粉体および粉末冶金
Online ISSN : 1880-9014
Print ISSN : 0532-8799
ISSN-L : 0532-8799
60 巻, 4 号
April
選択された号の論文の9件中1~9を表示しています
研究論文
技術速報
研究論文
  • 宇波 繁, 尾崎 由紀子, 三阪 佳孝, 深沢 剣吾
    2013 年 60 巻 4 号 p. 141-145
    発行日: 2013/04/15
    公開日: 2013/05/16
    ジャーナル オープンアクセス
    The fatigue strength of the sintered and super rapid induction heated and quenched (SRIQ) compact made of the 0.6 mass% Mo - 0.2 mass% Mn prealloyed steel powder has been investigated. As the effective case depth in the SRIQ material decreased, fatigue strength increased, and reached to 400 MPa equivalent to two times of the carburized material in the case of 1 mm of the effective case depth. Moreover, fatigue strength of 500 MPa was obtained by double SRIQ treatment, in which specimens was quenched to the center region in the first SRIQ, and to 1 mm of the effective case depth in the subsequent treatment. The improvement in the fatigue strength can be considered to result from not only the high compressive residual stress but also the fine prior austenite grain.
  • 辻 広美, 村上 隆, 宮崎 敬士, 橋本 英樹, 團野 瑛章, 草野 圭弘, 菊地 孝宏, 中西 真, 藤井 達生, 高田 潤
    2013 年 60 巻 4 号 p. 146-153
    発行日: 2013/04/15
    公開日: 2013/05/16
    ジャーナル オープンアクセス
    To clarify the detailed features of the red bengala samples excavated from the Shimo-ohgibaru archaeological site in the late Yayoi period (2nd to 3rd century A.D.) from the viewpoint of materials science, colorimetric measurements, X-ray fluorescence analyses, X-ray diffraction measurements, transmission electron microscope observations, and surface area measurements of the ancient bengala samples were achieved. The ancient bengala sample was found to be high purity α - Fe2O3. The features of the color tone and particle size of the ancient bengala were clarified by comparing with those of commercially available bengala, Fukiya bengala, and synthesized α-Fe2O3. In addition, the starting materials and synthesis processes of the ancient bengala were discussed by applying the elutriation experiments of representative natural hematite and heat-treated natural iron hydroxide (Oniita).
  • 世利 修美, 岩間 孝明, 佐々木 大地
    2013 年 60 巻 4 号 p. 154-159
    発行日: 2013/04/15
    公開日: 2013/05/16
    ジャーナル オープンアクセス
    Attempts have been made to obtain the cobalt spinel (CoAl2O4) by using corrosion of cobalt and aluminium chloride as catalysis. A few micron size powder was obtained when the corrosion product was hydrolyzed and calcinated at the temperature of 1073 K or more. The powder was identified as CoAl2O4 spinel by XRD diffraction analysis. Corrosion synthesis as one of the inorganic syntheses is explained from the viewpoint of electrochemical phenomena and considered its merits and demerits in the case of making the spinel of CoAl2O4.
  • 山田 雄介, 藤原 弘, 宮本 博之, 飴山 惠
    2013 年 60 巻 4 号 p. 160-166
    発行日: 2013/04/15
    公開日: 2013/05/16
    ジャーナル オープンアクセス
    Harmonic structured materials with fine and coarse grains demonstrate not only enhanced strength but also enough ductility simultaneously. The harmonic structured material consists of a network like a fine grain region and a dispersed coarse grain region. The high strength and enough ductility are attributed to the network fine grain region and the dispersed coarse grain region, respectively. In this study, the harmonic structured metallic composite with high speed steel (HSS) and low carbon steel (LCS) is fabricated by mechanical milling and spark plasma sintering process. The harmonic structured HSS/LCS composite consists of the network like fine grain region with HSS and dispersed coarse grain region with LCS. The hardness of the harmonic structured composite with HSS and LCS is higher than the conventional particle dispersed composite with the same HSS volume fraction.Furthermore, the harmonic structured composite with HSS and LCS indicates high tensile strength without ductility loss, compared to the conventional HSS particle dispersed composite with the same HSS volume fraction. The harmonic structure control of composite materials is effective to improve the mechanical properties with enough ductility maintained.
総説
  • 堀田 善治
    2013 年 60 巻 4 号 p. 167-178
    発行日: 2013/04/15
    公開日: 2013/05/16
    ジャーナル オープンアクセス
    In this review paper, high-pressure torsion (HPT) is introduced as a processing tool for powder consolidation. It is shown that not only HPT can refine the grain size to the submicrometer and/or nanometer range in bulk metallic materials but also can achieve consolidation of metallic and ceramic powders including mechanical alloying, synthesis of intermetallics, allotropic phase transformation and fabrication of metal-matrix composites. Supersaturation of Fe in ultrafined grained Al is achieved in the Al - Fe system where Fe solubility in Al is as little as 0.052 mass%. Allotropic phase transformation of Ti and Zr occurs from α phase to ω phase during operation of HPT because of high pressure in comparison with the conventional ball milling process. Nanograined NiAl and TiAl intermetallics form by HPT processing including successive annealing at temperatures as low as ~0.35Tm where Tm is the melting temperature of the intermetallics. Fabrication of composites is feasible with nano ceramic particles dispersed in the metal matrix. Finally, applications of HPT to ceramics such as Al2O3 and ZrO2 demonstrate that it is possible to introduce plastic strain into their powders and thus to make their consolidation at reduced temperatures.
本会記事
feedback
Top