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Volume 41, Issue 4
Displaying 1-12 of 12 articles from this issue
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Shuhei OHSAKI, Tsuneo TAKAHASHI1991 Volume 41 Issue 4 Pages 225-231
Published: April 28, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThree type Al-Li alloys (8090, 8091 and 2090) sheets were aged at 443K in various temper conditions, and evaluated for corrosion behavior and resistance to stress corrosion cracking (SCC) initiation in sodium chloride solution. The underaged alloys were susceptible to intersubgranular corrosion, apt to lead localized corrosion pits. The peak-aged alloys suffered from dimple type pitting, on alloy 8090 and alloy 8091 preferentially along subgrain and grain boundaries, and on alloy 2090 within grains also. The resistance to SCC initiation was in agreement with that to localized corrosion owing to intersubgranular corrosion, improved with increasing aging time, and ranked in the order of alloy 8090>alloy 2090>alloy 8091.View full abstractDownload PDF (2411K) -
Tsuneo SAGA, Shuji NAGAI, Eiichiro SATO1991 Volume 41 Issue 4 Pages 232-237
Published: April 28, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe turning machinability of two magnesium alloy bars, AZ31 and AZ80, was evaluated under various conditions using two types of cemented carbide tool, type 31 and type 33, with two rake angles, γ=6° and 12°. According to the results, there was no difference in the cutting resistance between the two samples for all cutting conditions. However, the cutting resistance was dependent on the cutting speed; it increased with the increase of feeding speed. Also, the feed force increased when a side cutting edge angle was applied. In both specimens, the actually machined surface roughness was smaller than the values theoretically calculated. Judging by the chip shape, the ease of processing was either good or acceptable except for the cases in which the feeding speed was small and the cutting speed was high.View full abstractDownload PDF (838K) -
Shigenori YAMAUCHI, Kenji KATO1991 Volume 41 Issue 4 Pages 238-244
Published: April 28, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe influence of precipitate dispersion in the core alloy on the erosion of brazing-sheets was investigated. Brazing sheets with various size distributions of precipitates were prepared using 3003 or 3003+Cu alloy cores and 4104 alloy claddings. These brazing-sheets were subjected to a vacuum brazing cycle after 0 to 20% cold rolling. The erosion behavior was discussed in terms of the recrystallization of the cores during brazing. The unrecrystallized cores with subgrain structures were found to suffer from the erosion. The number density of fine precipitates with the size up to about 0.1μm in diameter affected the recrystallization behavior and resultingly the erosion. The cores with large number of fine precipitates remained unrecrystallized even at brazing temperature and suffered from the erosion at cold-reduction up to 10 to 15% because the fine precipitates strongly retarded the recrystallization. The cores with small number of fine precipitates, however, recrystallized at reductions higher than 5 or 7%. Thus, these cores suffered from the erosion only at limited reductions from 2 to 5%.View full abstractDownload PDF (2067K) -
Isao ITOH, Yasuo OTOGURO, Keiji HASEGAWA, Tetuya YAMAGAMI, Hidenori MA ...1991 Volume 41 Issue 4 Pages 245-250
Published: April 28, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe effect of tin in aluminum on the diffusion weldability of Al2O3 and Al has been investigated. The welding treatment was carried out at 773K and 873K for 1.8ks, 3.6ks and 7.2ks under the pressure of about 2.0MPa in a vacuum of 0.1Pa. The addition of Sn released thermal stress which was introduced at and near the welding interface during cooling and resulted in the high shear strength of the welded joint. The addition of both tin and magnesium to aluminum showed the same shear strength as that of Al-Mg alloy, which is higher than that obtained by the single addition of tin.View full abstractDownload PDF (1059K) -
Su-gun LIM, Junichi KANEKO, Makoto SUGAMATA1991 Volume 41 Issue 4 Pages 251-257
