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59 巻, 2 号
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研究論文
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土田 信原稿種別: 研究論文
2009 年 59 巻 2 号 p. 63-69
発行日: 2009/02/28
公開日: 2009/03/31
ジャーナル フリーAnisotropy of Lankford value (r value) were measured and discussed in the relation with crystallographic textures and ear behavior in the 3004 aluminum alloy sheet strain hardened by cold rolling of 86% total reduction after the hot rolling. The rvalue is small in 0° direction from the rolling direction and maximum in near 90° direction as the tensile strength shows the similar distribution. Typical and well developed rolling textures containing weak Cube, RD rotated cube and Goss components are observed in the material. The distribution profile of r value near 30° to 90° direction is estimated to depend on these texture components, however, the small r value in 0° direction is not consistent with the r value which is calculated by Taylor's model using the measured ODF's data. The actual small r value in 0° direction is considered to be caused by not only the crystallographic textures but also the deformation by shear bands that are located parallel to the transverse direction with an angle of 35° from the rolling plane. The characteristic ears in the drawn cup of this material that are six ears at 45° and 0°/180° position seem to correspond to the anisotropy of r value.抄録全体を表示PDF形式でダウンロード (2783K) -
高谷 松文, 前嶋 正受原稿種別: 研究論文
2009 年 59 巻 2 号 p. 70-74
発行日: 2009/02/28
公開日: 2009/03/31
ジャーナル フリーUtensils made of titanium and it's alloys have recently been employed in various branches of medical treatment, welfare, recreation and sports due to their light weight, excellent corrosion resistance and artistic design potential. However, utensils made of titanium and it's alloys are more subject to easy seizure, scuffing, abrasive wear and adhesive wear than utensils made of steel. This study seeks to improve the tribological properties of titanium and it's alloys by applying a porous anodic oxide film anodized in a suitable electrolytic solution made up H2SO4, H3PO4 and H2O2. The method employs 5,000 Hz pulses in direct current to anodize utensils and impregnate them with molybdenum sulfide while they adsorb zinc sulfide using electrophoresis at the same time. Based on this study, we were able to attain a lower friction coefficient, a narrower wear trace, and a lower ratio of wear volume after this surface treatment. We presume that the chemical composition of zinc sulfide resolved during friction and wear converts molybdenum sulfide to MoS2, a well known lubricant, as a result of reciprocal action.抄録全体を表示PDF形式でダウンロード (2775K) -
阿部 真丈, 信木 関, 久慈 俊郎原稿種別: 研究論文
2009 年 59 巻 2 号 p. 75-80
発行日: 2009/02/28
公開日: 2009/03/31
ジャーナル フリーThe crystallization behavior of the Mg–Al alloy (initial ratio Mg : Al=17:12) prepared by ball-milling (BM) was studied by means of X-ray diffractometry (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the case of a short BM time (18ks), we could prepare the mixture of nano-sized Mg and Al grains. And the post annealing of the mixtures at even T<373 K yielded formation of the fine and low strained Mg17Al12 phase. In fact, the DSC analysis showed that only the sample after 18 ks of BM had a distinct exothermic peak at 373 K, corresponding to the formation of the Mg17Al12 and consisted of the compound from nano Mg and Al grains. The samples prepared for longer BM (144ks) did not show equivalent the formation peak time. These samples were composed of nano-sized Mg17Al12 phase with heavy strained due to mechanical energy. In addition, the Mg17Al12 synthesized from the sample after 18 ks of BM is superior in hydrogen properties to the sample after 144 ks of BM.抄録全体を表示PDF形式でダウンロード (2264K) -
安藤 誠, 菅野 幹宏, 一谷 幸司, 茂木 轍一原稿種別: 研究論文
2009 年 59 巻 2 号 p. 81-86
発行日: 2009/02/28
公開日: 2009/03/31
ジャーナル フリーEffects of alloy compositions on hydrogen embrittlement was studied by means of slow strain rate testing, using Al–Mg–Si based alloys containing different amounts of excess Si, Mg2Si and Cu. An Al–1.12 mass%Mg2Si–0.35 mass%Si alloy hardly showed degradation in ductility when tested at the strain rate of 10−7/s in a high humidity atmosphere of 90% R.H, compared to the ductility obtained by testing at the strain rate of 10−4/s. In contrast, the ductility of an Al–1.11%Mg2Si–0.81%Si alloy obtained by testing at 10−7/s was lower than that at 10−4/s in the humid air. By means of SEM/EDS analysis, Si-rich precipitates were observed on intergranular fracture surfaces of the embrittled alloy. These results suggested that hydrogen embrittlement was clearly observed with an increase in excess Si content. The ductility of an Al–1.81%Mg2Si–0.80%Si alloy obtained by testing at 10−7/s, however, was larger than that at 10−4/s in the humid air. The same tendency was observed in commercially available 6070, 6013 and 6066 aluminum alloys. These results meant that the Al–Mg–Si based alloys with excess silicon contents did not always show hydrogen embrittlement. Discussion was made on the above phenomena.抄録全体を表示PDF形式でダウンロード (2242K)
解説
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高杉 篤美原稿種別: 解説
2009 年 59 巻 2 号 p. 87-93
発行日: 2009/02/28
公開日: 2009/05/30
ジャーナル フリーPDF形式でダウンロード (4265K)
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