巻号一覧
58 巻, 1 号
January
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
研究
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平山 悠介, 岡田 裕之, 中川 貴, 山本 孝夫, 楠瀬 尚史, 入江 年雄, 中村 英次2011 年 58 巻 1 号 p. 3-7
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスSpherical GdN material with diameter of 0.85 ∼ 1.0 mm was synthesized by the hot isostatic pressing (HIP) method aiming at the application to the magnetic refrigeration for hydrogen liquefaction. Conditions of the HIP nitridation starting from metallic Gd spheres were investigated to obtain the spherical GdN materials free from unwanted deformation and/or cracks. We found that slower temperature rising rate, 10°C/h, around the melting point of Gd metal, 1300-1600°C, is favorable because it would allow the metallic Gd core to transform into nitride by reacting with nitrogen diffusing from the surface. We have successfully synthesized spherical GdN material of 300 g, which is enough to operate a test device for the magnetic refrigeration. Oxidization degree of this spherical GdN material was investigated by exposing it to air with some controlled humidity. It was found that only 2.5 % of the GdN was degraded after 56 hour exposition to air dried with silica gel.抄録全体を表示PDF形式でダウンロード (849K)
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2011 年 58 巻 1 号 p. 10
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスPDF形式でダウンロード (135K)
解説
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渡辺 義見, 三浦 永理, 佐藤 尚2011 年 58 巻 1 号 p. 11-17
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスFabrication methods of functionally graded materials (FGMs) under centrifugal force are classified into three categories, namely centrifugal method (application of centrifugal casting), centrifugal slurry method and centrifugal pressurization method (simple pressurization by the centrifugal force). The latter two methods can combine with sintering method. In this article, fabrication of FGMs by combination of centrifugal force and sintering method is described.抄録全体を表示PDF形式でダウンロード (1850K)
研究
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Hiroshi Kimura, Ryoichi Shimoitani2011 年 58 巻 1 号 p. 18-26
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスIn order to manufacture a pore free amorphous Ti50Al50 product, a pulse electric current sintering of the mechanically alloyed amorphous powder under high-pressure is proposed, with which one can obtain full densification at low temperatures prior to glass transition to a supercooled liquid. The compressibility (Cm) of the amorphous Ti50Al50 powder follows a simplified Cooper-Eaton equation of Cm =Aexp(-k/P) under the applied stress of up to 600 MPa at room temperature, indicating that the powder compaction proceeds mainly via local plastic deformation at their contacted area with nearly non-strain hardening. When a high applied pressure of 600 MPa is used with a specially designed WC die, the amorphous Ti50Al50 powder can be consolidated at a full-density up to 939 K below a glass temperature, avoiding major crystallization; its densification during electric current heating is fairly well expressed with a commonly used equation of Non-Newtonian flow: ε=ε0 sin h(cσeff/kT)exp(-Hp/kT) with a decreased value of 50 kJ mol-1 for the apparent activation energy, Hp. Dynamic nanoindentation is used to give the value of 0.65 GPa for the level of yield stress for the fully dense amorphous Ti50Al50 sample.抄録全体を表示PDF形式でダウンロード (1711K) -
中村 英文, 豊島 寿隆, 大津 秀則, 千葉 晶彦, 阿部 孝悦2011 年 58 巻 1 号 p. 27-32
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスSintering of Zr pre-alloyed and water atomized 316L stainless steel powder for various content of Si was performed. The maximum sintered density was obtained at 0.8 mass% of Si for the powder pre-alloyed 0.05 mass% of Zr. Excess addition of Si -for example, 1.20 mass%- inhibited the densification by the growing of Si-containing oxide particles. The pre-alloying of Si increased the ferrite content of powder but the correlation between the ferrite content and the level of densification was not observed. The 316L powder pre-alloyed 0.8mass%Si and 0.05mass%Zr had finer grain size and this made a contribution to the densification by the volume diffusion.抄録全体を表示PDF形式でダウンロード (3044K) -
池田 光, 岩橋 孝典, 長田 稔子, 三浦 秀士2011 年 58 巻 1 号 p. 33-37
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスSuperalloys have been used especially for aerospace and atomic energy applications because of their excellent attributes of high corrosion and oxidation resistance, and high temperature strength. A Inconel 718 is one of representative Ni-base superalloys. However, it is not easy to produce the complicate shaped parts with low cost due to their poor workability. In this study, Metal Injection Molding (MIM) process, one of near net-shape forming of powders, has been applied to fabricate the Inconel 718 alloy compacts using different type of powders; gas and water atomized powders. By optimizing the MIM process, their obtained relative density was near full density (98∼99 %) and the tensile property of as-sintered compacts was the strength of 1000 MPa and the elongation of around 10 %, which are similar to those of wrought materials. The tensile properties were improved to the strength of 1250 MPa and the elongation of around 8 % by heat treatment.抄録全体を表示PDF形式でダウンロード (1444K) -
中村 英文, 豊島 寿隆, 大津 秀則, 千葉 晶彦, 阿部 孝悦2011 年 58 巻 1 号 p. 38-44
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセス2mass%Ni-Fe sintered parts are, at present, produced by premixed method using carbonyl iron powder and carbonyl nickel powder as principal raw materials. In this study, the production method of sintered parts using Zr pre-alloyed and water atomized 2mass%Ni-Fe alloy powder as raw material was investigated. Followings were observed;
1) By pre-alloying with about 0.8 mass% of Si, Zr pre-alloyed 2mass%Ni-Fe alloy obtained the sintered density comparable to the conventional premixed method.