Published: April 28, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSRapidly solidified flakes of 2024 and 2219 based aluminum alloys with combined addition of Fe and Ni were produced by atomizing the alloy melt and subsequent splat-quenching onto a water-cooled copper single roll. Consolidation of the flakes was done by cold pressing, vacuum degassing and hot extrusion at a reduction ratio of 25 to 1. The hardness of flakes and P/M materials increased with combined addition of Fe and Ni due to fine dispersion of a ternary compound FeNiAl9. Age hardenability of both 2024 and 2219 based alloys was decreased with addition of Fe and Ni. However, the decrease in age hardenability was more pronounced in 2219 based alloys. In 2024 based alloys, some amount of age hardenability was always remained. Tensile strength of P/M materials was higher for as-extruded materials than for T6-tempered ones. As-extruded P/M materials with 4 wt% addition of Fe and Ni showed tensile strength higher than 550 MPa in both 2024 and 2219 based alloys. High elastic modulus of 95 GPa was obtained for P/M materials of 2024 alloy with 4 wt% addition of Fe and Ni.View full abstractDownload PDF (1124K) -
Keizo SAKURAI, Katsushige ADACHI, Koichi OGAWA, Ralph NIBA1991 Volume 41 Issue 4 Pages 258-263
Published: April 28, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSIn drilling of soft materials such as aluminum, large burr is formed at the outlet of drilled holes. The burr causes problems in the automatic machining processes. In this study, an increased and decreased feed drilling, that is, an intermittent decelerated feed drilling was applied to aluminum. The burr morphology was examined as a function of the number of drilled holes of aluminum. Both the area and volume of the burr formed in the intermittent decelerated feed drilling was reduced to approximately 83 and 78% of those formed in the conventional drilling. The present drilling method was found to be effective to prevent burr formation.View full abstractDownload PDF (824K) -
Tsuneo SAGA, Shigeru IKEDA1991 Volume 41 Issue 4 Pages 264-269
Published: April 28, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSTurning machinability of a FRM composed of the ADC12 aluminum matrix and 10% volume fraction of Al2O3-SiO2 short-fibers was investigated under various cutting conditions using three types of sintered diamond bites with different rake angles. The result for the FRM was compared with that for the ADC12. Short-fibers in the shear zone of the FRM became the origin of the stress concentration and caused shear deformation during turning. The stress concentration led to the raised cutting ratio and shear angle and resulted in the reduction of the cutting resistance. The short-fibers were effective as chip breakers and produced favorable chip treatment characteristics. The finished surface was also favorable. Sintered diamond bites with negative rake angles were found to be effective in both the chipping and strength of the cutting edge for the difficult-to-work FRM which required intermittent cutting.View full abstractDownload PDF (1866K) -
Katsuaki SUGANUMA, Teruaki FUJITA, Genn SASAKI, Nobuyuki SUZUKI1991 Volume 41 Issue 4 Pages 270-275
Published: April 28, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSAn AC8A aluminum alloy matrix composite reinforced with 20vol% aluminum-borate whisker was fabricated by squeeze casting and its mechanical properties were evaluated. Tensile strength of the composite was about 430MPa and 250MPa at room temperature and 573K, respectively. The Young's modulus at room temperature was as high as 107 GPa, while the average thermal expansion coefficient between room temperature and 573K was as low as 14.5×10-6/K. The decrease in strength during exposure at up to 573K was small. The composite showed good heat-shock resistance for the heat cycle between room temperature and 673K. The properties of the obtained composite were found to be useful for the elevated temperature materials such as car engine components.View full abstractDownload PDF (1328K) -
Yasunori KOMATSU, Takanobu ITO, Takeo ARAI, Yasuo MURAOKA, Haruki ABE, ...1991 Volume 41 Issue 4 Pages 276-283
Published: April 28, 1991
Released on J-STAGE: October 30, 2008
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Tatsuji SHIMOKAWABE1991 Volume 41 Issue 4 Pages 284-293
Published: April 28, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (1033K) -
Shouzo MATSUDA1991 Volume 41 Issue 4 Pages 294-295
Published: April 28, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (293K) -
1991 Volume 41 Issue 4 Pages v
Published: 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (75K)
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