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 6
June
Displaying 1-17 of 17 articles from this issue
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Paper
Paper
  • Effects of Warm Compaction on Compressibility and Sinterability of Pure Magnesium Powder
    Taku Iwaoka, Mitsuru Nakamura
    2011 Volume 58 Issue 6 Pages 327-333
    Published: 2011
    Released on J-STAGE: July 15, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.327
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    Warm compaction is known as an efficient way to increase green density, which contributes to increase strength after sintering. In this study, the application of a warm compaction method to the pure magnesium powder was investigated. The compressibility and compaction behavior of pure magnesium powder compacted at various temperatures and pressures were measured. The porosity and ejection stress of the pure magnesium green compacts processed at 373 K under a pressure of 489 MPa were about 0.5 % and 1.4 MPa, respectively. It was found that sintered transverse rupture strength of the warm compacted specimens is higher than that of the cold compacted specimens. The difference in strength between cold and warm compacted specimens increased with increasing sintering temperature. The maximum difference was about 40 MPa. The increase of the sintered strength is considered to be due to the increase in contacting area among the powder particles promoted by the warm compaction. In conclusion, the experimental results showed that the warm compaction method is an effective method to compact a pure magnesium powder into near full density and therefore to increase the sintered strength.
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  • Elucidation of Formation Process of NiFe2O4 Ferrite Nano-crystalline Powder Synthesized by Sol-gel Auto-combustion Method
    Nobuyuki Hiratsuka, Kyohei Kono, Kenji Kamishima, Koichi Kakizaki, Yos ...
    2011 Volume 58 Issue 6 Pages 334-339
    Published: 2011
    Released on J-STAGE: July 15, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.334
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    Nano-crystalline NiFe2O4 (NF) powder was prepared by a sol-gel auto-combustion method. Its crystal structure, morphology, particle size and magnetic properties were investigated and the formation process of nano-crystalline NF was elucidated. The as-dried Ni-Fe precursor (Ni/Fe=0.5) was calcined in air at 200-800°C for 4 hours. γ-Fe2O3 powder was formed at about 210°C by the self-combustion of the gel, and was maintained at 200-400°C. Single-phase NF sample was obtained by being calcined at 600-800°C. The NF particles were of nano-crystalline with crystallite diameters of 68.2-94.3 nm which were determined by the use of Scherrer equation for XRD peak broadening and the observation of TEM images. The sample calcined at 200°C had a magnetization value of 44 emu/g, which was lower than that of bulk γ-Fe2O3 (70 emu/g) because of a lot of vacancies at octahedral sites. Magnetization was increased gradually with increasing calcination temperature, and reached to the maximum value of 46 emu/g for the samples calcined at 700 and 800°C, which was in agreement with the magnetization of the bulk NF sample. Coercivity was decreased with increasing calcination temperature.
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Special Issue: Application of High Performance and High Characteristics Sintering Material to Auto Parts
Summarization
Paper
  • Environment-conscious Cu Free Sintered Steels (Report 2) Effect of Sintering Temperature
    Toshitake Miyake, Nobuhiko Matsumoto, Mikio Kondoh, Kimihiko Ando
    2011 Volume 58 Issue 6 Pages 343-349
    Published: 2011
    Released on J-STAGE: July 15, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.343
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    Fe-Cu-C sintered steels are widely used for automobile parts. In case of reusing these sintered steels as the raw materials of wrought steels, it becomes to be a problem that Cu contamination deteriorates hot workability of wrought steels. In order to recycle the scrapped sintered steels, Cu free sintered steels are strongly required. We developed new Fe-Mn-Si-C sintered steel as a candidate material to the conventional Fe-Cu-C sintered steels. The developed sintered steel shows superior mechanical properties compared with the conventional sintered steels by adding Mn and Si elements to the Fe-Mn-Si ternary master alloy (FeMS) powder.
    In this study, the influence of sintering temperature and also particle size of FeMS powders on the mechanical properties of the new Fe-Mn-Si-C sintered steels were investigated. The tensile strength is improved by not only rising sintering temperature and also adding the fine FeMS powder. In particular, this improvement is considered to be resulted from the microstructural changes as follows. The addition of the fine FeMS powder works to increase amount of the fine pearlite phase in whole of the microstructure and also inhibit the precipitation of the martensite phase at the Mn and Si enriched regions.
