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Volume 41, Issue 7
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[in Japanese]1994 Volume 41 Issue 7 Pages 758
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDownload PDF (80K) -
Akira Sakamoto1994 Volume 41 Issue 7 Pages 759-765
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe current status of research and development on titanium aluminide matrix composites is outlined. Continuous silicon carbide filament reinforced alpha-2 titanium aluminides have been proven to be promising as the high specific strength structural materials in the 600 to 1000°C range, while more extensive work is required before the gamma alloy matrix composites become viable structural materials.View full abstractDownload PDF (3523K) -
Ryuichi Yamashita, Kenzo Fukaura, Hisakichi Sunada, Nobumitsu Takase, ...1994 Volume 41 Issue 7 Pages 766-769
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSAl2O3 fiber and/or particle reinforced Ni3At matrix composites were produced by elemental powder metallurgy, The high temperature tensile properties of the composites were investigated in the connection with microstructures. The results were summaried as follows;
The distribution of short Al2O3 fiber in Ni3Al matrix was more uniform than that of long Al2O3 fiber. The grain growth of matrices in the composites was suppressed by adding A1203 particles. The yield strength of every composites increased with increasing temperature to the peak temperature about 800K and then it degraded abruptly above that temperature. The complex addition of both short fiber and particle was the most effective to improve high temperature tensile properties.View full abstractDownload PDF (3788K) -
Sennosuke Takahashi1994 Volume 41 Issue 7 Pages 770-773
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSYield strength of titanium carbide particle dispersion strengthened nickel alloys were measured in the temperature range of 800°to 1100°C by use of compression tests. Samples were prepared through the melting-pressing and HIP treatments from the hot pressed materials.
The yield strength of HIP samples lineally increased with increase of titanium carbide content from 10 to 40%, but that of melting-pressing sample showed maximum near 30% of titanium carbide.
It was found from SEM observations that titanium carbide particles grew and turned into spherical shapes due to melting treatment.View full abstractDownload PDF (1350K) -
Kenzo Fukaura, Yasuhiro Hashimoto, Kazuya Fukuda, Hisashi Izumi, Hisak ...1994 Volume 41 Issue 7 Pages 774-779
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSRecently, various kinds of oxide whisker have been developed which are much cheaper than SiC or Si3N4 whiskers. These oxide whiskers may be available for fillers which reinforce metal matrix composites. We have already studied on the microstructural change at interface and tensile properties of oxide whiskers reinforced aluminum and aluminum alloy matrices composites. The results were that aluminum borate whisker reinforced composite revealed the most superior specific strength and the most stable microstructure of all. The aim of this study was to make clear the fatigue behavior of the composite comparing with SiC whisker reinforced one. Fatigue limits were increased with volume fraction like that of SiC whisker reinforced one, however, the dependence of whisker volume fraction on fatigue strength was weaker than that for SiC whisker reinforced one. This difference was considered to be due to smaller aspect ratio of aluminum borate whisker which decreased more than that of SiC whisker with increasing whisker volume fraction.View full abstractDownload PDF (3278K) -
Naohisa Nishino, Shin-ichi Towata1994 Volume 41 Issue 7 Pages 780-783
