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Volume 58, Issue 7
Displaying 1-6 of 6 articles from this issue
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RESEARCH REPORT
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Michihide Yoshino, Masakazu Edo, Masami AsanoArticle type: Research Report
2008 Volume 58 Issue 7 Pages 279-284
Published: July 30, 2008
Released on J-STAGE: August 30, 2008
JOURNAL FREE ACCESSRelation between sacrificial anode effect and corrosion resistance of fin stock for automotive heat exchangers has been investigated on Al–Mn–Zn alloys by SWAAT. Corrosion depth of tube diminished, in contrast, corrosion loss of fin increased with increasing Zn content in the alloy. Total corrosion mass loss of fin stocks was separated into mass loss due to sacrificial anode and self corrosion, respectively, by immersion corrosion test. Rate of mass loss due to self corrosion to the total was 30 to 50%, independently of Zn content of fin stocks. The results were discussed with electrochemical polarization curves. It was concluded that corrosion loss of fin stock is minimized by the optimization of Zn content according to necessary sacrificial anode effect.View full abstractDownload PDF (2201K) -
Hidetoshi Uchida, Hideo YoshidaArticle type: Research Report
2008 Volume 58 Issue 7 Pages 285-289
Published: July 30, 2008
Released on J-STAGE: August 30, 2008
JOURNAL FREE ACCESSThe effects of the Si content on the elongation and bendability of Al–Mg–Si alloy sheets were investigated. The elongation increased with the Si content to 1.1%. The Work hardening exponent (n value) of the Al–Mg–Si alloys was calculated on the basis of true stress–true strain curves. The n value of the Al–Mg–Si alloy increased to a maximum value and then decreased with strain. The decreasing rate of the n value after the maximum n value of the low Si alloy was higher than that of the high Si ones. It is postulated that the decreasing rate caused the difference in the elongation. In the case of the low Si alloy, the n value decreased with strain at the true strain of 0.08 and micro-bands were observed in the TEM structures. It is considered that the micro-bands of the low Si alloy were more easily formed than those of the high Si ones. The bendability was inferior as the Si content increased. The high Si alloy contained large second phase particles which caused micro-voids during the bending operation. The micro-voids would be initiation sites of cracks and caused inferior bendability. It has been reported that the bendability is influenced by the second phase particles and formation of the share band. In this investigation, the second phase particle was the main reason for the inferior bendability rather than the formation of the share band.View full abstractDownload PDF (3233K) -
Hidetoshi Uchida, Hideo YoshidaArticle type: Research Report
2008 Volume 58 Issue 7 Pages 290-294
Published: July 30, 2008
Released on J-STAGE: August 30, 2008
JOURNAL FREE ACCESSThe effects of the n value and dislocation structures on the elongation of aluminum alloy sheets were investigated. The n value of the aluminum alloy was not constant. It increased to the maximum n value and decreased with strain. When the n value was constant, dislocation cell structures were observed. When the n value decreased, microbands were observed. It was considered that an increasing n value denoted an increasing dislocation density and a decreasing n value denoted a dynamic recovery occurring such as the formation of microbands. The decreasing rate after the maximum n value was a more important parameter than the average or the maximum n value for the relationship with the elongation. The Al–Mg–Si alloys and the Al-low Mg alloys had a highly decreasing n value rates. The pure aluminum and Al-high Mg alloys had low decreasing n value rates. It was considered that the highly decreasing rate after the maximum n value suggested a dynamic recovery and easily occurring local necking.View full abstractDownload PDF (2758K) -
Hirokazu Shimada, Futoshi Kido, Tetsuichi MotegiArticle type: Research Report
2008 Volume 58 Issue 7 Pages 295-298
Published: July 30, 2008
Released on J-STAGE: August 30, 2008
JOURNAL FREE ACCESSExperiments for casting AZ31B magnesium alloy sheets were performed in a semisolid continuous casting process. The semisolid slurry was produced using an inclined cooling plate, and the sheet was continuously cast by a twin roll caster. The casting sheet width was influenced by the roll speed, amount of semisolid slurry fed into the twin rollers, and the nozzle angle of inclination to the lower roll. The widest sheet was obtained at a 21.5 m/min rolling speed , a −5 degree nozzle inclination angle, and 10.2×10−3 m3/min of slurry. The sheet surface was smooth, and granular grains appeared throughout the sheet.View full abstractDownload PDF (1470K) -
Dai Nakama, Kazuyoshi Katoh, Hiroshi TokisueArticle type: Research Report
2008 Volume 58 Issue 7 Pages 299-304
Published: July 30, 2008
Released on J-STAGE: August 30, 2008
JOURNAL FREE ACCESSFriction surfacing of 6061 aluminum alloy plate by 6061 aluminum alloy bar filled with alumina particle as consumable rod, were done using a numerical control full automatic friction welding machine. Effect of the filling state of the alumina particle in a rod on the dispersion characteristic of the alumina particle in deposit was investigated. The scattering of the alumina particle was observed on appearance of the substrate clearly, but the shape of deposit was similar to the deposit without alumina particle. Regardless of the number of holes in rod, the surfacing efficiency increased with increasing surfacing speed. In addition, the surfacing efficiency of deposit with friction pressure 20 MPa showed higher value than that of the surfacing efficiency of deposit with friction pressure 25 MPa. But the difference of surfacing efficiency by the surfacing speed was small. The surfacing efficiency was decreased with increasing the number of holes in rod. As for the alumina particle, it was dispersed in a surface layer of deposit and the interface region near the substrate was stratified. The distribution of the alumina particle was stratified on central part of deposit and an intermediate part with RS side in deposit with 1HC rod which filled up an alumina particle centrally of the rod, and there was a little distribution to the other parts. Except the central part of the deposit, the existence of the alumina particle in deposit with 1H rod was identified, and it was dispersed in AS side in comparison with RS side comparatively uniformly. The distribution density of the alumina particle of the deposit with 2H and 4H rod showed a similar tendency to the deposit with 1H rod. However, the distribution density of deposit became larger in order of 1H, 2H, 4H. Wear resistance of 6061/6061 deposit was the lowest of all regardless of friction speed. Wear resistance of the deposit which dispersed alumina particles was improved in comparison with both substrate and 6061/6061 deposit, and it become larger in order of 4H, 2H, 1H.View full abstractDownload PDF (3563K)
REVIEW
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Teiichi AndoArticle type: Review
2008 Volume 58 Issue 7 Pages 305-311
Published: July 30, 2008
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (3791K)
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