巻号一覧
37 巻, 12 号
選択された号の論文の9件中1～9を表示しています
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西川 工1987 年 37 巻 12 号 p. 781-783
発行日: 1987/12/30
公開日: 2008/07/23
ジャーナル フリーPDF形式でダウンロード (403K) -
鎌土 重晴, 佃 誠, 徳富 一郎, 広瀬 喜興1987 年 37 巻 12 号 p. 784-791
発行日: 1987/12/30
公開日: 2008/07/23
ジャーナル フリーThe alloys were unidirectionally solidified and T5 treated at 215°C for 5h. The alloys have columnar dendrites at Zr content nil, petaline equiaxed grains at Zr 0.12 to 0.42% and circular or hexagonal equiaxed grains at Zr above 0.6%. Grain size exponentially decreases and eutectic compounds increase with increasing cooling rate in the liquid VLC and Zr content resulting in rises of tensile properties and Brinell hardness. Proof stress, tensile strength and hardness are improved by T5 treatment. The maximum load and crack initiation energy in instrumented impact testing on the alloys both cast and T5 treated containing Zr more than 0.12% show a tendency against VLC and Zr content similar to that of tensile properties, but crack propagation energy shows a reverse one. Total absorbed energy of the Zr free alloys decreases, but that of the alloys containing Zr more than 0.12% increases with increasing VLC. The addition of Zr increases the maximum load, but decreases other impact properties.抄録全体を表示PDF形式でダウンロード (1670K) -
鎌土 重晴, 佃 誠, 徳富 一郎, 広瀬 喜興1987 年 37 巻 12 号 p. 792-799
発行日: 1987/12/30
公開日: 2008/07/23
ジャーナル フリーMg-3.2%Zn-0.7%Zr-X%RE (X = 0, 2.6, 4.0, 4.6 and 7.5) alloys were unidirectionally solidified and T5 treated at 215°C for 5h. As the cooling rate in the liquid phase is accelerated and RE content is increased, equiaxed grains are refined, Zn in the matrix is diluted, and the amount of Mg-RE-Zn eutectic compounds is increased. The tensile strength, elongation and impact properties lower and proof stress and Brinell hardness rise in accordance with RE content. The strength of the alloys T5-treated rises with an increase in Zn in the solidified matrix. Brinell hardness, maximum load, crack initiation energy and total absorbed energy are improved as the cooling rate in the liquid state is accelerated.抄録全体を表示PDF形式でダウンロード (1660K) -
西村 章, 川野 豊1987 年 37 巻 12 号 p. 800-806
発行日: 1987/12/30
公開日: 2008/07/23
ジャーナル フリーAlternating electromagnetic stirring at 2 Hz was applied to solidifying aluminum with and without Ti, and Al-Si, Al-Cu, Al-Ni and Al-Zn alloys. The etching figure of interdendritic compounds consisting of impurities or alloying elements forms continuous networks by stirring solidifying aluminum and Al-1%Cu, Al-5%Si and Al-3%Si alloys. Secondary dendrite arm spacings in Al-Si, Al-Cu and Al-Ni alloys are extended by stirring. In Al-9%Cu, Al-7%Si and Al-4%Ni alloys, primary dendrites easily aggregate and divorced eutectic structure is formed by stirring. A pronounced tendency toward segregated structures such as aggregation of primary Si particles and appearance of dendrites and partially fine eutectic structures are observed in stirred Al-19%Si alloy.抄録全体を表示PDF形式でダウンロード (2374K) -
小林 賢三, 清水 健一, 津田 義弘1987 年 37 巻 12 号 p. 807-810
発行日: 1987/12/30
公開日: 2008/07/23
ジャーナル フリーThe structure of porous anodic films formed on Al-0.5%Si alloys were examined by transmission electron microscopy of ultramicrotomed sections with special attention to the behavior of Si precipitates during anodic oxidation. Si precipitates are incorporated into the porous anodic film growing over aluminum matrix surrounding the precipitates. Incorporation of Si precipitates proceeds in such a manner that the pores in the porous film growing over the aluminum matrix branch to undercut aluminum beneath the precipitates. Some of the branched pores develop even in the direction parallel to the metal surface.抄録全体を表示PDF形式でダウンロード (1505K) -
兼松 秀行, 井上 哲雄, 興戸 正純, 沖 猛雄1987 年 37 巻 12 号 p. 811-815
発行日: 1987/12/30
公開日: 2008/07/23
ジャーナル フリーAl-Zn-Mg alloys two stage aged, solution treated and peak aged (one stage aging) and over aged (one stage aging) were corroded in NaCl solution. Inner parts of grains in the two stage aged, peak aged and over aged alloys dissolve and grain boundaries remain undissolved. The peak aged alloy undissolves at grain boundaries to a greater extent than the over aged alloy. Both inner parts and grain boundaries in the solution treated alloy dissolve. The capacitance calculated from interfacial impedance of grain boundaries is usually higher than that of inner parts of grains. The difference of capacitance between inner parts and grain boudaries is governed by heat treatment. A certain intermediate capacitance can be taken as a critical value for insolubility. Insoluble grain boundaries have a greater capacitance than the critical value. It is suggested from the relationship between corrosion behavior and interfacial impedance that oxide films play an important role in corrosion.抄録全体を表示PDF形式でダウンロード (1275K) -
小林 俊郎, 新家 光雄, 出川 公雄1987 年 37 巻 12 号 p. 816-823
発行日: 1987/12/30
公開日: 2008/07/23
ジャーナル フリーAl-2.7%Li-1.2%Cu-0.8%Mg-0.1%Zr wrought alloys are heat treated to improve their impact toughness at lower temperatures, although a number of laminated cracks form in the vertical direction to the fracture surface. Low melting point elements, K and Na, are found on the fractured surface by Auger spectroscopy. The maximum local temperature rise at crack tips under dynamic loading is calculated to be 90 K. The temperature modified from this local temperature rise is equivalent to the melting point of the metal phase having lowest melting point and the lowest temperature for starting impact toughness weakening. The low melting point metal phase probably causes liquid embrittlement at grain boundaries.抄録全体を表示PDF形式でダウンロード (1518K) -
小林 俊郎, 新家 光雄, 池田 浩一1987 年 37 巻 12 号 p. 824-830
発行日: 1987/12/30
公開日: 2008/07/23
ジャーナル フリーPermanent mold castings of high purity binary Al-Si alloys (Si: 3, 7, 12 and 20%) were tested. The fatigue crack propagation in as-cast alloys in the Paris regime is seriously influenced by Si concentration less than eutectic composition. Al-20%Si alloy is less stable in fatigue crack propagation than the other alloys. Solution treated high Si alloys show slower rates of fatigue crack propagation than as-cast alloys. The fact depends on strengthening of the matrix, forming of eutectic Si particles into spheres and on increase in crack closure. The resistance to fatigue crack initiation is improved by high content of Si in as-cast alloys and by solution treating.抄録全体を表示PDF形式でダウンロード (975K) -
星野 重夫1987 年 37 巻 12 号 p. 831-837
発行日: 1987/12/30
公開日: 2008/07/23
ジャーナル フリーPDF形式でダウンロード (886K)
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