Journal of the Japan Society of Powder and Powder Metallurgy
Online ISSN : 1880-9014
Print ISSN : 0532-8799
ISSN-L : 0532-8799
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Volume 58, Issue 7
July
Displaying 1-11 of 11 articles from this issue
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Paper
Paper
  • Wettability, Interfacial Reaction and Joint Strength between Low Melting Ag Based Brazing Alloy and Some Industrial Metal Plates
    Makoto Inoue, Taisuke Higashi, Takamasa Onoki, Masaru Yokota, Yasunori ...
    2011 Volume 58 Issue 7 Pages 407-411
    Published: 2011
    Released on J-STAGE: October 12, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.407
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    We have developed the Ag-Cu-Sn-Ni quaternary brazing filler metal having a low melting point, a high strength and a high ductility. Then, we produced wire saws composed of Ni-coated SUS304 wires, on which diamond abrasives are fixed with this brazing filler metal. We tried to slice the Si ingots using this wire saw. Good results were obtained for the application to the production of silicon wafers for solar cells. Accordingly, we focused on the basic experiments for further performance of the fixed abrasive diamond wire saws, leading to low cost of slicing technique of hard materials such as silicon and sapphire. In particular, we examined wettability, interfacial reaction and joint strength between Ag-Cu-Sn-Ni quaternary brazing filler metal and industrial metal plates such as Cu, Ni or flux coated SUS304.
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  • Interpretation of Superconductivity and its Critical Temperature (Tc) in Elemental Substances by Valence Electron Parameters
    Yukio Makino, Kazuyoshi Yoshimura
    2011 Volume 58 Issue 7 Pages 412-416
    Published: 2011
    Released on J-STAGE: October 12, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.412
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    It has been tried to interpret the superconductivity and its critical temperature (Tc ) in the elemental substances by the orbital electronegativity of the s electron, (Z/r (s))1/2, which is defined by the pseudopotential radius of the s electron, r (s), and the valence, Z. Dependence of critical temperature (Tc ) on (Z/r (s))1/2 showed a convex curve with a maximum around (Z/r (s))1/2=2.0, except for several substances and it is found that the elemental substances with higher Tc such as Nb and Pb have a (Z/r (s) )1/2 value close to the threshold one corresponding to the change from metal to semiconductor. Many exceptional substances can be plotted close to the convex curve by considering the effect of the p electron or by changing the cohesion state from bulk to film, suggesting the increase of Tc value due to the increase of s- and/or p-characters, though the critical temperature for metastable elemental substances is not completely explained by the orbital electronegativity of the s electron.
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  • Two-dimensional Mapping of Superconducting Materials by Valence Electron Parameters
    Yukio Makino, Kazuyoshi Yoshimura
    2011 Volume 58 Issue 7 Pages 417-422
    Published: 2011
    Released on J-STAGE: October 12, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.417
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    Two dimensional mappings on superconductive elements A and AB compounds are constructed by using the valence electron parameters (the difference between pseudopotential radii (r (s), r (p) and r (d)) of s and p electrons or of s and d electrons, Δ(sp) or Δ(sd), and the orbital electronegativity of s electron, χ(s)=(Z/r (s))1/2, where Z is valence) as the coordinates. From the relation of band gap against χ(s), the change of metal to semiconductor in sp-bonded elemental substances occurs at the threshold value of (Z/r (s))1/2=2.098. It is found that the boundary for superconductivity in sp-bonded elemental substances and AB compounds appears around (Z/r (s))1/2≈2.3. On the other hand, superconductivity appears in the region with higher (Z/r (s))1/2 value in the transition metals and AB compounds containing transition metals. Lower limit in the abscissa scale is observed around (Z/r (s))1/2=1.3, suggesting the limitation due to electron density in metallic substances and AB compounds. Non-superconducting late 3d transition elements are clearly divided by a polynomial curve. Non-superconducting sp-bonded AB compounds are well separately placed in the region with higher (Z/r (s))1/2 value than 2.3 and lower Δ(sp) value than 0.150.
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  • Pulsed Current Welding for Fe-V-Al Alloy Spherical Particles and Their Mechanical Property
    Kenta Takagi, Kimihiro Ozaki, Masashi Mikami, Keizo Kobayashi, Naohide ...
    2011 Volume 58 Issue 7 Pages 423-428
    Published: 2011
    Released on J-STAGE: October 12, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.423
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    An interparticle pulsed current welding was conducted for spherical particles of Fe-V-Al alloy with a diameter of 500 μm. The particles were successfully welded by the pulsed current with the voltage of ∼4 V and the width of 400 μsec. The particles were completely joined such that the welded interface was not recognized. In addition, adjustment of the input electric energy allowed the precise control of the welding area and the depth of interparticle penetration. The melted volumes during the welding were estimated to be only several % with respect to the total volume of the particle. These results suggested that the pulsed current welding was available to the interparticle bonding method for particle assembly. As a result of the excellent welding, the average tensile strength of the welded particles was 250 MPa, which was enough high for a particle joint.
