粉体および粉末冶金
Online ISSN : 1880-9014
Print ISSN : 0532-8799
ISSN-L : 0532-8799
56 巻, 11 号
November
選択された号の論文の11件中1~11を表示しています
研究
研究速報
研究
  • 東 泰助, 井上 誠, 小野木 伯薫, 横田 勝, 村田 安規, 中平 敦
    2009 年 56 巻 11 号 p. 661-667
    発行日: 2009年
    公開日: 2009/12/09
    ジャーナル オープンアクセス
    This study focuses on Ag-Cu-Sn ternary alloys used as brazing filler metals. These alloys are known to have a high wettability and a low melting temperature. However, the alloys become brittle by the addition of large amounts of Sn. In this study, we investigated the brazing characteristics and the mechanical properties of Ag-Cu-Sn ternary alloys that contain Sn in the range of 15 to 30 wt.% Sn, which have not been reported until now. 47.5 wt.% Ag-25.5 wt.% Cu-27.0 wt.% Sn alloy was compatible ratio with low melting temperature and high wettability. However the alloy was very brittle because of the existence of Cu3Sn. This material is known as hard and brittle intermetallic compounds. We added Ni to the alloy to improve the brittleness. 1 wt.% Ni addition improved its rupture strain significantly. It is suggested that the good mechanical properties are derived from production of (Cu, Ni)3Sn intermetallic compounds and grain coarsening.
  • 和田 任弘, 中西 順
    2009 年 56 巻 11 号 p. 668-671
    発行日: 2009年
    公開日: 2009/12/09
    ジャーナル オープンアクセス
    In turning operations, it is effective to use a larger corner radius or a lower feed rate to obtain a good machined surface. However, turning at lower feed rates decreases productivity and it has a negative influence on the turning operation because of the continuous chip. In turning of a shaft having a step of specified corner R, it is important whether the corner radius of the turning insert is the same as specified corner R or lower than it. A turning tool with a large corner radius cannot adapt to cutting a shaft having a step of specified corner R. In this study, the surface roughness, cutting force, and tool wear were experimentally investigated in order to clarify the cutting performance of the turning insert having an arc-shaped finishing edge formed at the point of intersection between the corner radius and the end cutting edge. Work piece material SKD11 was turned with two kinds of turning inserts that had different radii of the arc-shaped finishing edge.
    The main results obtained are as follows. (1) The machined surface of the insert having an arc-shaped finish edge was better than that of the normal insert. (2) The wear progress of the insert having an arc-shaped finish edge was slightly slower than that of the normal insert. (3) The cutting force of the insert having an arc-shaped finish edge was almost the same as that of the normal insert.
  • 和田 任弘, 岩本 晃二
    2009 年 56 巻 11 号 p. 672-676
    発行日: 2009年
    公開日: 2009/12/09
    ジャーナル オープンアクセス
    Polycrystalline cubic boron nitride compact (cBN) tools are widely used for cutting hardened steel, due to their higher hardness and higher thermal conductivity. However, in higher feed rate cutting, fracture of the cBN cutting tool occurs easily because it has poor fracture toughness. Coated cemented carbide tools, which have good fracture toughness and wear resistance, seem to be effective tool materials in the higher feed rate cutting of hardened steel.
    In this study, hardened steel (SKD11, 60HRC) was cut with three physical vapor deposition (PVD) coated cemented carbide tools in order to investigate effective tool materials for cutting hardened steel at high feed rate cutting. The coating films used were (Ti, Al)N, (Ti, W, Si)N and (Ti, W)N/(Ti, W, Si)N coating film.
    The following results were obtained: (1) In turning hardened steel, the wear progress of the (Ti, W)N/(Ti, W, Si)N coated tool was slower than that of the (Ti, Al)N or (Ti, W, Si)N coated tool. (2) In milling hardened steel, the (Ti, W)N/(Ti, W, Si)N coated cemented carbide was an effective tool material for high speed cutting below a cutting speed of 2.5 m/s.
