All issues
Volume 50, Issue 3
Displaying 1-15 of 15 articles from this issue
- |<
- <
- 1
- >
- >|
-
Rolling Texture of TiNi Shape Memory Intermetallic Compound Produced by Combustion Synthesis ProcessYoshinari Kaieda2003 Volume 50 Issue 3 Pages 163-167
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe TiNi shape memory intermetallic compound is manufactured by using the combustion synthesis process that author researched and developed. A flat wire is manufactured with many hot and cold plastic workings. The rolling texture is primarily examined to understand the properties of this material influenced by the plastic working. The manufactured TiNi shape memory intermetallic compound has no gravity segregation, and is homogeneous. Because the sample is the TiNi shape memory intermetallic compound of excessive Ni content, it is of Austenitic phase and has B2 structure (CsCl type, bcc) in which super-elasticity is shown at room temperature. Two kinds of rolling textures exist together. The (110) plane appears on the rolling surface in one kind of texture. In this case, RD=(110), TD=(100), and the rolling direction= <110>. The (211) plane appears on the rolling surface in the other texture. In this case, RD=(110), TD =(111), and the rolling direction =<110>. In both of the textures rolling directions are <110>, and the rolling direction planes are (110). These two kinds of crystals have the relationship of rotation to the direction of TD by 54.7- with the RD axis.View full abstractDownload PDF (418K) -
Yasushi Enokido, Taku Murase, Takeshi Nomura, Mamoru Senna2003 Volume 50 Issue 3 Pages 168-171
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe effects of physical properties of MnZn-ferrite slurry on the quality of granules and compacts were discussed. Emphasis is laid on the order of addition of a dispersant and poly vinyl alcohol (PVA) to the starting ferrite slurry. The composite slurries were prepared either by simultaneous addition of dispersant and PVA (Slurry S), sequential addition of PVA followed by dispersant (Slurry D) or dispersant followed by PVA (Slurry P). The viscous flow behavior of all the composite slurries was analyzed on the basis of the Harschel-Bulkley model. Slurry P showed the highest yield point and plastic viscosity. The density of the granules produced from Slurry P was the lowest and its compacts showed the lowest bending strength and the smallest Weibull modulus. These phenomena were interpreted in terms of the irreversible absorption and interaction of dispersant and PVA.View full abstractDownload PDF (363K) -
Eiichi Sentoku, Keigo Yamada, Tatuo Nakagawa, Makoto Nishi2003 Volume 50 Issue 3 Pages 172-176
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIt is possible that the machinable ceramics used in this experiment are subjected to external form cutting, drilling, and tapping by sintered carbide available on the market. The main materials of these ceramics are pottery stone. It was manufactured by a crystallization method. It was composed of borosilicate glass with uniformly distributed fluorphlogophites. The purpose of this study is to clarify the tool form to prevent cracks from remaining on machined surfaces extremely. The three-dimensional cutting experiment and the orthogonal cutting one by produced orthogonal cutting apparatus were carried out. And the relationship between surface roughness and rake angle was investigated by the three-dimensional cutting experiment. The cutting forces necessary for stress analysis were obtained from the experiments. The stress distribution acting on the front of tool edges was calculated by FEM. The relation between the progress of the crack generation and the stress distribution by stress analyses basing on plain strain problems was discussed. As a result, the surface roughness obtained the minimum at rake angle-15°--5°. In conclusion, it was shown that the tool form to obtain machined surfaces of good surface roughness was shown by cutting at a rake angles of -15°.View full abstractDownload PDF (3409K) -
Toru Shimizu, Kunio Matsuzaki2003 Volume 50 Issue 3 Pages 177-181
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSFoam metals are interested as new materials and many researches are continued. Major method for making foam metal is to add the foaming agent into molten metal before casting. However, source metals are limited only to low-melting-point metals. To make foam metal that has high melting point, new methods must be developed. Therefore, methods using metal powder and water based binder are investigated. In one of these methods, slurry is prepared by mixing the metal powder and the water based binder, and foaming agent is added into this. After that, the slurry is heated, and dried. During this process, the slurry foamed into high porosity green body is obtained. In another method, the slurry and paraffin wax are mixed with detergent agent, and frozen. After the paraffin wax is removed and porous green body is obtained. In these processes, the green bodies are sintered and foam metals are obtained. These methods can be applied to most kinds of powder metals and we applied them to make foam stainless steel. Using these methods, foam stainless steel that has more than 80% porosity can be obtained.View full abstractDownload PDF (5561K) -