Published: July 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSAluminum borate whisker reinforced Al-Cu and Al-Cu-Mg alloy matrix composites were fabricated by a squeeze casting. Aging behavior of the composites was investigated by means of hardness measurement and differential scanning calorimetry (DSC). It was found that there was an accelerated aging kinetics in the composites compared with the unreinforced Al alloys. DSC measurements indicated that the aging kinetics of the composite and unreinforced Al alloy were identical for Al-Cu matrix, but they were extremely different for AI-Cu-Mg alloy matrix. In the AI-Cu-Mg alloy matrix composite, magnesium in the matrix was consumed by reacting with the whiskers. As the results, the aging behavior of the Al-Cu-Mg alloy matrix composite was similar to that of the Al-Cu alloy matrix composite.View full abstractDownload PDF (1256K) -
Ichitaro Takagi, Keijiro Terashita, Kei Miyanami1994 Volume 41 Issue 7 Pages 784-789
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn the design of ceramic composites, composition is usually determined by mechanical properties. However, in order to promote industrialization of the composites, it is very important to consider the handling of particles. In this study, first composite particles with high dispersion of two components were formed by spray-drying of slurry, which rate of components was varied. And then we pressed and sintered to obtain A1203-Zr02 composite. If the rate of Zr02 was relative high to give the composites tenacity, particles became light and rough, and ability of packing into mold remarkably went down. As a result, its handling must be harder, and then shrinkage increased in sintering. Besides the dispersion state of each component on the surface of sintered body could be quantitatively evaluated by X-ray elementary analysis.View full abstractDownload PDF (2808K) -
Hiroshi Watanabe, Ken Hirota, Osamu Yamaguchi, Kideki Kume, Suguru Ina ...1994 Volume 41 Issue 7 Pages 790-794
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSMetastable t-ZrO2 solid solutions with the composition of ZrO2/Y2O3/Al2O3=(74.25-71.25)/(0.75-3.75)/25 mol% crystallize at 780°-860°C from amorphous materials prepared by the simultaneous hydrolysis of zirconium, yttrium and aluminum acetylacetonates. Two kinds of materials are fabricated by hot isostatic pressing for 1 hat 1130°and 1230°C under 196 MPa: (i) perfect ZrO2 solid solution ceramics and (ii) composites of ZrO2 solid solution and α-Al2O3. Mechanical properties are examined in connection with the microstructures and t/m ratios.View full abstractDownload PDF (2626K) -
Tomoaki Kamiyama, Ying Wang, Kenji Suzuki, Masaki Shibuya, Takemi Yama ...1994 Volume 41 Issue 7 Pages 795-798
Published: July 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSSi-Ti-C-O fiber, which is prepared by pyrolysing melt-spun polytitanocarbosilane fibers at the temperature higher than 1000°C (Yajima method), has a high tensile strength. The structural evolution of Si-Ti-C-O fibers by pyrolysis temperature between 500° and 1400°C was investigated by small-angle X-ray scattering (SAXS). The SAXS intensities of the Si-Ti-C-O fibers pyrolysed at higher than 1000°C obey the Porod law at the scattering vector higher than about 4 nm-1, while the Porod-decay cannot be observed in the SAXS intensities of the fibers pyrolysed below 800°C. The radii of gyration obtained from the SAXS intensities increase from 0.48 to 1.05 nm with increase in the pyrolysis temperature from 1000° to 1400°C. A conversion from organometallic polymer "polytitanocarbosilane" to ceramics "Si-Ti-C-O amorphous fiber" including β-SiC nano-clusters occurs drastically at the pyrolytic temperature of about 1000°C.View full abstractDownload PDF (228K) -
Toshio Shimoo, Jun-ichi Nishida, Yoshiro Katase, Kiyohito Okamura1994 Volume 41 Issue 7 Pages 799-804
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn relation to the synthesis of the reinforced ceramic matrix composites, the pyrolysis mechanism of Si-C-O fiber (Nicalon NL200) in Si3N4 powder was studied by TG, XRD and tensile test. At lower temperatures, the pyrolytic rates were unaffected by the presence of Si3N4 powder. The pyrolysis proceeded much more slowly in N2 than in Ar. The pyrolysis was controlled by either the growth of $-SiC crystallites (in Ar) or the diffusion of the pyrolytic gases (SiO and CO) through the nitrided case of Nicalon (in N2). At higher temperatures, the packing of Si3N4 powder retarded the pyrolysis in both Ar and N2. The rate-determining step is considered to be the gaseous diffusion through the interparticle pores within the powder.View full abstractDownload PDF (303K) -