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Special Issue: Progress and Research Problems of Hard Materials Part I
Summarization
Paper
  • Some Properties and Cutting Performance of WC-βt-Ti(C, N)-Co Alloys
    Yukihiro Hosoda, Kusuhiko Sakagami, Tsutomu Yamamoto
    2011 Volume 58 Issue 7 Pages 431-435
    Published: 2011
    Released on J-STAGE: October 12, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.431
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    In order to evaluate mechanical and thermal properties of WC-βt-Ti(C,N)-Co alloys consisting of four phases, the effects of additional Ti(C, N) content on mechanical and thermal properties of the alloys were mainly investigated. Moreover, cutting performance of the alloys in face milling was investigated comparing with the case of WC-βt-Co alloys with the same level of hardness. The results obtained were as follows; (1) The hardness increased with increasing Ti(C, N) content in the alloy. On the other hand, the fracture toughness and elastic modulus and thermal conductivity decreased with increasing Ti(C, N) content in the alloy. In other words, these changes of mechanical and thermal properties were considered to be mainly due to area proportion of WC phase in the microstructure of the alloy. However, the transverse-rupture strength scarcely changed by Ti(C, N) content in the alloy because the size of fracture origin consisting of the aggregated βt was almost same with no relation to Ti(C, N) content. (2) The cutting performance of WC-βt-Ti(C, N)-Co alloys was remarkably superior to that of WC-βt-Co alloys in wear resistance and surface roughness.
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  • Fabrication of Porous Structured WC-Co Alloy Compacts by Indirect Laser Forming
    Hyungoo Kang, Tomoyuki Ishii, Fujio Tsumori, Hideshi Miura
    2011 Volume 58 Issue 7 Pages 436-441
    Published: 2011
    Released on J-STAGE: October 12, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.436
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    This study deals with manufacturing of porous structured WC-Co alloy compacts and the forming mechanism by indirect laser forming. In this process, added binder is melted and formed as designed shape by irradiated laser beam. Therefore, the effects of laser energy density on the relative density and forming mechanism were mainly investigated. As the results, the porosity of WC-Co alloy compacts could be controlled by laser energy density decided by scan rate, scan pitch and feedstock layer thickness. It was also found that remained binder amount play an important role in forming pores during liquid phase sintering in WC-Co alloy compacts. Finally, the smart porous structured WC-Co alloy compacts which own the dense surface layer and porous interior was manufactured by controlling the laser energy density.
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  • Simultaneous Sintering of Ti(C, N)-based Cermet and Cemented Carbide
    Hiroyuki Nakayama, Kimihiro Ozaki, Haruka Morishita, Keizo Kobayashi
    2011 Volume 58 Issue 7 Pages 442-446
    Published: 2011
    Released on J-STAGE: October 12, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.442
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    Layered compacts, which were composed of cemented carbide/cermet/cemented carbide layers, were sintered at 1673 K for 1.2 ks under vacuum. Compositions of cermet and cemented carbide layers were Ti(C, N)-30WC-5Mo2C-20Co (mass%) and WC-2TaC-6Co (mass%), respectively. These alloy powders were prepared by mechanical milling from Ti(C, N), WC, Mo2C, TaC and Co powders. The milling was carried out for 1.8 ks under Ar atmosphere.
    The cermet layer showed slightly different sintering behavior from the cemented carbide, thus slight residual compressive stress was detected in the cemented carbide layer. However, the compact was successfully sintered without delamination and rather showed the flat surfaces at the boundaries on the edge face. The solid solution composed of WC, TiC and TaC was observed at the interface between cermet and cemented carbide layers.
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  • Formation of (Ti, Mo)(C, N) Solid Solution by Additive Elements and Reactivity with Nickel
    Wataru Koike, Ai Momozawa, Takuya Fujima, Ken-ichi Takagi
    2011 Volume 58 Issue 7 Pages 447-451
    Published: 2011
    Released on J-STAGE: October 12, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.447
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    To investigate the possibility to form the solid solution of (Ti, Mo)(C, N) with B, Al and Si, powder mixtures of 5 at% of B, Al and Si added (Ti0.9Mo0.1)(C0.55N0.45) prepared from Ti(C0.5N0.5), Mo2C, TiB2, AlN and Si3N4 were heat treated at 2473 K for 2 h in N2. Moreover these powder mixtures were hot pressed at 2473 K at 40 MPa for 2 h in N2 to form sintered bodies. By using these powders and sintered bodies whether the added elements dissolved in (Ti, Mo)(C, N) or not was investigated by means of X ray diffraction (XRD) and micro structural observation. The reactivity of the sintered bodies with pure Ni heat treated at 1673 K for 1 h in Ar was also studied.
    As a result heat treated (Ti, Mo)(C, N) powders did not form solid solutions with added elements. On the other hand hot pressed sintered bodies dissolved some amount of B and Si and resulted in to form solid solutions but the sintered body did not dissolve any Al. The reaction layer thickness of B and Si added (Ti, Mo)(C, N) sintered bodies with Ni were similar to that of (Ti, Mo)(C, N) without any added elements. The Al added (Ti, Mo)(C, N) sintered body showed thinner reaction layer than B and Si added ones.
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