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Volume 53, Issue 10
Displaying 1-7 of 7 articles from this issue
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RESEARCH REPORT
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Mika KAWAI, Takeshi SHINODA2003 Volume 53 Issue 10 Pages 405-409
Published: 2003
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSAluminum alloy castings have been widely used for auto parts. However they suffer from some defects such as porosity, segregation and others. Fusion processes used to modify the surface locally, lead to secondary defects like porosity and cracking in modified zone. In this research, a new surface modification process, which utilizes FSW phenomenon, is developed for modifying the large and flat surface layer of cast aluminum alloy. It is named as Friction Thermomechanical Process (hereafter referred as FTMP). This one is categorized as solid-state process and required no additional filler materials. The coarse microstructure in as-cast alloy surface is continuously refined due to dynamic recrystallization during FTMP. Defects in the cast are eliminated in the surface zone of 2 mm in depth. Modification area is extremely extended by use of offset pined tool, resulting in enhanced stirring metals.View full abstractDownload PDF (567K) -
Takayoshi FUJINO, Takuya NARA2003 Volume 53 Issue 10 Pages 410-415
Published: 2003
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSPhotocatalyst has recently been investigated miscellaneously in association with environmental concerns. TiO2 has especially been subject for a wide range of researches, because of its stability and harmlessness to environm studies have been made to improve photocatalytic activity by formation of TiO2 with improved crystallinity, TiO2 with carrier metal and TiO2 with a wider surface area. The purpose of this study is to improve photocatalytic activity with increasing of surface area and providing carrier metal, where aluminum was used for base of TiO2 film. TiO2 film was prepared on porous aluminum anodic oxidation film having a wide surface area. TiO2 film was prepared also on electrolytically colored anodic oxide coatings of nickel and silver. Photocatalytic activities were examined by decomposition rate of malachite green. It was found that, the base of Na3PO4 anodizing films shows higher photocatalytic activity than that of H2SO4 anodizing films, due to a larger amount of TiO2. The best photocatalytic activity took place on both films when the film thickness was 4μm. Photocatalytic activity of TiO2 films on electrolytically colored anodic oxide coatings on nickel and silver were improved since deposit by secondary electrolysis acts as carrier metal. It was indicaed from the above result, that electorolytically colored anodic oxide coatings are effective as base of photocatalyst films, and higher photocatalytic activity will be expected by carrying out electrolytic bath of anodic oxidation film, adequately selecting of deposit metal and controlling the amount of deposit metal.View full abstractDownload PDF (510K) -
Takao YAMAZAKI, Kazutaka MIKI, Unkai SATO, Mototaro SATO2003 Volume 53 Issue 10 Pages 416-420
Published: 2003
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSIn the metal cutting, cutting oil is generally used for lubrication, cooling, chip disposal. However, for the cutting oil, sulfur, chlorine, etc. are included, and the work environment deteriorates. Therefore, it is an ideal that it dose not use the cutting oil. This study described titanium base alloy on cooling air cutting which did not use cutting oil. Dry, MQL cutting were carried out as a cutting mode for the comparison, and cutting force, tool wear, surface roughness, cutting mechanism such as the chip shape were compared and were examined. As the result, the cutting force lowered in comparison with the dry-type cutting, and it was equivalent to the MQL cutting. And, on die tool wear, it was also equivalent to the MQL cutting, and it was effective of the cooling air cutting. However, the effect of which cooling air cutting on surface roughness and chip shape was remarkable could not be observed. Cooling air cutting of the titanium base alloy it synthetically judged it, it was under limited cutting condition, and it clarified the effectiveness.View full abstractDownload PDF (497K) -
Kazuhiko NAKAMURA, Masami NAKAMURA, Atsuyoshi TAKAHASHI, Shunro YOSHIO ...2003 Volume 53 Issue 10 Pages 421-426
Published: 2003
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSThe characteristic of the annealing of a pure aluminum sheet by the CW-CO2 laser is examined. It is necessary to select a suitable laser irradiation condition to generate a full annealed part through the rear surface of the sheet. The irradiation conditions were the output of laser, the defocus distance from the focal point and the traverse speed of sample. The temperature necessary to acquire full annealing by the laser irradiation method is 1.4 times higher than that of the electric furnace method. The full annealing width estimated from the hardness distribution on the bottom surface spreads with higher output and larger defocus length, or smaller traverse speed. The minimum value of full annealed width is restricted by the appearance of molten part in the laser irradiated area. The maximum and minimum widths of full annealed region obtained under this experimental condition are 12.5 and 2.5 times larger than the thickness of sheet, respectively. By choosing suitable laser conditions, the annealing can proceed easily in the limited zone. However, it is difficult to keep the full annealed width to be constant. The full annealed width of the prescribed length might not be obtained until the temperature distribution reaches the steady state. On the other hand, the full annealed width extends at the final stage where the laser approaches the edge of the sheet due to the heat insulation effect of the edge. Therefore, the uniform width should be realized by controlling the condition such as the laser output, the defocus length and the traverse speed during laser irradiation.View full abstractDownload PDF (482K) -
Makoto KOBASHI, Shinya TANAHASHI, Naoyuki KANETAKE2003 Volume 53 Issue 10 Pages 427-432
Published: 2003
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSFoamed Aluminum (highly porous Aluminum) was fabricated by powder processing technology. Aluminum (pure Al or Al–7Si alloy) and titanium hydride (TiH2) powders were mixed to prepare a precursor. The Al(–7Si)/TiH2 precursor was consolidated by three different methods (cold compaction, hot compaction and hot extrusion). The hot compaction and hot extrusion temperatures were 673 and 773 K, respectively. The cold compaction pressures were 450 MPa and 800 MPa, and the hot compaction pressure was 160MPa. The Al(–7Si)/TiH2 precursor was heated in an infrared furnace to melt aluminum and to decompose TiH2, which resulted in the H2 gas generation in molten aluminum. In this work, effects of some processing parameters (heating temperature, heating duration, heating rate and aluminum powder composition) on the foaming behavior were investigated. Heating temperature should be in an adequate range. When the heating temperature was low, the precursor did not expand sufficiently. On the other hand, when the heating temperature was high, the precursor shrunk rapidly. The heating rate did not affect the foaming behavior significantly within the present experimental ranges (0.12~0.5K·s−1). When the Al–7Si/TiH2 precursor was heated, the maximum expansion was sustained for a certain period of time, whereas the Al/TiH2 precursor shrunk rapidly.View full abstractDownload PDF (659K)
REVIEW
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Shinichi YAMORI, Yasunori NAGAYOSHI2003 Volume 53 Issue 10 Pages 433-435
Published: 2003
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSDownload PDF (225K)
LECTURE
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Kimio Nakamura2003 Volume 53 Issue 10 Pages 436-443
Published: October 30, 2003
Released on J-STAGE: June 30, 2021
JOURNAL FREE ACCESSDownload PDF (855K)
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