巻号一覧
71 巻, 5 号
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徳永 博文, 井手口 悟, 清水 史幸, 齊藤 敬高, 中島 邦彦2007 年 71 巻 5 号 p. 445-451
発行日: 2007年
公開日: 2007/05/02
ジャーナル フリーThe effect of RE2O3 (RE=Y, Gd, Nd, and La) additives on the surface tension of 45.2MgO-54.8SiO2 (mol%) melts have been investigated using the ring (detachment or maximum pull) method. Furthermore, the wettability of RE2O3-MgO-SiO2 melts between the silicon nitride polycrystalline substrate is determined using the sessile drop method.
The surface tension of RE2O3-MgO-SiO2 melts were found to increase with the content of any rare-earth additions, which suggests that a rare-earth oxide behaves as a network modifier of the complex silicate anions in high temperature melts. The surface tension increased in the order of the cationic radius of rare-earth oxides as follows: Y2O3<Gd2O3<Nd2O3<La2O3.
The contact angle of RE2O3-MgO-SiO2 melts against the silicon nitride substrate rapidly decreased with the annealing time at 1723 K; after annealing for 50 min, the contact angle remained constant. The contact angle and the penetration depth of melts into the substrate increased in the order of the cationic radius of rare-earth oxides as follows: Y2O3<Gd2O3<Nd2O3<La2O3.
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竹内 博晃, 横堀 壽光, 細野 真司, 小林 大輔, 佐藤 康二2007 年 71 巻 5 号 p. 452-457
発行日: 2007年
公開日: 2007/05/02
ジャーナル フリーThe Nickel based directionally solidified superalloy has been developed as a gas turbine blade material for high electrical efficiency power plant. Turbine blades are faced with the centrifugal stress from the high-speed rotation under high temperature creep conditions. In the present study, in order to clarify the effect of an oblique crack on the resistant of creep deformation and crack growth, analyses of elastic-plastic creep FEM using a penalty function were conducted.
The model of analysis used is a plate with double edge V notches and the type of elements used for analysis is 6-nodes isoparametric elements. Two type models for crack extension were considered such as straight-cracking and an oblique crack. The method of a crack extension is based on the increment application of inverse reaction and release of penalty function at the release nodes.
On the basis of the elastic-plastic-creep FEM analysis using a penalty function, it was found that creep crack growth behavior and deformation were characterized by the toughening effects induced by the constitution law of stress-strain rate for creep deformation and crack branch such as an oblique crack. The crack growth behavior derived by this analysis were found to be in good agreement with the corresponding experimental characteristics.
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半谷 禎彦, 北原 総一郎, 桑水流 理, 吉川 暢宏, 天田 重庚2007 年 71 巻 5 号 p. 458-462
発行日: 2007年
公開日: 2007/05/02
ジャーナル フリーThe porosity inside die castings influences the pressure resistance of the products. Especially, elongated porosity tends to become the air leakage path. We have investigated the post compression process of ADC12 aluminum alloy die castings to intercept the air leakage path through the porosity by closing some parts of elongated porosity. The closing behavior of porosity was affected by the shape and the distribution of porosity. In this study, two-dimensional image-based finite element analysis was performed to find the optimum compression condition considering the actual shape and distribution of porosity inside die castings. The finite element mesh was generated from X-ray CT images of the ADC12 aluminum alloy die casting specimen. The closing behavior of porosity obtained from experimental result and finite element analysis result is well conformed. We proved that the two-dimensional image-based finite element method is valid to estimate the optimum condition of the post compression process. We investigated the minimum compression rate to intercept the air leakage path both at room temperature and at high temperature by using the same two-dimensional image-based finite element mesh. In the manufacturing field, the temperature condition is also important. Especially at high temperature, the bonding of porosity after closing is expected.