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  • Effect of Mezzo-Heterogeneous Microstructure and Rolling on the Tooth Root Bending Fatigue Properties of Sintered Ni Alloy Steel Gears
    Terukazu Tokuoka, Toru Yamamoto, Kentaro Kudo, Fujio Tsumori, Hideshi ...
    2011 Volume 58 Issue 6 Pages 350-354
    Published: 2011
    Released on J-STAGE: July 15, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.350
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    This study aims at reducing costs of high load gear manufacturing, and substituting P/M gears for conventional wrought steel gears. In order to improve the fatigue strength of P/M gears, we focused on the rolling and the high performance sintered and heat treated 4600 series alloy steels with mezzo-heterogeneous microstructure which were made from the mixed elemental powders. The fatigue strength was determined by single tooth root bending fatigue test machine, and the effect of mezzo-heterogeneous microstructure and rolling on the fatigue strength was mainly investigated. The endurance limit at N=3.0×106 of the 500 μm rolled 6 % Ni alloy steel gear compact showed 950 MPa which value is about 2/3 of the case hardened wrought steel (SCM415) gears. However, the endurance limit of rolled and heat treated gear compact showed lower value (630 MPa) as compared to as-rolled gear compact. This seems to be due to the decreasing the compressive residual stress by heat treatment and unfavorable mezzo-heterogeneous microstructures.
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  • Fatigue Properties of Ti Alloy Compacts by Metal Injection Molding - Part1
    Munehiro Noda, Toshiko Osada, Fujio Tsumori, Hideshi Miura
    2011 Volume 58 Issue 6 Pages 355-360
    Published: 2011
    Released on J-STAGE: July 15, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.355
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    Titanium and its alloy have many advantages such as high specific strength, excellent corrosion resistance and biocompatibility. However, it is not easy to fabricate the complex shaped parts using titanium alloy because of their poor machinability and workability. Metal injection molding (MIM) process is hoped to be a suitable technique to fabricate three dimensional complicated parts of titanium and its alloy. Although the static mechanical properties of injection molded titanium alloy compacts have been studied, there are few reports regarding the dynamic fracture characteristics. In this study, pure titanium and Ti-6Al-4V alloy compacts are fabricated by MIM process and the effects of sintering conditions on the fatigue properties are mainly investigated. By optimum sintering conditions, over 95 % of sintered densities were obtained and the fatigue endurance was 164 MPa for pure titanium and 230 MPa for Ti-6Al-4V alloy, respectively.
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  • Fabrication of Super-Elastic Ti-10V-2Fe-3Al Alloy Compacts by MIM Process
    Kensaku Sagara, Minoru Nishida, Hyungoo Kang, Fujio Tsumori, Hideshi M ...
    2011 Volume 58 Issue 6 Pages 361-366
    Published: 2011
    Released on J-STAGE: July 15, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.361
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    Titanium alloys have been used especially as aerospace, medical and dental materials because of their excellent attributes of high corrosion resistance and high specific strength. A Ti-10V-2Fe-3Al is one of β-titanium alloy and it shows super-elasticity. In this study, the fabrication of super-elastic Ti-10V-2Fe-3Al alloy compacts by metal injection molding which is one of near net shape forming of powders was investigated using mixed elemental and alloy powders. Under the optimized MIM process condition, nearly full density (97∼98 %) was obtained and the tensile properties of strength and elongation were 1000∼1050 MPa and around 5 %, respectively. Moreover, after solution treatment and aging, the compacts with alloy powder showed clearly super-elasticity.