Yohichi Yamashita, Kiyohide Yoshida, Noriyoshi Kakuta2003 Volume 50 Issue 3 Pages 182-185
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSBaTi4O9 was synthesized at 800°C in its pure form by the polymerizable complex method, which produced a fine powder with a specific surface area of 8.5 m2/g. The photocatalytic activity for NO conversion of BaTi4O9 as well as that of BaTi4O9 impregnated with Ag (i.e. Ag/BaTi4O9) was measured under illumination of ultraviolet (UV) light, and it was compared with the previous results reported for A12O3 and Ag/A12O3 photocatalysts. The BaTi4O9-based photocatalysts showed much superior photocatalytic properties with respect to the conversion of NO.View full abstractDownload PDF (276K) -
[in Japanese]2003 Volume 50 Issue 3 Pages 188
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (70K) -
Minoru Umemoto, Koichi Tsuchiya, Zhi-Guang Liu2003 Volume 50 Issue 3 Pages 189-197
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe mechanism of nanocrystallization in steels by ball milling was studied. The importance of severe plastic deformation at high strain rate rather than repeated cold-welding was recognized. This idea was confirmed by the nanocrystallization in other deformation methods such as a ball drop, a particle impact and shot peening deformations those can apply similar severe plastic deformation to specimens with that of ball milling. The nanocrystalline structure produced by these methods has essentially the same characteristics; sharp boundary with work-hardened region, dissolution of cementite, substantial high hardness (about 10 GPa) and without recrystallization and slow grain growth by annealing. It was proposed that a large strain (larger than 7.3 in true strain) and high strain rate (above about 104/s) are necessary deformation conditions to produce nanocrystalline structure in steels. It was suggested that shot peening is the most practical technique to produce nanocrystalline surface layer.View full abstractDownload PDF (11570K) -
Eiji Yuasa, Tsutomu Yuuki, Ayako Ohguchi2003 Volume 50 Issue 3 Pages 198-204
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSPowder mixture of Al-40mol% Ni was mechanically alloyed for various milling times. After 72 ks of milling, AINi (β') phase has formed. The crystalline size of AM (β') phase decreases with milling time, and it becomes about 30 nm after 180 ks of milling. When the mechanically alloyed Al-Ni alloy powder was heat-treated at 823 K, the AlNi (β') phase transforms to equilibrium AlNi phase with about 40 nm in crystalline size. The 180 ks milled powders was consolidated by the hot pressing (HP) under various conditions, and structural change of the compacts during the HP was investigated. The microstructure of the compacts consists of equilibrium AlNi phase with about 40 nm of crystalline size. Density of the compacts is increased with the increasing of hot pressing pressure and holding time. Compression tests of the compacts have been carried out to investigate mechanical properties at high temperatures. The intermetallic AINi sample made from the MA powder deforms to high strain under low stress, when compressed at 1073K-1123K for 10-1s-1 of initial strain rate. The strain rate sensitivity exponent of yield stress (m-value) reaches to 0.32-0.36 under this compressing condition. Therefore, the ultra fine grained intermetallic AlNi alloy made by the MA and HP process can be formed to near net shapes by superplastic deformation at high strain rate suitable for industrial working.View full abstractDownload PDF (3251K) -
Keizo Kobayashi, Akihiro Matsumoto, Kimihiro Ozaki, Toshiyuki Nishio2003 Volume 50 Issue 3 Pages 205-209
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSTi-2at%Fe-lOat%Si alloy powder was synthesized by a mechanical alloying (MA) using a planetary ball milling as start materials of Ti powder, Fe powder and Si powder. The powders obtained by milling for more than 1440 ks were amorphous state. The recovery percentage of mechanically alloyed powder increased with the milling time. However, the composition and the crystallization temperature of the MA powder were almost unchanged even by varying the milling time. In the case of mechanical alloying for Ti-2at%Fe-1Oat%Si, amorphous powder is produced gradually after adhesion of the MA powder to the MA vessel and MA balls.
