巻号一覧
57 巻, 1 号
選択された号の論文の6件中1～6を表示しています
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研究論文
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松居 正夫, 矢野 治久, 井上 孝司, 河部 昭雄2007 年 57 巻 1 号 p. 2-5
発行日: 2007年
公開日: 2007/02/28
ジャーナル フリーPress forming test apparatus to be able to change from room temperature to 673 K was developed for evaluating characteristics of warm press formability in magnesium alloy sheets. By using of this apparatus, a cylindrical cupping test for deep drawability, a bore expanding test with flat punch for stretch-flanging formability, and a hat-shape bending test for shape fixability have been carried out on two kinds of AZ31 magnesium alloy sheets (A material and B material). As a result, limiting drawing ratio (LDR) becomes 2.5 at the time of forming temperature 433 K, and forming height in the cylindrical cupping test is higher for larger punch shoulder radius. In the stretch-flanging formability, bore expanding ratio can get maximum value at 473 K and is constant at more than 473 K. Shape fixability is improved as the forming temperature is raised, and at 573 K, spring back is reduced to almost zero. A characteristic of warm press forming varies with a production condition of materials, and has strong correlation with mechanical properties at forming temperature.抄録全体を表示PDF形式でダウンロード (604K) -
田口 広一, 根本 尚生, 木原 幸一郎, 磯野 宏秋, 杉林 俊雄2007 年 57 巻 1 号 p. 6-11
発行日: 2007年
公開日: 2007/02/28
ジャーナル フリーAn impact test equipment was developed. This equipment is able to produce comparatively low load rate of impact. The impact strength of the acrylic adhesive under low temperature was measured using the developed impact test equipment. By using aluminum alloy as adherend, the equipment can measure the impact strength of acrylic adhesive. The tensile strength of the adhesive under various load rate and low temperature were measured. Conventional equipments were also used for these tests. Relations between the load rate, the test temperature and the tensile strength of adhesive were investigated. As an experimental result, at any case of load rate the tensile strength of the acrylic adhesive increased once with temperature decrease. However, when the temperature decreased lower than a specific value, the strength of the adhesive decreased. The temperature that the strength of the adhesive becomes maximum rises with the increase of the load rate. The change of strength of the acrylic adhesive is influenced by the viscosity of the adhesive itself.抄録全体を表示PDF形式でダウンロード (691K) -
菅野 能昌, 谷口 尚司, 嶋崎 真一, 吉川 昇2007 年 57 巻 1 号 p. 12-18
発行日: 2007年
公開日: 2007/02/28
ジャーナル フリーIn our previous study, aluminum matrix composites partly reinforced by SiC particles were fabricated by the imposition of a high frequency magnetic field to molten aluminum suspending SiC particles. The thickness of particle-accumulated layer (PAL) was almost the same as the skin depth that depends on the frequency of the magnetic field. In the present study, a 3 kHz magnetic field is applied to realize thicker PAL. Although a 4.71 mm PAL is expected at 3 kHz, PAL is not formed because of a strong electromagnetic flow. Intermittent imposition of magnetic field is tested to increase PAL, which seems effective to reduce the electromagnetic flow. A 4 mm PAL with dense particle packing is realized by an intermittent magnetic field composed of 1 s imposition and 1 s pausing. Numerical calculation is performed to understand the behavior of metal flow with the intermittent magnetic field. It is found that 0.5 s is required for the development of metal flow. As the relaxation time of a single SiC particle in molten aluminum is far less than 0.5 s, PAL can be formed before the metal flow develops.抄録全体を表示PDF形式でダウンロード (1794K) -
安藤 誠, 妹尾 政臣, 菅野 幹宏2007 年 57 巻 1 号 p. 19-24
発行日: 2007年
公開日: 2007/02/28
ジャーナル フリーCommercially available A7075 and A7050 alloys showed environmental degradation in ductility accompanied by intergranular fracture when tested at a slow strain rate of 10−7/s, compared to the ductility obtained by testing at a conventional strain rate of 10−4/s in a laboratory air. The degradation or embrittlement became severe with the increase in relative humidity of the testing environment. In every humidity, the embrittlement of the A7050 alloy was more serious than that of the A7075 alloy. Laboratory-made X7075 alloy which had the same amount of major solutes with the A7075 alloy but containing Zr in place of Cr revealed that additive Zr brought about more serious environmental degradation compared to the Cr-bearing alloy. The reasons for these phenomena were discussed in detail.抄録全体を表示PDF形式でダウンロード (1522K) -
山田 浩之, 堀川 敬太郎, 小林 秀敏2007 年 57 巻 1 号 p. 25-29
発行日: 2007年
公開日: 2007/02/28
ジャーナル フリーAn impact tensile test was performed by means of the split-Hopkinson bar method to clarify the influence of strain rate on high temperature embrittlement in Al–5%Mg alloys containing traces of sodium. When the specimen was tested at a strain rate of 500 s−1, the hot ductility of the Al–5%Mg–2 ppm Na alloy decreased with increasing testing temperature, and the recovery of the ductility above 400°C was not identified. As a result of the impact test, the temperature lowering the hot ductility shifted to higher temperature in comparison with the quasi static test. Intergranular fracture was observed around 300°C in both the quasi static test and the impact test. However, area fraction of the intergranular fracture decreased in the impact test around 300°C. Observation of intergranular fracture surfaces revealed that a number of intergranular dimples were observed at grain boundary after the quasi static test, while the ledge patterns were observed at grain boundary after the impact test. It was also clarified that the high temperature embrittlement was suppressed by 200 ppm of bismuth addition below 400°C even when the specimen was deformed at high strain rate of 500 s−1.抄録全体を表示PDF形式でダウンロード (1240K)
解説
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土井 稔, 香月 太, 熊谷 洋志, 高木 誠2007 年 57 巻 1 号 p. 30-36
発行日: 2007年
公開日: 2007/04/30
ジャーナル フリーPDF形式でダウンロード (4183K)
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