All issues
Volume 48, Issue 5
Displaying 1-13 of 13 articles from this issue
- |<
- <
- 1
- >
- >|
-
Tadahiro Wada, Masatoshi Sakurai, Akihiko Ogura2001 Volume 48 Issue 5 Pages 386-391
Published: May 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe tool life in turning of the sintered materials such as sintered steel becomes shorter than that in turning of the melted steels such as carbon steel. In order to clarify the effective tool materials for the turning, the tool wear etc. in the turning of the sintered iron material was experimentally investigated. The sintered iron material was turned with the various tool materials at the cutting speed 5.0m/s. The main results obtained are as follows: (1) In the PVD/CVD coated cemented carbide tools, the wear progress of the TiVN PVD coated cemented carbide tool was slowest. (2) In the four kinds of ceramics tools, the wear progress of the Si3N4 ceramics tool was slowest. And, the wear progress of the Si3N4 ceramics tool became slower than that of the TiVN PVD coated cemented carbide tool. (3) The main wear mechanisms of the ceramics tools were the abrasive wear.View full abstractDownload PDF (6724K) -
Ryosuke Ueyama, Tamotsu Ueyama, Kunihito Koumoto, Takashi Yamamoto, Ki ...2001 Volume 48 Issue 5 Pages 392-396
Published: May 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSThe dispensability of BaTiO3 powder in Ni paste for multilayer ceramic capacitors and the effect of amount of added BaTiO3 on the properties of Ni Electrode were studied. Maximum green density of Ni paste film dried at 100°C was obtained when the amount of added BaTiO3 was 15 mass%.
With addition of BaTiO3 powder, the shrinkage of Ni electrode decrease and the electrical resistivity of Ni electrode increased. The amount of added BaTiO3 powder should be less than 30 mass%, because the electrical resistivity increased abruptly when amount of the powder was over 30 mass%.View full abstractDownload PDF (1965K) -
Akihiro Yamazaki, Junichi Kaneko, Makoto Sugamata2001 Volume 48 Issue 5 Pages 397-403
Published: May 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSPure magnesium powders were mechanically alloyed with addition powders of low-melting-metal oxides (SnO2, PbO and Sb2O3) by using a planetary ball mill under an Ar atmosphere. After mechanical alloying, the powders were consolidated to the P/M materials by vacuum hot pressing. Solid state reaction in the mechanically alloyed powders and the P/M materials was studied by XRD and DSC. In these systems, the solid state reaction started to occur during MA processing between Mg and low-melting-metal oxides. The added low-melting metal oxides decomposed and formation of MgO and intermetallic compounds (Mg2Sn, Mg2Pb, Mg3Sb2) occurred. Such solid state reaction further progressed during hot-pressing and subsequent heat treatment. Microstructures were studied by TEM and mechanical strength was discussed by hardness values for both MA powders and P/M materials.View full abstractDownload PDF (1647K) -
Akihiro Yamazaki, Junichi Kaneko, Makoto Sugamata2001 Volume 48 Issue 5 Pages 404-411
Published: May 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSPure magnesium powders were mechanically alloyed with addition of metal silicide powders (TiSi2, CrSi2 and WSi2) by using a planetary ball mill under an Ar atmosphere. After mechanical alloying, the powders were consolidated to the P/M material by vacuum hot pressing. Solid state reaction in the mechanically alloyed powders and the P/M material was studied by XRD and TEM. In these systems, the solid state reaction occurred during mechanical alloying and subsequent heat treatment. The added metal silicides were decomposed and Mg2Si dispersoids were formed in the Mg matrix which was alloyed with elements (Ti, Cr or W).View full abstractDownload PDF (5146K) -
[in Japanese]2001 Volume 48 Issue 5 Pages 414
Published: May 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDownload PDF (81K) -
Masato Imamura2001 Volume 48 Issue 5 Pages 415-421
Published: May 15, 2001
Released on J-STAGE: July 12, 2010
JOURNAL OPEN ACCESSThe rapid prototyping technology was born with the development of laser stereolithography. At the beginning, metal products were made by replication using laser stereolithography models as the master. Since then, numerous developments on the use of various materials for the layer lamination method, the basis of the RP method, have been attempted. This paper discusses the trends of fundamental developments and the methods of using metal powder in RP.View full abstractDownload PDF (5342K) -
Masashi Arita2001 Volume 48 Issue 5 Pages 422-425
Published: May 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSGeneral remarks of the recent trend of fuel cell vehicles were presented. Polymer Electrolyte Fuel Cell (PEFC) has been thought to be suitable for fuel cell vehicles because it operates at low temperature and developed by many manufacturers. The power density of recent PEFCs is reaching to the level in which fuel cells can be installed under the floor but some issues are remained. Solid Oxide Fuel Cell (SOFC) is suitable for gasoline-reformed Fuel Cell Vehicle (FCV) but it is necessary to lower the operating temperature to use for vehicles. The main candidates of fuels for FCVs are hydrogen, methanol and gasoline. Hydrogen is the cleanest fuel and many manufacturers think that it will be the best fuel in the future. Methanol is thought to be used only for research. Gasoline has an advantage of its infrastructure and it will be appropriate in the short or middle term.View full abstractDownload PDF (4535K) -
Tetsuya Hayashi, Kentaro Azetsu2001 Volume 48 Issue 5 Pages 426-431
