巻号一覧
62 巻, 5 号
May
選択された号の論文の9件中1～9を表示しています
- |<
- <
- 1
- >
- >|
特集：電磁プロセスを含む新しい粉末成形技術による新機能発現
総報
-
水内 潔2015 年 62 巻 5 号 p. 220-
発行日: 2015/05/15
公開日: 2015/06/04
ジャーナル オープンアクセスPDF形式でダウンロード (207K)
研究論文
-
井藤 幹夫, 川原 賢太2015 年 62 巻 5 号 p. 221-227
発行日: 2015/05/15
公開日: 2015/06/04
ジャーナル オープンアクセスSynthesis of the thermoelectric Mg2Si sintered body was tried by reactive pulsed current sintering (PCS) using graphite punches and a nonconductive quartz glass die (directly applied current sintering). The mechanically milled powder mixture of Mg and Si was heated by directly applied current sintering, and the densification behaviour, Mg2Si phase formation and the power consumption during sintering, the relative density and the microstructure of the sample were compared to those of a sample sintered by the conventional PCS (using graphite punches and a graphite die). When the mechanically milled powders were heated by directly applied current sintering, the densification of a powder compact became larger during heating and the density of a sintered body was also significantly higher as compared to those of the sample sintered by the conventional PCS. The relative density of a compound sintered in a quartz die at 973 K for 10 min was 99.3 %, which is almost the same as that of the sample sintered by the conventional PCS at 1073 K for 60 min, 99.6 %. Furthermore, directly applied current sintering is found to accelerate the reaction between Mg and Si to form Mg2Si phase.抄録全体を表示PDF形式でダウンロード (1253K) -
Masakazu KAWAHARA, Tohru SHIROSAWA, Takuya YASUNO, Mikio ITO, Yukio MA ...2015 年 62 巻 5 号 p. 228-233
発行日: 2015/05/15
公開日: 2015/06/04
ジャーナル オープンアクセスMicrostructure and control of pore formation in SPS-synthesized alumina were investigated by TEM and SEM observation. In addition, the relationship between the morphology of pores in the alumina and the bending strength of the alumina was examined. SPS consolidation at a high heating rate of 200 °C/min and at a high pressure of 100 MPa is effective for the fabrication of nano-structured and highly-transparent alumina without residual pores.
It has been indicated that the interrelation between plastic deformation, neck formation, heating rate, densification and grain growth is important for the synthesis of nano-structured ceramics without residual pores.抄録全体を表示PDF形式でダウンロード (643K) -
神田 康行, 福本 功2015 年 62 巻 5 号 p. 234-242
発行日: 2015/05/15
公開日: 2015/06/04
ジャーナル オープンアクセスBagasse is a by-product obtained from squeezed sugar cane. In this study, composite materials were fabricated from powder mixtures of carbonized bagasse and Ti, using spark plasma sintering (SPS). This achieves effective use of bagasse and mechanical strength improvement of carbon ceramics. TiC was synthesized by a chemical reaction between the carbon in carbonized bagasse and Ti powder during SPS. The flexural strength of the composite material fabricated by SPS was maximum at a Ti content of 1 vol.%, and decreased with increasing Ti content above 1 vol.%. The flexural strength of the composite material containing 3 vol.% Ti powder was significantly lower than that of the composite containing 1 vol.% Ti powder. Next, the mechanical properties of the composite materials were investigated using the finite element method (FEM) to examine crack propagation. FEM result suggests that crack coalescence in the composite material occurs during flexural deformation, because of the decrease in the distance between TiC particles as a result of the increased Ti content of the composite material.抄録全体を表示PDF形式でダウンロード (2162K) -
神田 康行, 山里 將史, 福本 功2015 年 62 巻 5 号 p. 243-251
発行日: 2015/05/15
公開日: 2015/06/04
ジャーナル オープンアクセスFrom the point of view that fly ash has very fine particles which included silica and alumina component of ceramic material, composite materials using fly ash and aluminum powders were fabricated by spark plasma sintering technique. The bending strength showed the constant value of 530 MPa at the fly ash content lower than 9.1 %, however the strength decreased monotonically at the fly ash content higher than 9.1 %. In addition, the bending fracture strain decreased with increasing the fly ash content. From the fracture surface observation, the crack propagation was recognized as bypassing along interface of fly ash particle. This phenomenon indicated that the fly ash particles played a role for suppressing the crack propagation. By assuming fly ash particle as spherical shape, the Mises stress distributions were analyzed by finite element method. The high stress concentrated near interfaces of fly ash particles, because deformation degree of aluminum alloy matrix and fly ash were different. This result suggested that the cracks occurred around fly ash particle combined each other, because the agglomerated fly ash particles becomes large size when increasing the fly ash content. And the simulation results showed the agreement with experimental results of fracture strain on the bending test.抄録全体を表示PDF形式でダウンロード (2462K) -