The coarse particles of about 2 mm diameter were prepared by the adhesion of amorphous powders during the MA. These coarse particles were formed by filling up the gap between the MA balls of 10mm diameter with amorphous powders. The formation of coarse particles during the MA was able to be prevented by coexistence of the ball with a different size.View full abstractDownload PDF (3579K) -
[in Japanese]2003 Volume 50 Issue 3 Pages 212
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (114K) -
Takayasu Ikegami2003 Volume 50 Issue 3 Pages 213-219
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe Wulff construction suggests that ceramic particles are polyhedral. Simulation experiments were carried out with plastic polyhedra (cuboctahedra, in particular). The packing structures of them were characterized in term of three different types of contacts-point, line, and face contacts. The measured percentage of them ranged from 17% to 23% for point contacts, 60% to 65% for line contacts and 15% to 20% for face contacts. A line contact model well described initial sintering of a commercially available alumina powder consisting of single crystalline particles. Microstructural development, current progresses of densification, grain growth and pore migration in the intermediate-stage are described with five simultaneous equations having four variables, which systematize reported theories on these phenomena.View full abstractDownload PDF (1917K) -
Susumu Natsuyama, Takuya Nagato, Yoshiyuki Kanou, Keijiro Terashita2003 Volume 50 Issue 3 Pages 220-226
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDevices which have the structure of the polygon rotation drum are widely used in the manufacturing industries, e.g., for ball mill, for the mixing device, and for pharmaceutical tablet coating. One of the most important factors in design of these devices is particle mixture characteristic. The mixture characteristic affect on uniformity and efficiency of milling, and uniformity of particle or tablet coating in pharmaceutical industries.
Some baffles are installed in the rotation drum. The installation method of baffles influence on particle mixture characteristic. Therefore, we tried some kind of installation method of baffles, and estimated particle mixture characteristic at the surface of the particle bed in experiment.
In this paper, we applied DEM simulation on estimating particle mixture characteristic in the polygon rotation drum, especially focusing attention on each particle motion.View full abstractDownload PDF (8457K) -
Susumu Natsuyama, Takuya Nagato, Keijiro Terashita2003 Volume 50 Issue 3 Pages 227-232
Published: March 15, 2003
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSRotor fluidized beds are used widely for granulation and particle-suraface coating in various industries. Comparing with conventional fluidized beds, they can produce more spherical granules with high density by the action of the rotor. The air flow pattern in the device changes largely due to the interaction of the inlet air and the rotating rotor, which differs from the conventional fluidized bed granulators. By the various conditions of particle fluidization, we can produce various granule properties. This kind of device widens the range of control of the granule's physical properties. On the other hand, the number of parameters to be considered increases. Observation of the movement of powder and the air flow pattern in the device is difficult or requires complex machines. Logical and analytical reports on the correlation among granule's physical properties are very few. So, we applied DEM simulation method to estimate the particle's flow characteristic in this device numerically. The particle's flow in the device was analyzed under several rotor rotating speeds values as an operation parameter. We studied the relationship between the physical properties of the particles actually produced by the rotor fluidized bed device, especially granule's bulk density and the simulated particle's flow.View full abstractDownload PDF (5613K) -
Kunio Okimoto, Tomotaka Kuroda2003 Volume 50 Issue 3 Pages 233-237
Published: March 15, 2003
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSGenerally the anisotropic permanent magnet is produced by the magnetic field orientation forming, namely, the compaction of magnetic powders under magnetic field. In the magnetic field orientation forming, there is the close relation in degree of orientation and sintering shrinkage of the compact. The sintering shrinkage is simply obtained from dimensional measurement of green compacts and sintered ones. It is proposed that the saturation value of the sintering shrinkage is made to be evaluation criterion for deciding the strength of applied magnetic field in order to find the optimum condition in the magnetic field orientation forming. Though various factors affect the degree of orientation, it is possible to estimate as those accumulation effect by sintering shrinkage. This evaluation criterion is applicable in case of not only the dry compaction of Sr-ferrite powder under magnetic field but also the forming of the compound mixed with a MIM binder.View full abstractDownload PDF (369K) -
Kazuhiro Matsugi, Gen Sasaki, Osamu Yanagisawa2003 Volume 50 Issue 3 Pages 238-247
Published: March 15, 2003
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDistributions of the voltage and temperature were obtained during spark sintering, for punch-die-compact systems using compacts with two kinds of shapes, simple cylinder and two-step cylinder, and two kinds of powders, titanium as a conductor and alumina as an insulator. The voltage and temperature were calculated on the basis of Ohm's and Fourier's laws. The calculated voltage and temperature were in good agreement with those measured by a voltmeter and thermocouples, respectively. The calculated temperature distribution changed in the simple cylindrical compact system depending on the kind of powders, because of the difference in the amount of Joule's heat generation in the compacts due to the kind of powders. In contrast, for the two-step cylindrical titanium compact system, the temperature distribution was affected by the difference in the amount of the current density depending on the cross-sectional area.View full abstractDownload PDF (2005K)
- |<
- <
- 1
- >
- >|