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荒城 昌弘, 松田 健二, 李 昇原, 土屋 大樹, 池野 進2019 年 69 巻 7 号 p. 327-331
発行日: 2019/07/30
公開日: 2019/08/30
ジャーナル フリーThe effect of extrusion conditions on recrystallization texture and preferential orientation formation of A6063 aluminum alloy extruded material was evaluated by electron back scattered diffraction (EBSD) technique and the extrusion simulation. Samples were prepared by different extrusion conditions as follows; extrusion temperature at 773 and at 813 K, the extrusion ram speed to 3 and 10 mm/s, and the extrusion ratio for 28.9, 34.7 and 66.6. The recrystallized texture of the extruded material was mainly composed of Cube orientation and Goss orientation in which 〈100〉 was oriented parallel to the extrusion direction. The Brass, S, {112} 〈110〉 orientation in which the 〈111〉 orientation was oriented in the extrusion transverse line direction was the preferential orientation on the surface. The distribution of texture corresponded to the distribution state of extrusion shear stress found by simulation. The magnitude of the shear stress also changed by changing the extrusion conditions, and the presence ratio of the Brass, S, {112} 〈110〉 orientation of the surface was changed, but the major orientation did not change.
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坂岡 優也, 倉本 繁, 川畑 博之, 車田 亮2019 年 69 巻 7 号 p. 332-338
発行日: 2019/07/30
公開日: 2019/08/30
ジャーナル フリーMagnesium has the lowest density among the engineering metallic materials and significant weight reduction can be achieved if magnesium alloys are used in automobiles, trains, airplanes, etc. However, they have some practical limitations in mechanical properties and corrosion resistance compared with other metallic materials. Generally, grain refinement is an effective way for enhancing the strength of metallic materials, and it has been reported that the grain refinement is very effective to strengthen the magnesium alloys. In this study, the influence of grain size on the tensile properties of three magnesium alloys has been investigated using specimens having grain sizes ranging from 100 nm to 100 µm. The grain size was changed by heat treatment after HPT processing, and the tensile tests have been made at an initial strain rate of 1.0×10−4 s−1. The grain refinement is effective for strengthening in the coarse-grained samples in which grain size is larger than 3 µm, but its effect decreases significantly in the fine-grained samples in which grain size is below 3 µm. This difference in effect of grain refinement has been discussed in relation to deformation mechanism.
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大沼 郁雄2019 年 69 巻 7 号 p. 340-347
発行日: 2019/07/30
公開日: 2021/06/15
ジャーナル フリーPDF形式でダウンロード (1707K)
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2019 年 69 巻 7 号 p. 358
発行日: 2019/07/30
公開日: 2019/08/30
ジャーナル フリーPDF形式でダウンロード (149K)
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