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寺内 大輔, 星野 堅一, 岡田 大佑, 曾根 逸人, 保坂 純男2007 年 71 巻 5 号 p. 463-468
発行日: 2007年
公開日: 2007/05/02
ジャーナル フリーWe studied an imaging method for side wall surface of high aspect ratio structure in semiconductor devices by atomic force microscope (AFM). This method is based on conventional AFM methods (for example, contact mode AFM, non-contact mode AFM, tapping mode AFM, and so on) and is equipped with sample inclination mechanism using new XYZ scanner. As experimental results, we demonstrated that the inclination AFM method is very suitable to get detailed structure such as etching scratches on side walls with nanometer resolution.
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宮野 公樹, 則村 貴洋, 稲葉 輝彦, 飴山 惠2007 年 71 巻 5 号 p. 469-475
発行日: 2007年
公開日: 2007/05/02
ジャーナル フリーThe triangular phase in Ti-15V-3Cr-3Sn-3Al is observed after two-step aging. The three-dimensional shape of the phase is a triangular pyramid that is composed of three precipitates. The reason for the formation of the triangular shape is investigated by means of crystallographic analysis and high-resolution TEM observations. According to the HR-TEM observations, it is possible that the triangular phase has Potters orientation relationship with the matrix despite the existence of Burgers orientation relationship in an intragranular precipitate, as reported in previous studies. This suggests that in the alloy under consideration, the orientation relationship between the precipitate and the matrix is selectable in terms of lattice correspondence. As for the growth direction of the precipitate, an invariant line is investigated. In our previous study, the growth direction determined in trace analysis by TEM observation was mostly in agreement with the direction of the invariant line. Although the three precipitates have a common direction, which is [2110]α/[111]β, their invariant lines are not parallel with each other, i.e., [447]α1, [744]α2, and [474]α3. Therefore, the precipitates expand along each direction while growing and form a triangular shape.
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中野 敦, Nurul Taufiqu Rochman, 末吉 秀一2007 年 71 巻 5 号 p. 476-481
発行日: 2007年
公開日: 2007/05/02
ジャーナル フリーRecently, the global scale environmental problems have become a critical issue. In metallic material, not only the cost reduction and improvement of mechanical properties but also the decrease in environmental load is required. In copper alloys, several mass%Pb was added to improve their machinability. However, due to the adverse toxicity of Pb, which is harmful to health, a new regulation to limit the amount of Pb permitted in drinking water supplies has been enforced. A huge amount of copper alloys scrap containing Pb will become industrial waste due to its unavailability as a raw material.
In order to promote the recycle of copper alloys scrap containing Pb, we developed a new technique for removing Pb from copper alloys scrap. By adopting this new technique, Pb was removed from brass and bronze using compound-separation method.
Copper alloys containing 2-6 mass%Pb were molten using a high-frequency induction furnace under nitrogen atmosphere. Ca-Si and NaF compounds were added into the molten copper alloys to form large particles of Pb compound. Then, these large particles of Pb compound were skimmed off from the molten copper alloys. Liquid metal extraction and casting was characterized by electron probe microanalyser (EPMA) and fluorescence X-ray (XRF) analysis.
The results show that high percentage (83% in brass and 82% in bronze) of Pb removal can be achieved.
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坂村 喬史, 斎藤 英之, 本間 啓史, 波多野 雄治, 長坂 琢也, 室賀 健夫, 中村 幸男2007 年 71 巻 5 号 p. 482-487
発行日: 2007年
公開日: 2007/05/02
ジャーナル フリーTritium radioluminography has been applied to the observation of tritium distribution in electro-chemically tritium charged pure V and V-4Cr-4Ti alloy (NIFS-HEAT-2) specimens, and the relation between the tritium distribution and the microstructure has been examined.
In the cold rolled V-4Cr-4Ti alloy specimen, tritium distribution showed band-like morphology along the rolling direction. This tritium accumulated band is corresponded to the band-like structure formed by high densely precipitated fine Ti granules. On the other hand, band-like morphology of tritium accumulation was not observed in the pure V and Ti-precipitation free V-4Cr-4Ti alloy specimen. The Ti-precipitate is concluded to be a strong trapping site for tritium. The tritium segregation to the grain boundary was not recognized both in the pure V and V-4Cr-4Ti alloy specimen indicating that the trapping power of the grain boundary for tritium is weak.
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