粉体および粉末冶金
Online ISSN : 1880-9014
Print ISSN : 0532-8799
ISSN-L : 0532-8799
53 巻, 10 号
October
選択された号の論文の9件中1~9を表示しています
研究
研究
  • 清水 透, 松崎 邦男, 佐野 利男
    2006 年 53 巻 10 号 p. 791-796
    発行日: 2006年
    公開日: 2007/02/09
    ジャーナル オープンアクセス
    A new rapid manufacturing process of metallic parts using green machining has been developed. In this process, metal powder for metal injection molding is hardened using water base binder, and made into a green body. After drying the green body, it is machined by small automatic milling machine. Machined parts are sintered after that, and rapidly manufactured parts are obtained. In this process, the green body has enough strength for machining, and we can use a small, cost-effective milling machine developed for wood or plastic materials. The machining time of the green body is short compared with other material processing. We can obtain low cost rapid prototyping of metallic parts by this green machining process.
  • 清水 透, 岡田 智史, 松崎 邦男, 淵沢 定克
    2006 年 53 巻 10 号 p. 797-802
    発行日: 2006年
    公開日: 2007/02/09
    ジャーナル オープンアクセス
    A new rapid manufacturing process of metallic parts using green machining has been developed and already achieved for manufacture of stainless steel parts. In this process, metal powder for metal injection molding is hardened by a solution of PVA in water as binder. This green body is prepared for machining. This process is used a small and cost-effective milling machine, and the green body is easily machined. Meanwhile, rapid manufacturing of titanium parts for implant is desired in the medical field. This process makes it possible to produce a suitably sized medical implant. Therefore, we applied the green machining process to the production of titanium parts for the purpose of manufacturing implants with law cost and short lead-time.
特集:金属および複合材料系における焼結機構と新しい焼結技術の展開
総報
研究速報
研究
  • 森口 秀樹, 都築 克典, 池ヶ谷 明彦, 宮本 欽生
    2006 年 53 巻 10 号 p. 809-814
    発行日: 2006年
    公開日: 2007/02/09
    ジャーナル オープンアクセス
    Mechanical properties of ultra-fine grained cemented carbides with 12wt% Co binder produced by pulsed-electric current sintering were compared with those of cemented carbides by conventional vacuum sintering. The cemented carbides prepared by pulsed-electric current sintering had 6% higher hardness and 23% higher fracture toughness. These excellent properties seemed to be caused by ultra-fine WC grains and flattened Co phase in the sintered compacts. The flattened Co phase tended to be arranged in a perpendicular direction against a pressurized direction during sintering. However the increasing effect of fracture toughness by the flattened Co became small according to decreasing of Co contents. The fracture toughness of the compacts with Co binder less than 2wt% Co sintered by pulsed-electric current process was about 8% smaller than that by conventional process. But the hardness was about 20% higher than that by conventional process. The transverse rapture strength of ultra-fine grained cemented carbides sintered by pulsed-electric current process was about 28% smaller than that by conventional process.
  • 三浦 秀士, 竹増 光家, くわ野 友紀, 伊藤 芳典, 佐藤 憲治
    2006 年 53 巻 10 号 p. 815-820
    発行日: 2006年
    公開日: 2007/02/09
    ジャーナル オープンアクセス
    In this study, the metal injection molding process was applied to produce the sintered titanium alloy compacts using pre-alloyed Ti-6Al-4V powders obtained by gas atomization. The effect of sintering conditions on the density, mechanical properties, and oxygen and carbon contents were investigated as compared to using mixed Ti and 60Al-40V powders. The mechanical properties (Tensile strength of 890 Mpa, Elongation of 10%) of injection molded compacts using pre-alloyed powder were comparable to the wrought Ti-6Al-4V material of JIS 60 grade. In such a case, the injection molded compacts using mixed powders showed high density and high properties (Relative density of 98%, Tensile strength of 910Mpa, Elongation of 14%) as compared to the compacts using pre-alloyed powder.
  • 伊藤 芳典, 植松 俊明, 佐藤 憲治, 三浦 秀士, 新家 光雄, 池田 勝彦
    2006 年 53 巻 10 号 p. 821-826
    発行日: 2006年
    公開日: 2007/02/09
    ジャーナル オープンアクセス
    The metal injection molding process was used to produce the Ti-4.3Fe-7.1Cr alloy compacts using the mixture of Ti and Fe-Cr alloy powders, and mixed elemental powder. The effect of mixed powder and sintering temperature on the densification behavior, mechanical properties and microstructures of the compacts were mainly investigated. The compacts sintered at below 1423K using a mixed elemental powder showed higher density and tensile strength as compared to the compacts using a mixture of Ti and Fe-Cr alloy powders. However, the tensile elongation at fracture of sintered compacts using both mixed powders was about 3%. Characteristic X-ray images and X-ray diffraction measurement confirms a particle dispersion, which is thought to be precipitation of α Ti phase, along the grain boundaries. Eventually, the tensile strength and relative density of the compacts sintered at 1423K using a mixed elemental powder attain 1160MPa and 96.9%, respectively.
資料
研究
  • 三沢 達也, 鹿谷 昇, 川上 雄士, 円城寺 隆志, 大津 康徳, 藤田 寛治
    2006 年 53 巻 10 号 p. 830-835
    発行日: 2006年
    公開日: 2007/02/09
    ジャーナル オープンアクセス
    The influence of the internal current for the ZnO ceramics on the sintering behavior by pulse current sintering (PCS) method was investigated. The electric resistance of the sintering ZnO ceramics drastically decreases by the addition of the small Al2O3, and it is expected that a part of sintering current flows in the specimen and affects the sintering behavior of the ZnO ceramics on the PCS method. To clear the dependence of inner current on the sintering behavior of ZnO ceramics, direct measurement of electric resistance of ZnO specimen under sintering by SPS device was carried out. It was observed that electric resistance of specimen decreases with increase in the temperature. The electric resistance begins to decrease from the low temperature of 200°C. The internal structure of sintered ZnO ceramics changed by the control of the internal current in the specimen using Al2O3 plate.
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