially independent on the composition of the macro-alloying element (chromium) for the ternary L12 phase, but are dependent on an off-stoichiometry for the titanium composition. The L12–type alloys showed some bend ductility at ambient temperature, which increases to 0.8% (plastic bend strain) with increasing chromium content, when porosity is reduced. It was found that the L12–type intermetallics in the Al–Ti–Cr system have a good linear expansion coefficient, and an excellent oxidation resistance.抄録全体を表示PDF形式でダウンロード (532K) -
後藤 卓史, 安藤 新二, 頓田 英機2000 年 50 巻 3 号 p. 105-108
発行日: 2000年
公開日: 2007/03/30
ジャーナル フリーTo clarify the activity of the secondary pyramidal slip system in magnesium and titanium, core structures of (c+a) edge and (c+a) screw dislocations have been investigated by molecular dynamics method. The Lennard-Jones type and Finnis-Sinclair type potentials were employed. Stabled core structures were obtained in various temperature ranges. The (c+a) edge dislocation in magnesium has two kinds of core structures at 0 K; one is perfect dislocation (Type–A) and the other two 1/2 (c+a) partial dislocations (Type–B) . The type–A core structure expands to the basal plane with increasing temperature, while the type–B core is stable at higher temperatures. In the case of titanium, (c+a) edge-dislocation shows perfect dislocation independent of initial core structure and temperature. Furthermore, it never moves by applying strain. This behavior is different from the previous result of magnesium that the Type–A core changes to two partial dislocations (Type–B) and moves on the (1122) slip plane by applying strain, and the Type–B core slips without a change of structures. In the case of the (c+a) screw-dislocation, the core structures of titanium and magnesium expand on two first order pyramidal planes at 0 K, and they change to the structure expanded on a secondary pyramidal plane with increasing temperature. The activities of the secondary pyramidal slip system in titanium and magnesium can be explained from the difference of (c+a) edge dislocation core structures.抄録全体を表示PDF形式でダウンロード (466K) -
梅原 博行, 高谷 松文, 小島 陽2000 年 50 巻 3 号 p. 109-115
発行日: 2000年
公開日: 2007/03/30
ジャーナル フリーConversion coatings for magnesium have traditionally been based on immersion treatment in the solution containing hexavalent chromium compounds. The excellent performance of these coatings as paint bases has been established in a broad range of application. However, the replacable surface treatment has been strongly emphasized by present environmental needs to eliminate hexavalent chromium. The development of a chemical conversion coatings in permanganate bath on magnesium alloys have been studied using mass gain measurements, measurements of corrosion potential, X-ray diffraction, X-ray photoelectron spectroscopy, glow discharge spectroscopy and microscopic examination. Chemical conversion coatings obtained from HF addition in bath consisted of the film that was composed mainly of manganese oxides and magnesium fluoride. It was found that these films formed amorphous composite coating. Corrosion resistances of permanganate chemical conversion coatings were comparable with that for chromating.抄録全体を表示PDF形式でダウンロード (609K) -
黒木 康徳, 田中 徹, 里 達雄, 神尾 彰彦2000 年 50 巻 3 号 p. 116-120
発行日: 2000年
公開日: 2007/03/30
ジャーナル フリーIn order to clarify the effect of casting microstructures on fatigue properties of Al–9%Si–1.6%Cu–O.55%Mg alloy castings, the fatigue properties of non-degassing castings, degassed castings and HIPed castings with different size of microstructures were examined. Elongation and fatigue property increase remarkably with decreasing of gas quantity in melt. Gas porosity affect not only crack origins but crack growth paths. In HIPed castings, Fe compounds, which have needle-like shape affect as crack origins. However, in the castings with finer microstructure, decreasing with size and aspect ratio of compounds, capability for crack origin is reduced, and the scatter of fatigue strength occurs by crystal growth direction of Fe compounds. In castings with larger microstructures, Fe compounds with larger size and aspect ratio decrease fatigue property significantly in any growth direction.抄録全体を表示PDF形式でダウンロード (582K)
解説：小山田記念賞
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佐藤 正和, 斉藤 政昭, 安永 晋拓, 木山 啓, 井手籠 隆2000 年 50 巻 3 号 p. 121-127
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 (713K)
連載講座
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水野 薫2000 年 50 巻 3 号 p. 128-134
発行日: 2000/03/30
公開日: 2021/06/30
ジャーナル フリーPDF形式でダウンロード (1854K)
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