Toshio Shimoo, Jun-ichi Nishida, Yoshiro Katase, Kiyohito Okamura1994 Volume 41 Issue 7 Pages 805-810
Published: July 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSThe pyrolytic behaviors of Si-C-O fiber (Nicalon) and Si-Ti-C-O fiber (Tyranno) in N2 or Ar have been studied by TG, XRD and tensile test. At 1973K, the fibers pyrolyzed severely in both N2 and Ar. Below 1923K, the fibers pyrolyzed more slowly in N2 than in Ar. Consequently, in N2, the crystalization to β-SiC was retarded and the tensile strength was held at a high level. The nitrogen bearing layer was formed on the surface of the fibers heated in N2. This layer is considered to restrict the escape of the pyrolytic gases (SiO and CO) from the core.View full abstractDownload PDF (312K) -
Hideto Yoshida, Noboru Miyata, Kazunari Naito, Chitake Yamagishi1994 Volume 41 Issue 7 Pages 811-816
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn this paper, the methods of improving mechancal properties of SiC composites reinforced with unidirectionally oriented carbon fibers (Ct/SiC) were discussed. Fibrous preform of Ct/SiC composite was formed by filament winding and consolidated by hot pressing. Mechancal properties of Ct/SiC depended strongly on characteristics of carbonfibers, fabrication conditions and fiber/matrix interfacial properties. For obtaining the excellent Ct/SiC composite, it is important to choose carbon fibers with high durability under the processing, and it is necessary to fabricate the Ct/SiC composite with high density and appropriate fiber/matrix interfacial properties.View full abstractDownload PDF (2606K) -
Influence of Specimen Size and Span/Depth RatioHideto Yoshida, Kazunari Naito, Chitake Yamagishi1994 Volume 41 Issue 7 Pages 817-820
Published: July 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSIn this paper, bending strength and fracture behavior of carbon fiber reinforced silicon carbide matrix composites (Cf/SiC) was discussed. The Cf/SiC was fabricated by Hot-Press sintering method. It was shown that the bending strength measured by three-point bending test at room temperture, depended on the specimen width of Cf/SiC and span/depth ratio. That is to say, the bending strength of Cf/SiC increased with specimen width, and were obtained maximum at span/depth ratio of 20 and constant values at span/depth ratio of larger than 20. Also, it was shown that fracture behaviour in bending tests depended on span length.View full abstractDownload PDF (1312K) -
Hideto Yoshida, Noboru Miyata, Kazunari Naito, Chitake Yamagishi1994 Volume 41 Issue 7 Pages 821-825
Published: July 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSSiC thin film were continuously coated by CVD method on carbon bundle, which were consisted of thousands filaments. The film was made from high purity SiC and it was high dense. Each filaments of the bundle was coated homogeneously by sub-micron SiC. SiC⋅Cf/SiC composites were fabricated by using these surface modified carbon fibers. Characteristics and mechanical properties of SiC⋅Cf/SiC composite were compared with those of Cf/SiC composite. Mechanical properties of SiC⋅Cf/SiCcomposite differed from those of Cf/SiC composite. It was considered that the difference of them was caused by the decrease of the interfacial strength between fiber and matrix in SiC⋅Cf/SiC composites.View full abstractDownload PDF (3501K) -
Hideto Yoshida, Kazunari Naito, Noboru Miyata, Chitake Yamagishi1994 Volume 41 Issue 7 Pages 826-830
Published: July 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSSiC coated carbon fiber (SiC⋅Cf) and carbon fiber (Cf) were used to fabricate SiC composites reinforced with unidirectionally oriented carbon fibers (Cf/SiC and SiC⋅Cf/SiC). Mechanical properties of SiC⋅Cf/SiC composite differed much from those of Cf/SiC composite. Flexural strengths at room temperature and 1450°C of SiC⋅Cf/SiC composite are smaller than those of Cf/SiC composite. On the othe hand, fracture energy of SiC⋅Cf/SiC composite is larger than that of Cf/SiC composite.
