Papers by Author: Kiyoshi Mizuuchi

Paper TitlePage

Authors: Kiyoshi Mizuuchi, Kanryu Inoue, Yasuyuki Agari, M. Sugioka, M. Tanaka, T. Takeuchi, J. Tani, M. Kawahara, Y. Makino, Mikio Ito
Abstract: Diamond-particle-dispersed aluminum (Al) matrix composites consisting of monomodal and bimodal diamond particles were fabricated in spark plasma sintering process, where the mixture of diamond, pure Al and Al-5mass% Si alloy powders were consolidated in liquid and solid co-existent state. Microstructures and thermal properties of the composites fabricated in such a unique way were investigated and the bimodal and monomodal diamond particle effect was evaluated on the thermal properties of the composites. The composites can be well consolidated in a temperature range between 773 K and 878 K and scanning electron microscopy detects no reaction product at the interface between the diamond particle and the Al matrix. Relative packing density of the composite containing monomodal diamond particles decreased from 99.1% to 87.4% with increasing volume fraction of diamond between 50% and 60%, whereas that of the composite containing bimodal diamond particles was higher than 99% in a volume fraction of diamond up to 65%. The thermal conductivity of the composite containing bimodal diamond particles was higher than that of the composite containing monomodal diamond particles in a volume fraction of diamond higher than 60% and the thermal conductivity of the composite containing 70 vol.% bimodal diamond particles was 578 W/mK at R.T..
2462
Authors: Yoritoshi Minamino, Yuichiro Koizumi, Nobuhiro Tsuji, Naoko Hirohata, Kiyoshi Mizuuchi, Yoshihira Ohkanda
Abstract: Three kinds of bulk nanocrystalline Fe-24at%Al-Xat%C (X=1,2,4) alloy were produced from Fe and Al powders with addition of methanol by MA with subsequent SPS at 1273K under 64MPa. Their microstructure and mechanical properties were investigated. The compacts have the relative densities of 99.97% (1at%C) to 99.6% (4at%C). The structure of compacts with 1at%C is composed of Fe3Al grains of 1.5µm in diameter and nano k-carbides (Fe3AlC0.5) precipitates, while those of compacts with 2 and 4at%C are composed of nanocrystalline Fe3Al of about 80nm in diameter, nano k-carbides and a-grains of about 1µm in diameter. These structures have the good thermal stability, maintaining the nanostructure even at 973K. The mechanical properties of these compacts were measured by compression tests at R.T. to 973K. The compacts with 1at%C and 2at%C of this work perform the superior mechanical properties (e.g. yield strength of 2.15GPa and rupture strain of 0.14 for compact with 2at%C at R.T.) when compared with the ordinary Fe3Al casting (e.g. 380MPa and 0.12). They also exhibit no environmental embrittlement, which is one of fatal problems for the ordinary Fe3Al mateials.
103
Authors: Kiyoshi Mizuuchi, Masami Sugioka, Masao Itami, Masakazu Kawahara, J.H. Lee, Kanryu Inoue
1757
Authors: Kiyoshi Mizuuchi, Takashi Takeuchi, Kanryu Inoue, Jun Hee Lee, Masami Sugioka, Masao Itami, Masakazu Kawahara, Isamu Yamauchi, Hiroshi Asanuma
Abstract: Boron-fiber-reinforced Al-matrix composite was fabricated by a pulsed current hot pressing (PCHP) process at a pressure of 32MPa for 600s. It was found that the boron fiber and the Al-matrix were well bonded when the PCHP process was performed at a holding temperature of 773K. No interfacial reaction layer was observed along the interface between the boron fiber and the matrix when PCHP was done at 773K for 600s. Tensile deformation carried out at room temperature for the composite showed that the tensile yield stress increased with increasing volume fraction of the boron fiber in the composite. The composite with 17.2 vol.% of boron fiber presented a tensile yield stress of 600MPa. This value was about 90% the yield stress estimated by a force equilibrium equation of a composite taking into account the direction of fiber axis.