Published: May 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSCylinder liner for motorcycle engines made of aluminum powder metallurgy composites, P.M.C., have been developed with powder-extrusion techniques through a joint project with HONDA R&D Co., Ltd. This P.M.C. is consisted of rapidly solidified powder comprised of Al-17Si-5Fe-3.5Cu-1Mg-0.5Mn with fine spherical alumina particles and fine graphite powder additives, which has excellent wear resistance equivalent to the gray cast iron in used with both piston and piston ring. It is considered that the uniformly dispersed fine alumina particles and graphite powders in the matrix improve the tribological properties, Furthermore, the hardness was not decreased by the thermal history during the die casting process compared with the conventional casting aluminum alloy such as A390. This alloy also has good machinability, that is, the tool wear is almost equivalent to the conventional gray cast iron. This P.M.C. has been applied to the cylinder liner for automotive engines.View full abstractDownload PDF (5996K) -
Takayuki Hirao, Yuji Kishi, Takeshi Katagiri2001 Volume 48 Issue 5 Pages 432-439
Published: May 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn standard P/M (Press-Sinter) technique, it is difficult to make under-cut shape parts. In this development, the possibility of under-cut forming by a CNC press was investigated in the basic experiment. And an under-cut shape sprocket of whole circumference was made by the CNC press and the newly designed die and tools. This paper describes the features of the CNC press and technical issues encountered in the production of the sprocket of the under-cut shape. These are as follows: 1) Elimination of cracks and burrs in compaction, 2) Achievement of an even density throughout the complex part, 3) Keeping the dimensional tolerance and 4) Prevention of breakage of the die and tools. These were resolved by using newly designed die and tools. These are described in detail.View full abstractDownload PDF (4170K) -
Akira Fujiki, Hisayoshi Kojima, Yukihiro Maekawa, Masato Yamaguchi, Ta ...2001 Volume 48 Issue 5 Pages 440-444
Published: May 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSSince the introduction of warm compaction in 1994, several new warm-compacted powder metallurgy (P/M) parts have been developed. However, the main applications to date have been limited to machine tool parts and parts for agricultural tools, for example. Only a few automotive parts have been developed by using the warm-compaction method. Engine parts have not yet to be developed, particullary. Here, we investigate the mechanical properties and wear resistance of warm-compacted P/M materials, and the developed warm-compacted P/M engine sprockets. A method of controlling the powder temperature is also described.View full abstractDownload PDF (1960K) -
Susumu Takizawa, Ryuzo Watanabe, Akira Kawasaki2001 Volume 48 Issue 5 Pages 445-450
Published: May 15, 2001
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSIn-situ measurement of non-uniform sintering shrinkage of guide-type (ring-on-plate) MIM compacts was made by digital image correlation method. The shrinkage distribution and the distortion in the compacts were determined with a dimensional accuracy of 3μm. A periodical shrinkage distribution in the ring portion was observed in the compact during sintering, due to density distribution generated presumably by an uneven injection flow from gates located at the both ends of the base plate. An upward warpage of the base plate and a collapse of the ring portion were also observed. The inhomogeneous radial shrinkage, the base-plate warpage and the ring-collapse were interpreted in terms of the ring-portion density distribution and the effect of gravity. The periodical variation in the radius distribution during sintering was attributed to the green density distribution. A simple geometrical consideration showed that the distortion due to gravity was estimated to be approximately 2% at the most.View full abstractDownload PDF (1988K) -
Mitsuhiro Matsuda, Hideshi Miura2001 Volume 48 Issue 5 Pages 451-455
Published: May 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn the previous report on the sintered low alloy steels (4600grade, 0.4mass%C) produced by MIM process varying Ni content from 0 to 8 mass%, the mechanical properties were improved significantly with increasing Ni content to 6mass%. This was attributed to the solution strengthening and the mezzo-heterogeneous microstructure which were consisted of Ni rich martensite surrounded by a network of tempered martensite. However, the tensile and fatigue strength of the steel added 8 mass% Ni were dropped by the increase of retained austenite. In this study, the effect of the different type of Ni powders on the mechanical properties of Fe-6Ni-0.5Mo-0.2Mn (mass%) was investigated to clarify and optimize the mezzo-heterogeneous microstructure.
The tensile properties of the heat treated steels using the spherical Ni powder were lower than those using the spiky Ni powder. This seems to be due to the segregated distribution considerably of Ni rich phase and the decrease of Ni diffusion rate.View full abstractDownload PDF (3572K) -
Hideshi Miura, Akira Taniguchi, Mitsuhiro Matsuda2001 Volume 48 Issue 5 Pages 456-460
Published: May 15, 2001
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSIn our previous studies on the 4600 steels produced by conventional powder metallurgy (P/M) process using mixed elemental powders, the fine heterogeneous microstructure caused by the agglomeration of Ni powders was reported to be significantly effective for the improvement of mechanical properties. This study has been performed to obtain the high densified compacts using the double press and sintering, and the bimodal powders, and moreover to investigate the relationship between the mechanical properties and the heterogeneous microstructure of the compacts (4600grade, 0.4 mass%C).
The tensile strength of the steels with bimodal powders (coarse : fine = 8 : 2) was improved the most significantly with increasing Ni content to 6 mass%, without loss of the ductility. This seemed to be due to the solution strengthening and the mezzo-heterogeneous microstructure which were consisted of Ni rich martensite surrounded by a network of tempered martensite. However, the tensile strength of the steels with bimodal powders (coarse : fine = 9 : 1) added 6 mass% Ni were dropped by the increase of retained austenite.View full abstractDownload PDF (2340K)
- |<
- <
- 1
- >
- >|