It was considered that the difference of them was caused by changes of the interfacial strength between fiber and matrix in the composite.View full abstractDownload PDF (1620K) -
Osamu Kimura1994 Volume 41 Issue 7 Pages 831-834
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSCeramic composites have been prepared by incorporating ceramic particles or ceramic whiskers into ceramic matrix. Hitherto, thermal expansion coefficients of the inclusions should be lower than those of matrix since it was expected that compressive residual thermal stress resulted in the matrix according to the well-known Selsing's theory. X ray diffraction and neutron diffraction experiments however, revealed existence of uniform tensile stress in matrix in Al2O3/SiC whisker composites or an Al2O3 /SiC particulate composite. This paper tries to explain the discrepancy between the above theory and the experiments, according to the average stress theory developed by Mori and Tanaka in terms of image effects of inclusions proposed by Eshelby.View full abstractDownload PDF (204K) -
Tatsuya Shiogai, Kazuyoshi Minamisawa, Mutsuo Hayashi, Chitake Yamagis ...1994 Volume 41 Issue 7 Pages 835-838
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe microstructure and the creep properties of SiC/β-SiAlON composites were investigated. The grain size of β-SiAlON in SiC/ β-SiAlON composites was smaller than that of β-SiAlON ceramics. And a part of sintering aid existed at inside of β-SiAlON grains in SiC/β-SiAlON composites. SiC/β-SiAlON composites and annealed composite were raised the starting temperature of deformation in creep. It is considered that the rising temperatures result from suppressed slipping in the grain boundary, decrease and crystallization of the grain boundary glass phase.View full abstractDownload PDF (2290K) -
Tatsuya Shiogai, Kazuyoshi Minamisawa, Mutsuo Hayashi, Chitake Yamagis ...1994 Volume 41 Issue 7 Pages 839-842
Published: July 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSThe flexural stress rupture and creep at 1350°C of SiC/β-SiAlON composites were investigated. The rupture in short time was not found on creep test of SiC/β-SiAlON composites in the range of low flexural stress compared with β-SiAlON ceramics. And SiC/β-SiAlON composites in creep were not failed under 250 MPa for more than 1000hr. Yb was concentrated in surface of the composite after creep test. And the layer without Yb was observed under surface layer.View full abstractDownload PDF (1277K) -
Toshihiko Nishida, Tohru Takabayashi, Takaki Masaki1994 Volume 41 Issue 7 Pages 843-847
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSVickers impression was applied on the polished surface of Y-TZP and WC/Y-TZP specimens with an impression load of 50 kgf. After the surface of the specimen was again ground out and polished to remove the indentation follow, it was aged at about 150°C for various times in air. The phase transformation in the locally stressed region beneath the indentation impression was investigated by X-ray analysis, SEM observation and surface profile measurement.View full abstractDownload PDF (4852K) -
Hiroshi Tomimori1994 Volume 41 Issue 7 Pages 851-856
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDiamond tools are applied in a wide variety of precision machining from jet-engine, automobile, electronics parts to medical treatment of teeth and eyes, manufacturing of tomb stones. In finishing the representative powder metallurgy products, cemented carbides and cermets, diamond wheels are indispensable.
The diamond tool market is introduced compared with cemented carbide, high speed steel tools and conventional grinding wheels.
A variety of diamond tools, classified by pressing-sintering process, will be introduced. In addition, it will be mentioned how powder metallurgy is utilized in manufacturing diamond tools.View full abstractDownload PDF (3196K) -
Soft-ferrites and Permanent MagnetsHisae Minatono1994 Volume 41 Issue 7 Pages 857-862
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESS1. The magnetic material markets, especially recent shipments of Soft Ferrites and Permanent Magnets in Japan, are reported.
