巻号一覧
59 巻, 12 号
December
選択された号の論文の13件中1～13を表示しています
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研究論文
研究論文
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—元素物質，AB型化合物，鉄系および銅系化合物—巻野 勇喜雄, 吉村 一良2012 年 59 巻 12 号 p. 665-673
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスThe relation between the superconducting critical temperature, Tc, and the effective pseudopotential radius, r(eff), was examined for elements, AB-type compounds, and Fe- and Cu-based compounds. Here, assuming arbitrarily their bonding states hybridized with valence electrons, we estimated r(eff) for the materials from the pseudopotential radii given for s, p, and d electrons. It is suggested that Tc can be estimated from the linear relation between Tc and N(v)r(eff)3, where N(v) is the effective number of valence electrons. For the elements with relatively high Tc such as Nb, Tc, and V, for those in AB compounds, and for Cu and Fe in their cuprates, pnictides, and chalcogenides, the value of Tc was found to vary almost linearly to N(v)r(eff)3 by assuming the p3dn or sp2dn hybridization. These findings suggest that the p3dn or sp2dn hybridization is a key bonding character to realize high Tc. For some of the compounds containing transition elements, however, the data deviate largely from the linear relation, indicating that the validity of the present argument is limited in such a category.抄録全体を表示PDF形式でダウンロード (1094K)
特集：各種粉末の焼結機構と新しい焼結技術の展開
総報
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川崎 亮2012 年 59 巻 12 号 p. 676-
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスPDF形式でダウンロード (125K)
研究論文
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Wan Sharuzi WAN HARUN, Toshiko OSADA, Hyungoo KANG, Fujio TSUMORI, Hi ...2012 年 59 巻 12 号 p. 677-684
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスThe influence of nickel particle sizes, nickel mass%, and sintering temperatures on the microstructure and mechanical properties of injection molded Fe-Ni compacts have been studied. The mixed elemental carbonyl iron and water-atomized nickel powders were utilized in this study. Tempered compact added 6 mass% fine nickel powder which was sintered at 1250°C for 1 hour showed superhigh strength of 2040 MPa with elongation of 8.1 %, the best properties among reported data in MIM low alloy steel compacts. These excellent mechanical properties by fine heterogeneous microstructure of the compact are explained in terms of the complicated networks of nickel content variation throughout the steel matrix.抄録全体を表示PDF形式でダウンロード (1779K) -
岩岡 拓, 中村 満2012 年 59 巻 12 号 p. 685-692
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスThe method of preparing magnesium-sintered alloy using pulsed current pressure and element powders was studied. Aluminum and zinc are general alloying elements for magnesium die casting. The Mg-Al-Zn powder mixtures were prepared by mixing such element powders, and consolidated by pulsed current pressure. The transverse rupture strength of the sintered compacts was influenced by compacting pressure during the increase of temperature. The sintering property of the compacts was estimated by comparing the transverse rupture strength. The transverse rupture strength of the pure magnesium compacts formed at a uniaxial pressure of 10 MPa during heating was about 2.7 times higher than that of 50 MPa. In other words, it is desirable that the compacting pressure is low when the powder mixtures are heated by pulsed current. The transverse rupture strength of the Mg-Al-Zn compacts prepared by this low compacting pressure was compared with that of as-cast.抄録全体を表示PDF形式でダウンロード (2451K)
研究速報
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日比野 敦, 呉 龍太郎2012 年 59 巻 12 号 p. 693-699
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスIn order to analyze the combustion synthesis reactions of Co-Al intermetallic compounds, Co/Al premixed compacts were quenched during the combustion synthesis. Additionally, Co wires were dipped into molten Al, and the compound formation reactions between Co and molten Al were investigated.
From microstructure observation, SEM-EDX analysis and X-ray analysis of the quenched compacts, molten Al phase, un-reacted Co phase, and CoAl3 intermetallic compound phase were found. The CoAl3 compound phase was also found in the Co wire dipped into the molten Al. The thickness of the CoAl3 compound layer in the dipped wire depended on dipping temperature and dipping time. Therefore, Co-Al intermetallic compounds were formed via CoAl3 formation reaction during the combustion synthesis. Form above results and Co-Al phase diagram, the following reaction equations were suggested in the combustion synthesis of Co-Al intermetallic compound.
Al(s)→Al(l) (933 K)
Co(s)+Al(l)→CoAl3(s) (933∼1408 K)
CoAl3(s)→Co2Al5+(Al-Co) Liq. (1)→CoAl+(Al-Co) Liq. (1) (1408 K∼1453 K)
Co(s)+(Al-Co) Liq. (1)+CoAl(s) (1453 K∼)抄録全体を表示PDF形式でダウンロード (1644K) -
日比野 敦, 伊藤 賢良2012 年 59 巻 12 号 p. 700-706
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスIn order to analyze the combustion synthesis reactions of Mo-Al intermetallic compounds, Mo/Al premixed compacts were quenched during the combustion synthesis. Additionally, Mo wires were dipped into molten Al, and the compound formation reactions between Mo and molten Al were investigated.
