巻号一覧
44 巻, 4 号
選択された号の論文の11件中1～11を表示しています
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〓 福賜, 山口 克彦, 高倉 章雄, 今谷 勝次1994 年 44 巻 4 号 p. 197-203
発行日: 1994/04/30
公開日: 2008/10/30
ジャーナル フリーUpsetting tests of sintered aluminum powder preforms with different initial relative densities are carried out at various temperatures and strain rates to examine the effects of these factors on the flow stress and the density change. A computer controlled high speed press is used to keep a constant strain rate throughout an upsetting process, and lubrication is repeated at every 0.1 axial strain to avoid both the friction between tools and specimen and the temperature rise due to plastic deformation. The effects of temperature and strain rate on the material constants N, a and b which are included in the Oyane and Shima plasticity theory of porous materials are also discussed. The flow stress in the practical forming condition in which the temperature of specimen increases with increasing strain is considered based on the stressstrain curves at a constant temperature. Experimental results show that the density change of sintered material hardly depends on the temperature and strain rate, but that the flow stress increases with increasing strain rate and decreases with increasing temperature.抄録全体を表示PDF形式でダウンロード (783K) -
大崎 修平, 小林 一徳, 田中 浩毅, 辻 美紘1994 年 44 巻 4 号 p. 204-209
発行日: 1994/04/30
公開日: 2008/10/30
ジャーナル フリーSCC susceptibility of Al-Li alloys 2090 and 2091 was investigated using C-ring specimens machined from the thick plate in S-L direction. The SCC susceptibility depends on the temper conditions, the underaged (UA), peak-aged (PA) and overaged (OA), increasing in the order of OA>PA>UA for alloy 2090, and UA>PA>OA for alloy 2091. Alloy 2090 has higher resistance to SCC initiation than alloy 2091. Under constant immersion in 3.5%NaCl solution, the SCC susceptibility is low, while addition of Li2CO3 promotes SCC. SCC of these Al-Li alloys is attributed to the local anodic dissolution along grain boundaries which depends on the passivation phenomena.抄録全体を表示PDF形式でダウンロード (2008K) -
朝比奈 敏勝, 大久保 通則, 時末 光1994 年 44 巻 4 号 p. 210-215
発行日: 1994/04/30
公開日: 2008/10/30
ジャーナル フリーAZ80 magnesium alloy plates with 5, 10 and 15mm thickness were butt welded using a high voltage electron beam welder with a capacity of 6kW (150kV×40mA). The optimization of welding conditions and microstructural observation have been carried out together with the mechanical tests on the electron beam welded joints, with the special reference to the effect of specimen plate thickness. Independent of the plate thickness, the welded joints were almost free from welding defects and showed good bead appearance under appropriate welding conditions. The arcing phenomena tended to appear with increasing plate thickness and decreasing active beam parameter. Both optimum beam current and welding speed were smaller than those for electron beam welded joints of aluminum alloys, while active beam parameter remained constant. For the plate thickness of 5 and 15mm, the penetration width was constant throughout the plate thickness. For the plate thickness of 10mm, however, the penetration width at top surface was different from that at bottom surface, resulting in a so-called wedge type bond zone. Regardless of the plate thickness, microstructure in the fusion zone was remarkably fine, although the grain boundary could not unambiguously detected. Hardness in the fusion zone was in good agreement with that of base metal. Both tensile strength and ductility of the welded joints were identical with those of base metal independent of the plate thickness. In tension tests of welded joints, fracture occurred either in heat affected zone or in base metal. The specimens notched into the center of fusion zone showed higher impact values than those of the base metal.抄録全体を表示PDF形式でダウンロード (1443K) -
古閑 正明, 鷹合 徹也, 中山 栄浩, 大西 脩嗣, 飯塚 康夫, 松村 吉修, 三石 芳久1994 年 44 巻 4 号 p. 216-221
発行日: 1994/04/30
公開日: 2008/10/30