長岡 亨, 木元 慶久, 渡辺 博行, 福角 真男, 森貞 好昭, 藤井 英俊2015 年 62 巻 5 号 p. 252-257
発行日: 2015/05/15
公開日: 2015/06/04
ジャーナル オープンアクセスFriction stir processing of a thermally sprayed WC-CrC-Ni cemented carbide layer was carried out to clarify the optimum conditions for obtaining a hardened layer without any cracks and pores. Although cracks and pores were observed in the cemented carbide layer after friction stir processing at a forging load of 4.9 kN, friction stir processing at a higher forging load of 9.8 kN or 14.7 kN could eliminate these defects. The amount of pores was decreased owing to rearrangement of WC particles by the stirring effect. The cracks were suppressed by densification of the cemented carbide layer and the martensitic transformation of the SKD61 substrate during cooling. When the forging load was 14.7 kN, the hardness of the cemented carbide layer reached to 2200 HV. On the other hand, friction stir processing at 19.6 kN caused large plastic deformation of the SKD61 substrate and cracks occurred in the cemented carbide layer on the advancing side.抄録全体を表示PDF形式でダウンロード (1991K) -
木元 慶久, 長岡 亨, 渡辺 博行, 福角 真男, 森貞 好昭, 藤井 英俊2015 年 62 巻 5 号 p. 258-262
発行日: 2015/05/15
公開日: 2015/06/04
ジャーナル オープンアクセスFriction stir powder processing (FSPP) can produce metal matrix composites (MMCs) in the stir zone. Unlike the conventional technologies such as powder metallurgy or molten metal processing, it is still challenging for FSPP to produce high-particle-content MMCs, and the mechanical and functional properties are limited. In this study, a simple repeatable procedure, named accumulative FSPP (AFSPP), is employed to increase the particle content in FSPP composites. The process has successfully accumulated the SiC particles into the pure Al matrix, and the microhardness has constantly increased by the repetition of the AFSPP. The maximum microhardness for the 4-time AFSPP sample has been 133 HV, 5.3 times of the base metal. The volume fraction has achieved 58 % near the maximum hardness point.抄録全体を表示PDF形式でダウンロード (1248K)
研究速報
-
水内 潔, 井上 漢龍, 上利 泰幸, 杉岡 正美 , 田中 基博, 武内 孝, 谷 淳一, 川原 正和, 巻野 勇喜雄, 井藤 幹夫2015 年 62 巻 5 号 p. 263-270
発行日: 2015/05/15
公開日: 2015/06/04
ジャーナル オープンアクセスCubic boron nitride (cBN)-particle-dispersed-aluminum (Al) matrix composites were fabricated in solid-liquid co-existent state by Spark plasma sintering (SPS) process from the mixture of cBN powders, Al powders and Al-5 mass%Si powders. As the cBN powders, two kind of powders, monomodal cBN powders of 390 μm in diameter and a bimodal cBN powder mixture of 390 μm and 39 μm in diameter, were used. The microstructures and thermal conductivities of the composites fabricated were examined. These composites were all well consolidated by heating at a temperature range between 798 K and 876 K for 1.56 ks during SPS process. No reaction at the interface between the cBN particle and the Al matrix was observed by scanning electron microscopy for the composites fabricated under the sintering conditions employed in the present study. Although the relative packing density of the monomodal composite decreased from 99.5 % to 89.5 % with increasing the cBN volume fraction in a diamond volume fraction range between 50 % and 60 %, that of the bimodal composite was higher than 98.6 % in a cBN volume fraction range up to 65 %. The thermal conductivity of the bimodal composite was 306–325 W/mK, which is higher than that of the monomodal composite in a diamond volume fraction range higher than 45 %. The coefficients of thermal expansion of the composites were a little higher than the theoretical values estimated by the upper line of Kerner’s model, indicating the bonding between the cBN particle and the Al matrix in the composite is weak a little.抄録全体を表示PDF形式でダウンロード (1681K)
本会記事
-
2015 年 62 巻 5 号 p. Pref5_1-
発行日: 2015/05/15
公開日: 2015/06/04
ジャーナル オープンアクセスPDF形式でダウンロード (184K)
- |<
- <
- 1
- >
- >|