From microstructure observation, SEM-EDX analysis and X-ray analysis of the quenched compacts, molten Al phase, unreacted Mo phase, and MoAl5, MoAl4 intermetallic compound phases were found. These MoAl5 and MoAl4 compound phases were also found in the Mo wire dipped into the molten Al. The MoAl5 phase was synthesized below 1008 K, and MoAl4 phase was formed over 1008 K. Therefore, Mo-Al intermetallic compounds were formed via MoAl5, MoAl4 formation during the combustion synthesis. Form above results and Mo-Al phase diagram, the following reaction equations were suggested in the combustion synthesis of Mo-Al intermetallic compound.
Al(s)→Al(l) (933 K)
Mo(s)+Al(l)→MoAl5(s) or Mo(s)+Al(l)→MoAl4(s) (933∼1403 K)
MoAl4(s)→Mo3Al8+(Al-Co) Liq. (1)
Mo(s)+(Al-Co) Liq. (1)+Mo3Al8(s)抄録全体を表示PDF形式でダウンロード (2163K)
研究論文
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日比野 敦2012 年 59 巻 12 号 p. 707-713
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスIn the previous paper, dipping experiments of metal wires (metal=Mo, Co) into molten Al were investigated to analyze the combustion synthesis of Mo-Al and Co-Al intermetallic compounds. From the dipping experiment, it was found that MoAl4 and CoAl3 compound layers were formed between the metal wires (Mo, Co) and the molten Al. The compound formation reactions were analyzed by a cylindrical reaction model that the outer side was the molten Al, central cores were the metal wires(Mo, Co), and intermediate layers were the intermetallic compounds(MoAl4, CoAl3).
The compound formation reactions were able to be simulated by calculating the cylindrical model. The values calculated by the model agreed with the experimental value. The following reaction parameters were obtained from the model calculation for the Mo-Al system.
LogDAl/m2·s−1=−9.813×102/T−10.243
Logkc/mol·m−2·s−1=−9.696×102/T−1.755
It was suggested that the reaction rate was controlled by the diffusion process of Al and the chemical reaction process, from the reaction resistances calculation using the cylindrical model. Additionally, the numerical analysis by the cylindrical model was performed for Co-Al system.抄録全体を表示PDF形式でダウンロード (1583K)
解説
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水内 潔, 井上 漢龍, 上利 泰幸, 川原 正和, 巻野 勇喜雄, 井藤 幹夫2012 年 59 巻 12 号 p. 714-720
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスIn order to fabricate high-performance thermal management materials with ultra-high thermal conductivities and low CTEs, we have recently initiated a series of investigations, where metal-matrix composites (MMCs) containing high thermal conductive fillers were uniquely fabricated. In our study, to avoid the damage of filler particle surfaces, spark plasma sintering (SPS) processing was used as a processing technique. In the present review, thermal properties of diamond particle dispersed MMCs fabricated using SPS process in our recent works are introduced in comparison with those produced using various fabrication techniques by other researchers.抄録全体を表示PDF形式でダウンロード (1304K) -
若井 史博2012 年 59 巻 12 号 p. 721-727
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスMany sintering bodies shrink in an anisotropic manner when the particle packing is not isotropic. In the continuum mechanics frame work, macroscopic shrinkage in sintering is described as a linear function of the sintering stress tensor and the viscosity tensor. These macroscopic quantities are determined rigorously from local microstructure and microscopic kinetics involving grain boundary diffusion. The shrinkage is driven by the hydrostatic component of the sintering stress tensor, while the anisotropic deformation is driven by its deviatoric components. This model is able to predict both the evolution of the anisotropic microstructure during sintering, and also the effect of the local microstructure on anisotropic shrinkage.抄録全体を表示PDF形式でダウンロード (1525K)
本会記事
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2012 年 59 巻 12 号 p. Pref12_1-
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスPDF形式でダウンロード (132K) -
2012 年 59 巻 12 号 p. Mtg12_2-Mtg12_5
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスPDF形式でダウンロード (632K) -
2012 年 59 巻 12 号 p. 728-
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスPDF形式でダウンロード (48K) -
2012 年 59 巻 12 号 p. Index59_1-Index59_16
発行日: 2012/12/15
公開日: 2013/01/23
ジャーナル オープンアクセスPDF形式でダウンロード (855K)
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