特集:金属ガラスの最近の研究
総報
研究
  • 松原 英一郎
    2009 年 56 巻 11 号 p. 679-682
    発行日: 2009年
    公開日: 2009/12/09
    ジャーナル オープンアクセス
    Structural analyses of conventional amorphous alloy Zr-Ni and metallic glass Zr-Al-Ni have been studied in combination of measurements by neutron diffraction and x-ray diffraction, and their structural models have been built with the reverse-Monte Carlo method by Fukunage et al. The structural models provided us some important results. Firstly, the density of icosahedron-like polyhedra increases in the metallic glass in comparison with the conventional amorphous alloy. Secondly, the structures of amorphous alloys which include the conventional amorphous alloys as well as the metallic glasses would be characterized by the three distinct polyhedra, that is, the icosahedron-like polyhedra (I), the trigonal prism-like polyhedra (P) and the polyhedra (W) which do not belong to either. As mentioned above, the ‘ I ’ polyhedra are commonly found in the metallic glasses. The ‘ P ’ polyhedra resemble the local atomic configurations of the primary crystalline phase precipitated in the amorphous matrix. Thus, the glass formability has been determined by the competition between ‘ I ’ and ‘ P ’. The ‘ W ’ polyhedra appear in the metallic glass with increase in the fraction of ‘ I ’. They show large coordination numbers more than 13. Taking into consideration of the atomic sizes of the constituents, W is a polyhedron consisting of weakly bonded atoms in comparison with I and P. A spatial distribution of W controls the inhomogeneity of the metallic glass and is profoundly related with the fragility and other physical properties.
解説
  • 五十嵐 貴教, 中島 浩二, 石川 智仁, 杉山 雅治, 福本 昌宏, 木村 久道, 牧野 彰宏, 井上 明久
    2009 年 56 巻 11 号 p. 683-692
    発行日: 2009年
    公開日: 2009/12/09
    ジャーナル オープンアクセス
    Glassy alloy is a promising material for a wide range application because of its superior mechanical and chemical characteristics. If the forming technology, which realizes a glassy alloy coating on the surface of various products, was established, its application will be widely expanded.
    In this description, first, we described to produce the glassy phase coating by using Fe43Cr16Mo16C15B10 glassy alloy powder and HVOF (High Velocity Oxy-Fuel) spraying process. And it was coated onto the substrate such as stainless-steel, aluminum-alloy and magnesium-alloy. As a result, we confirmed it possible to produce them on each substrate.
    Second, to examine the formation process to attain the glassy phase coating, we carried out experiment of coating, using Fe43Cr16Mo16C15B10 glassy alloy powder and crystallized powders of it, and two different thermal-spraying-equipment (HVOF: High Velocity Oxy-Fuel, APS: Atmospheric Plasma Spraying). As a result, in HVOF, most glassy alloy particles were estimated to coat with the glassy phase due to its low viscosity flowing in super-cooled liquid state without melting. And we also confirmed it possible to get the glassy phase coating extremely stably in HVOF, as compare with coating in APS that almost particles were completely melted.
    As the examples to practice application, we introduced "erosion resistance against lead-free solder", "coating for metal bipolar plate" and "soft magnetic coating".
研究
受賞記念講演
  • 木村 久道, 笹森 賢一郎, 井上 明久
    2009 年 56 巻 11 号 p. 697-708
    発行日: 2009年
    公開日: 2009/12/09
    ジャーナル オープンアクセス
    We developed aluminum-based alloys consisting of amorphous, quasicrystalline, nano quasicrystalline plus fcc-Al, nano amorphous plus fcc-Al and glassy phases by a single-roller melt spinning method and a powder-metallurgy processing and examined their structure, thermal, electrical and mechanical properties. The high-pressure gas atomization technique was also used to prepare various aluminum-based alloy powders. Amorphous Al-M-Ni (M: Si, Ge) alloys have good bending ductility and glassy Al-Ln-Ni (Ln: Y, Ce) alloys exhibit a distinct supercooled liquid region. Besides, amorphous or glassy Al-Y-Ni-Co-Sc alloys have the highest strength reported ever before. We also found high strength alloys as Al-Cr-Ce-Co alloys with nano quasicrystalline particles dispersed in fcc-Al phase and Al-M-Fe (M: Ti, V) alloys with nano amorphous particles dispersed in fcc-Al phase. Further, by using the powder metallurgy method, we developed Al-V-Fe and Al-Fe-Cr-Ti alloy rods consisting of quasicrystalline particle dispersed in fcc-Al phase. These aluminum-based alloy rods show high strength, high elevated temperature strength and excellent abrasion resistance.
エラータ (Vol.56, No.9)
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