3139
Authors: Hirota Ken, Takaya Endo, Kato Masaki, Shingo Nakane, Toshiyuki Nishimura, Yoshiaki Morisada, Kiyoshi Mizuuchi
Abstract: Dense zirconium boride (ZrB2)-based materials with and without tungsten (W) have been fabricated directly from mixtures of constituent elemental powders by pulsed electric current pressure sintering (PECPS) at 1800°C for 10 min under 30 MPa in a vacuum. Formation processes of monolithic, W-doped ZrB2 solid solutions (Zr1-xWx)B2 (0
527
Authors: Yukio Makino, Kiyoshi Mizuuchi, Masao Tokita, Yasuyuki Agari, Masakazu Kawahara, Kanryu Inoue
Abstract: Capabilities of synthesizing new structural and functional materials by SPS processing were indicated by exemplifying the synthesis of nano-structured alumina with high bending strength or high transparency, Al/diamond composites with high thermal conductivity and zirconia(3Y)/ SUS410L FGM. In the synthesis of alumina, the bending strength of more than 720MPa was attained by choosing suitable SPS conditions. It was also indicated that SPS processing could easily synthesize Al/diamond composites with high thermal conductivity of more than 400W/(m・K), suggesting elaborate control of interface between Al and diamond in SPS consolidation. Further, zirconia(3Y)/SUS410L FGM could easily be fabricated by SPS. Mechanical weakness in the zirconia(3Y)-rich layers of the FGM was shown from the analysis of stress state based on Raman scattering method. It is suggested that the designing of the layer staking in FGM based on the Raman scattering analysis is effective for the improvement of the weakness in the FGM.
2091
Authors: Kiyoshi Mizuuchi, Kanryu Inoue, Yasuyuki Agari, Motohiro Tanaka, Takashi Takeuchi, Jun Ichi Tani, Masakazu Kawahara, Yukio Makino, Mikio Ito
Abstract: Cubic boron nitride (cBN) particle-dispersed-aluminum (Al) matrix composites were fabricated from the powder mixture composed of cBN, pure Al and Al-5mass% Si alloy in liquid and solid co-existent state by spark plasma sintering (SPS) process. Al/cBN composites were well consolidated by heating at a temperature range between 798 K and 876 K for 1.56 ks by SPS. Microstructures of the composites produced were examined by scanning electron microscopy and the reaction between the cBN particle and the Al matrix was not detected. The relative packing density of the Al/cBN composite was higher than 99 % in a volume fraction range of cBN up to 45 %. The thermal conductivity of the composite increased with increasing the cBN content in the composite in a volume fraction range of cBN between 35 and 45 vol. %. The highest thermal conductivity of 305 W/mK was obtained for Al matrix composite containing 45 vol.% cBN particles.
2413
Authors: Kiyoshi Mizuuchi, Kanryu Inoue, Yasuyuki Agari, Yoshiaki Morisada, Masami Sugioka, Motohiro Tanaka, Takashi Takeuchi, Junichi Tani, Masakazu Kawahara, Y. Makino, Mikio Ito
Abstract: Diamond-particle-dispersed-aluminum (Al) matrix composites were fabricated in continuous solid-liquid co-existent state by spark plasma sintering (SPS) process from the mixture of diamond powders, pure Al powders and Al-5mass%Si alloy powders. The microstructures and thermal conductivities of the composites fabricated were examined. These composites were well consolidated by heating at a temperature range between 798K and 876K for 1.56ks during SPS process. No reaction at the interface between the diamond particle and the Al matrix was observed by scanning electron microscopy for the composites fabricated under the sintering conditions employed in the present study. The relative packing density of the diamond-Al composite fabricated was 99% or higher in a volume fraction range of diamond between 45% and 50%. Thermal conductivity of the diamond-Al composite containing 50 vol.% diamond reached 552W/mK, approximately 95% the theoretical thermal conductivity estimated using Maxwell-Eucken’s equation.
1967
Authors: Kiyoshi Mizuuchi, Kanryu Inoue, Yasuyuki Agari, Shinji Yamada, Motohiro Tanaka, Masami Sugioka, Takashi Takeuchi, Junichi Tani, Masakazu Kawahara, Jun Hee Lee, Yukio Makino
Abstract: Diamond-particle-dispersed copper (Cu) matrix composites were fabricated from Cu-coated diamond particles by spark plasma sintering (SPS) process, and the microstructure and thermal properties of the composites fabricated were examined. These composites can well be consolidated in a temperature range between 973K and 1173K and scanning electron microscopy detects no reaction at the interface between the diamond particle and the Cu matrix. The relative packing density of the diamond-Cu composite increases with increasing sintering temperature and holding time, reaching 99.2% when sintered at a temperature of 1173K for a holding time of 2.1ks. Thermal conductivity of the diamond-Cu composite containing 43.2 vol. % diamond increases with increasing relative packing density, reaching a maximum (654W/mK) at a relative packing density of 99.2%. This thermal conductivity is 83% the theoretical value estimated by Maxwell-Eucken equation. The coefficient of thermal expansion of the composites falls in the upper line of Kerner’s model, indicating strong bonding between the diamond particle and the Cu matrix in the composite.
2115
Showing 1 to 9 of 9 Paper Titles