2. Recent technical topics of Soft Ferrites are discussed.
3. The history of development in Permanent Magnets are reported.
4. At the end we discuss on foresight of new type Magnets (anisotropic Nd-Fe-B bonded magnets and nitricmagnets).View full abstractDownload PDF (342K) -
Fumio Hamano1994 Volume 41 Issue 7 Pages 863-870
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe production in Electronic Materials Industry is under the large influence of the trends in Electronic Industry which is the major field of the demand; Industrial Electronic Appliance which is mainly composed of computer and communication equipments, Consumer Electronic Appliance which is mainly composed of video equipments (Home TV, Video etc.), and Electronic Components & Devices (semiconductors, ICs, display devices). First, the trend of electronic ceramic components is introduced by over-view of Japanese production changes of Electronic Industry and Electronic Materials (the association handling) in past ten years. Second, the demand forecasting of each production which is based on the trend of its related electronic equipment is introduced. Third, the major production groups and the technology trend of electronic equipments & devices which largely influence the technological trend of electronic ceramic components are introduced. Finally, the technology trend of electronic ceramic components is outlined. Only over-view of the field of Industrial Electronic Appliance, the market of Electronic Industry is annually expanding, as operation of Mobile Communication at Sub-microwave band (L band) is starting, Multi-Media era which is information equipment related is coming, and electronics applying in Automobile related equipment is developing. In connection with these, the demand expansion of Electronic Materials and rapid progress of the technology are expected.View full abstractDownload PDF (475K) -
Nobuaki Asada, Tadashi Igarashi, Yoshihiko Doi1994 Volume 41 Issue 7 Pages 871-876
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSEffects of 1 mass% of each of ZrC, VC, MO2C, Cr3C2, and TaC addition on micro structure, high and room temperature Vickers hardness, and transverse rupture strength of submicron WC-8mass%Co hardmetal were investigated.
Results obtained were summarized as follows: Grain growth of mean grain size of WC was inhibited, and the mechanical properties of submicron hardmetals were improved by the addition of each carbide.
This raising of hardness was seemed to be governed by refinement of WC grains by the carbide addition. Vickers hardness of submicron hardmetals with carbide additions, at elevated temperature, are higher than that of these hardmetals without carbide addition. There are two different ranges of temperature dependence on hardness of submicron hardmetals. In this paper, the point of refraction is defined as "softening temperature." The softening temperature was higher in the order of no addition, VC, TaC, ZrC, MO2C, and Cr3C2 addition.
This reason has been estimated to be solid solution strengthening of cobalt binder phase.View full abstractDownload PDF (3003K) -
Kouji Shimayoshi, Keiichi Ishihara, Hideo Shingu1994 Volume 41 Issue 7 Pages 877-880
Published: July 15, 1994
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSAn Electro-Discharge Compaction (EDC) process has been developed to consolidate the intermetallic compound TiAl from the compact of atomized TiAl powders. The EDC process was performed by subjecting high voltage(-15KV). high density electric current from a capacitor bank of 350μF to the compact tinder a pressure of 40MPa. The TiAl compound of 97% density with bending-strength of G2.8kgf/mm2, Vickers micro-hardness of GGOHv, grain size of 32nm was obtained.View full abstractDownload PDF (3003K) -
Tetsuo Kato, Hirotaka Kanazawa, Makoto Kawamura, Tomio Kono, Katsushi ...1994 Volume 41 Issue 7 Pages 881-887
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSEffects of addition of the mixed oxide powder (SiO2, CaO and Al2O3) on the magnetic properties of the low carbon Fe-13Cr-0.8Si sintered alloy were studied. The magnetic characteristics of samples in direct magnetic field degraded with addition of oxide powder, though that indicated to increase with rising the sintering temperature. On the contrary, the amplitude relative permeability of samples in alternating magnetic field was higher in the case of 0.1-0.2% addition of oxide powder than no addition one. Though the relative permeability showed a change of increase and then decrease with rising the sintering temperature, proportion of the decrease in the relative permeability at the higher sintering temperature was restrained by addition of the oxide powder. These phenomena were discussed in the relation of sintered density, porosity and electrical resistivity.View full abstractDownload PDF (457K) -
Kazuharu Iwasaki, Ken Hosoya, Yoshimi Takahashi1994 Volume 41 Issue 7 Pages 888-894
Published: July 15, 1994
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSBonded soft ferrite using injection molding is expected to have applications, because it conforms with the trend toward miniaturization and complication of the shape of electronic devices, At present, the permeability of bonded soft ferrite is too low for it to have practical applications, because of the mixture of ferrite powder and resin. Increasing its permeability is thus an important problem to be solved. To this end, we used kneading and injection molding to produce bonded soft ferrites mixed with nylon resin and several kinds of NiCuZn ferrite powder with various size distributions, and then measured the soft magnetic properties and electric resistance of bonded NiCuZn ferrites.View full abstractDownload PDF (321K)
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