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Review
  • Development of the Encapsulated Thermoelectric Modules and their Application to the Industrial Waste Heat
    Mitsuru Kambe, Takahiro Jinushi, Zenzo Ishijima
    2011 Volume 58 Issue 6 Pages 367-373
    Published: 2011
    Released on J-STAGE: July 15, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.367
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    An encapsulated thermoelectric (TE) module consists of a vacuum tight stainless steel container of 55×50×11 mm in which a SiGe or BiTe TE module is encapsulated. This situation enables maximum performance and durability because (1) the thermal expansion mismatch between the hot and cold sides of the container can be accommodated by a sliding sheet in the container, (2) the TE module inside is always kept in a vacuum environment, therefore no oxidation can occur, and (3) the difference in pressure between the inside and outside of the container reduces thermal contact resistance inside the container. The encapsulated module could be applied to various environments and features maximum TE power with minimum installation cost. An attempt has been made to adopt the encapsulated TE modules to make use of waste heat of the powder metallurgy furnace. Heat transfer analysis and cost evaluation of the system have been made. Demonstration of the encapsulated TE module performance at the powder metallurgy furnace has been conducted and proven 3000 hr operation.
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Paper
  • Thermoelectric Properties of Double Perovskite (Sr, Ba)2(Fe, Mn)(Mo, V)O6
    Ayaka Oba, Kenji Kamishima, Koichi Kakizaki, Yoshihiro Ishimaru, Masam ...
    2011 Volume 58 Issue 6 Pages 374-379
    Published: 2011
    Released on J-STAGE: July 15, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.374
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    Sr2FeMo1-xVxO6 (x=0-1.0), Sr2-yBayFeMo0.8V0.2O6 (y=0-1.0) and Sr1.4Ba0.6Fe1-zMnzMo0.8V0.2O6 (z=0-1.0) samples were prepared by using a conventional ceramic method. The crystal structure, bulk density and resistivity of the samples were investigated. The thermoelectric properties of Sr2-yBayFe1-zMnzMo0.8V0.2O6 were examined. In the X-ray diffraction patterns of the samples sintered at 1200°C, the double perovskite phase was confirmed. Sr1.4Ba0.6FeMo0.8V0.2O6 sample had the highest conductivity in Sr2-yBayFe1-zMnzMo0.8V0.2O6 samples. The Seebeck coefficients S of Sr2-yBayFe1-zMnzMo0.8V0.2O6 are negative for 100°C < T < 700°C so that these samples are n-type semiconductors. In particular, the power factor S2σ of Sr2-yBayFe1-zMnzMo0.8V0.2O6 samples increased with increasing Ba and Mn doping up to y=0.6 and z=0.2. The power factor S2σ of Sr1.4Ba0.6Fe0.8Mn0.2Mo0.8V0.2O6 showed the largest value of 83.2 mW/K2m.
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JSPM Announcements
Retracted Publication
  • Retracted Publication:Fe-Based Glassy Magnetic Cores Prepared by Spark Plasma Sintering Glassy Alloy Powders
    Baolong Shen, Akihisa Inoue
    2011 Volume 58 Issue 6 Pages 403
    Published: 2011
    Released on J-STAGE: July 15, 2011
    DOIhttps://doi.org/10.2497/jjspm.58.403
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    Retracted Publication

    "Journal of Japan Society of Powder and Powder Metallurgy", Chairman of Editorial Board, Kazuyoshi Yoshimura

    Editorial Board of "Journal of Japan Society of Powder and Powder Metallurgy" has found that the paper #1 below (published in Vol. 50, No. 9 (2003) pp. 680-686) seriously resembles and duplicates the previously published paper #2 in J. Materials Research. Consequently, the editorial board has reached a serious decision that the paper #1 should be retracted due to the academic moral issue.
    This treatment has been conducted since the editorial board did not notice the duplication through and after refereeing #1 because the authors did not confess the situation that they submitted #1 in the midst of refereeing #2 in J. Materials Research.

    #1 "Fe-Based Glassy Magnetic Cores Prepared by Spark Plasma Sintering Glassy Alloy Powders", Baolong Shen and Akihisa Inoue, Journal of the Japan Society of Powder and Powder Metallurgy, Vol.50, No.9 (2003) 680-686. ( Received May 2, 2003 )

    #2 "Fabrication of large-size Fe-based glassy cores with good soft magnetic properties by spark plasma sintering", Baolong Shen and A. Inoue, Journal of Materials Research, Vol.18, No.9 (2003) 2115-2121. ( Received 27 April, 2003, accepted 10 June, 2003 )
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