Journal of the Japan Society of Powder and Powder Metallurgy
Online ISSN : 1880-9014
Print ISSN : 0532-8799
ISSN-L : 0532-8799
Volume 64, Issue 1
January
Displaying 1-6 of 6 articles from this issue
Paper
Memorial Lecture of JSPM Award
  • Kei AMEYAMA, Mie OTA
    2017 Volume 64 Issue 1 Pages 3-10
    Published: January 15, 2017
    Released on J-STAGE: February 09, 2017
    JOURNAL OPEN ACCESS

    Harmonic structure has three dimensional gradient microstructure. The harmonic structure has a heterogeneous microstructure consisting of bimodal grain size together with a controlled and specific topological distribution of fine and coarse grains. In other words, the harmonic structure is heterogeneous on micro- but homogeneous on macro-scales. The harmonic structure design has been applied to structural metallic materials, such as ferrous and non-ferrous materials, via a powder metallurgy route consisting of controlled severe plastic deformation of the corresponding powder and subsequent sintering process. At a macro-scale, the harmonic structure materials exhibited significantly better combination of strength and ductility, as compared to their homogeneous microstructure counterparts. This behavior was essentially related to the ability of the harmonic structure to promote the uniform distribution of strain during plastic deformation, leading to improved mechanical properties by avoiding or delaying localized plastic instability. In addition, the harmonic structure materials also showed many unique deformation behaviors.

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Paper
  • Zhi-yu XIAO, Yu-heng LU, Xiao LIU, Hang-jian GUAN
    2017 Volume 64 Issue 1 Pages 11-16
    Published: January 15, 2017
    Released on J-STAGE: February 09, 2017
    JOURNAL OPEN ACCESS

    The present work studied the ultrasonic fatigue fracture of the partially pre-alloyed Fe-Cu-Mn-C powder metallurgy steel fabricated by die-wall lubricated warm compaction. The microstructure and ultrasonic fatigue fracture behaviour were analyzed. A mathematical model was established to solve the fatigue crack growth process. Results indicate that the Fe-2Cu-0.5Mn-1C sintered material has good mechanial properties. The fatigue crack initiates at large pore cluster near the surface of sample, and the ultrasonic fatigue striations have been observed near crack source area. The crack source area is divided into several small regions: the micro fatigue source area, crack growth area and fast fracture area. In addition, if the material breaks at 107 times of cycles loading in fatigue tests, the crack stabe growth stage accounts for about 8.3×105 cycles, which is only a small part of the whole ultrasonic fatigue fracture process. The cycle times of crack stabe growth stage is inverse proportion to the square of the stress.

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  • Masayuki TAKADA, Hideaki MATSUBARA, Yoshihiro KAWAGISHI
    2017 Volume 64 Issue 1 Pages 17-22
    Published: January 15, 2017
    Released on J-STAGE: February 09, 2017
    JOURNAL OPEN ACCESS

    Wire drawing dies and specimens of WC-Co cemented carbides containing TaNbC or Cr3C2 were fabricated by hot isostatic press (HIP) treatment at 1633 K in 40 MPa Ar and by anneal treatment 1593 K in vacuum. The lifetime of steel code wire drawing were evaluated for the dies and mechanical properties such as hardness, transverse-rupture strength and fracture toughness were examined for the specimens. It is noted that the lifetime of drawing die was remarkably improved by the anneal treatment for both of TaNbC and Cr3C2 containing WC-Co cemented carbides. The TaNbC containing alloys showed longer lifetime than the Cr3C2 containing alloys. The lifetime of drawing die had weak relationship to hardness, but seemed to have no correlation with strength and toughness. The remarkable improvement of drawing die lifetime by the annealing treatment after HIP and the longer lifetime for TaNbC containing alloys can be understood from the viewpoint of adhesion strength between WC and Co phase affected by alloy content and heat treatment of cemented carbides.

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  • Shunsuke MURAI, Ryosuke KAMAKURA, Koji FUJITA, Yohei DAIDO, Katsuhisa ...
    2017 Volume 64 Issue 1 Pages 23-27
    Published: January 15, 2017
    Released on J-STAGE: February 09, 2017
    JOURNAL OPEN ACCESS

    We have fabricated highly crystallized thin films of niobium-doped anatase type titania (Ti1−xNbxO2) to examine the relationship between the electronic transport properties and the plasmonic response. Ti1−xNbxO2 thin films were epitaxially grown on LaTiO3 substrates by using pulsed laser deposition. Attenuated total reflectance spectra in the infrared (IR) region measured using the Otto configuration show a dip for p-polarized light, corresponding to an excitation of surface plasmon polaritons. The IR reflectivity data can be well reproduced by the theoretical calculation based on the Fresnel model, in which the dielectric function of Ti1−xNbxO2 can be modeled by the combination of a Lorentz term and a Drude term. The real part of dielectric function for Ti1−xNbxO2 (x = 0.03) is negative at the wavelengths longer than 2.78 μm in the IR region.

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