2) The Si pre-alloying increased the surface energy of powder, and the activated surface diffusion, and thereby promoted formation of necks.
3) The addition of carbon as alloying element obstructed the densification in lower sintering temperature, but, in higher temperature, promoted the densification by consuming oxygen with C-O reaction.
4) The sintered parts of Zr and Si pre-alloyed 2mass%Ni-Fe alloy powder contained not only less pores and inclusions but also uniformly-sized grains. These resulted in higher values of tensile strength and hardness but lower elongation.
5) By carburizing and quenching, the sintered parts of Zr and Si pre-alloyed 2mass%Ni-Fe alloy powder showed mechanical properties and hardness higher than those of the conventional premixed method. These values were controllable with adjusting of tempering temperature.抄録全体を表示PDF形式でダウンロード (3366K) -
中込 洋平, 樋田 翔吾, 望月 友仁, 藤間 卓也, 高木 研一2011 年 58 巻 1 号 p. 45-49
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスEffect of particle size distribution on the density and shrinkage of gas-atomized ferrous alloy powder compacts were investigated by controlling particle size distribution of the two bimodal ferrous alloy powders (-25 μm/125-150 μm, 25-46 μm/125-150 μm). These powders were sintered at 1473 K in vacuum after compacted at the pressure of 490 MPa. As a result, the sintered compact of -25 μm/125-150 μm bimodal powder with fine powders content 35 mass% showed higher density and lower shrinkage ratio than those of other powder compacts. The improvement of particle packing depended strongly on the size ratio and mixing ratio of the fine to coarse powder.抄録全体を表示PDF形式でダウンロード (628K)
解説
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京極 秀樹, 寺山 朗2011 年 58 巻 1 号 p. 50-56
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスRecently, the fabrication of Ti-based shape memory alloys (SMAs) has been tried using the powder metallurgy (PM) process. The fabrication conditions of Ti-based SMAs by PM process and their important shape memory characteristics for applying to the elements, however, have not been discussed enough. The target of this study is to develop Ti-based SMAs having superior shape memory characteristics by PM process. At first, the fabrication conditions and shape memory characteristics of Ti-Ni alloys were examined. Next, in order to improve the critical stress for slip deformation and the shape memory characteristics of Ti-Ni alloys, the effects of aging treatment, densification processing and addition of Cu and Zr as third elements on the shape memory characteristics were investigated. In this paper, the effects of Cu addition on phase transformation behavior and thermo-mechanical properties of Ti-Ni-Cu alloy were introduced. As a result, Ti-based SMAs having superior shape memory characteristics could be developed by establishment of fabrication conditions of the alloy by the PM process.抄録全体を表示PDF形式でダウンロード (1278K)
研究
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大浦 峻典, 林 秀考, 岸本 昭2011 年 58 巻 1 号 p. 57-62
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスWith the aim to improve the thermal conductivity of yttria dispersed AlN ceramics through a short time and low temperature treatment under nitrogen atmosphere, millimeter wave (MMW) heating was combined with post-HIP treatment. Relative density increased by post HIP treatment over 1600°C on previously MMW heated samples even with the same temperature. The thermal conductivity exceeded over 170 W/m·K when treated through MMW-HIP combined sintering with 1700°C + 1700°C treatment by 0.5 h + 0.5 h. This valued had been attained through the MMW treatment alone at 1800°C for 2 h under 3 wt% hydrogen mixed nitrogen atmosphere. The optimal dispersion amount was 3 wt% in the MMW-HIP combined sintering while that was 5 wt% in the MMW sintering alone. The relative density has been saturated at the first MMW heating over 1700°C. On the other hand, thermal conductivity increased with the treatment temperature both in first MMW and post HIP. No significant pressure dependence can be seen in the thermal conductivity with this experimental condition.抄録全体を表示PDF形式でダウンロード (1041K)
受賞記念講演
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水内 潔, 川原 正和, 巻野 勇喜雄2011 年 58 巻 1 号 p. 63-70
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスDiamond-particle-dispersed-aluminum (Al) matrix composites were fabricated in a unique fabrication method where continuous solid-liquid coexistent state of the powder mixture of diamond, pure Al and Al-5mass%Si alloy was designed during spark plasma sintering (SPS) process. Microstructures and thermal properties of the composites fabricated in such a way were investigated. The composites can be well consolidated in the temperature range between 798 K and 876 K and scanning electron microscopy detects no reaction at the interface between the diamond particle and the Al matrix. The relative packing density of the diamond-Al composite fabricated was 99 % or higher in a volume fraction range of diamond between 35 and 50 %. The thermal conductivity of the diamond-Al composite containing 50 vol.% diamond reached 552 W/mK, higher than 95 % the theoretical thermal conductivity calculated by Maxwell-Eucken's equation. The coefficient of thermal expansion of the composites falls in the upper line of Kerner's model, indicating strong bonding between the diamond particle and the Al matrix in the composite. Based on the experimental results obtained in the present study, densification process in continuous solid-liquid co-existent state is considered to be a quite effective methodology for enhancing performance of heat dissipative metal matrix composites.抄録全体を表示PDF形式でダウンロード (1635K)
本会記事
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2011 年 58 巻 1 号 p. Pref1_1
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスPDF形式でダウンロード (95K) -
2011 年 58 巻 1 号 p. Mtg1_2-Mtg1_5
発行日: 2011年
公開日: 2011/05/13
ジャーナル オープンアクセスPDF形式でダウンロード (260K)
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