ジャーナル フリーThe cooling rate in a range of 3.3 to 12.1K/s was measured in 3 to 15mm thick castings. The tensile properties are improved with higher cooling rate. The marked effect of cooling rate on the dendrite structure is clearly observed, and the linear relation between the dendrite arm spacing and the cooling rate is found. The increased cooling rate refines the size of eutectic silicon particles but it dose not influence the spheroidization of these particles. The concentration of magnesium in the matrix increases especially with higher cooling rate in the state of solution treatment. The improvement of tensile properties are attained by the increasing of precipitates due to higher magnesium concentration in the matrix and of refined eutectic silicon particles.抄録全体を表示PDF形式でダウンロード (898K) -
熊井 真次, 胡 健群, 石倉 誠, 肥後 矢吉, 布村 成具1994 年 44 巻 4 号 p. 222-228
発行日: 1994/04/30
公開日: 2008/10/30
ジャーナル フリーTensile properties have been investigated in SiC particulate-reinforced cast A356 aluminum alloy composites with systematically controlled solidification structure and aging condition. Tests were also performed for an unreinforced matrix alloy for comparison. The composite exhibited increased elastic modulus, 0.1% proof stress and reduced elongation compared to the matrix alloy. Refinement of the solidification structure provided comparable improvement in proof stress, UTS and elongation values in both the composite and the matrix alloy. The Hall-Petch type relation was found between the proof stress and the dendrite arm spacing. The aging time dependence of the tensile properties of the composite was comparable to that of the matrix alloy. Consequently, each effect of particle reinforcements, solidification structure and age-hardening was successfully extracted from the overall yield stress increment of the composite.抄録全体を表示PDF形式でダウンロード (1482K) -
堀 茂徳, 浜野 勇, 長畑 一拓, 田村 健, 安倍 睦, 田井 英男1994 年 44 巻 4 号 p. 229-233
発行日: 1994/04/30
公開日: 2008/10/30
ジャーナル フリーAging characteristics of Mg-9mass%Al alloy have been investigated by means of hardness measurement and microstructure observation with optical and electron microscopy. Hardness increased by about HV30 with aging time at temperatures between 403-473K. The hardness increase was found to be caused by the continuous and discontinuous precipitation. The TTT diagram for the phase decomposition was determined from the hardness curves, the nose temperature being 523K. The initiation and growth of the grain boundary reaction occur in competition with well-advanced continuous precipitation process. The apparent activation energy for grain boundary reaction is also described.抄録全体を表示PDF形式でダウンロード (1563K) -
福富 洋志, 鈴木 徹也, 稲積 俊昌, 上城 太一1994 年 44 巻 4 号 p. 234-239
発行日: 1994/04/30
公開日: 2008/10/30
ジャーナル フリーUniaxial compression tests were conducted at temperatures and strain rates ranging from 1173 to 1473K and 1.0 × 10-4 to 5.0 × 10-3 s-1, respectively. Examination of the aspect ratios as well as the sizes of grains after deformation reveals that the predominant process of dynamic restoration varies depending on the flow stress. Dynamic recovery is dominant at the deformations under lower and higher stresses while dynamic recrystallization occurs under the intermediate stresses. Three kinds of preferred orientations, namely (110), (110) + (111) and (111) fiber textures, develop corresponding to the difference in the dynamic restoration process.抄録全体を表示PDF形式でダウンロード (952K) -
阿部 佑二, 吉田 正勝1994 年 44 巻 4 号 p. 240-245
発行日: 1994/04/30
公開日: 2008/10/30
ジャーナル フリーThe tensile tests of 5182 alloys had been carried out at the warm temperature. The tensile and yield strength decrease, and the local elongation increased with higher temperature. But the elongation to the yield strength, the degree of serration and n-values decrease. The ratio (H/L0) of drawn depth (H) to the square punch side length (L0) are reached to 1.0 in the warm forming that is the limit of die-set, whereas that is reached to 0.27 in the room temperature forming. The optimum temperature of punches, die and blank-holder are shown by the analysis of drawn depth ratios and fracture types. The maximum strain of double square sinks are enormous. The major strain (ε1) is 2.33, and this strain is about equal to deformation in the superplasticity.抄録全体を表示PDF形式でダウンロード (1386K) -
伊東 章郎, 岩井 克夫, 長良 敏夫, 宮木 美光, 藤本 日出夫, 瀧川 淳1994 年 44 巻 4 号 p. 246-252
発行日: 1994/04/30
公開日: 2008/10/30
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植原 寅蔵1994 年 44 巻 4 号 p. 253-254
発行日: 1994/04/30
公開日: 2008/10/30
ジャーナル フリーPDF形式でダウンロード (204K) -
諸住 正太郎1994 年 44 巻 4 号 p. 255-256
発行日: 1994/04/30
公開日: 2008/10/30
ジャーナル フリーPDF形式でダウンロード (244K)
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