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Volume 43, Issue 9
Displaying 1-9 of 9 articles from this issue
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Sachiko ONO, Noboru MASUKO1993 Volume 43 Issue 9 Pages 447-452
Published: September 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDissolution behavior of the barrier layer of porous anodic films formed on aluminum after immersion in sulfuric acid has been studied using re-anodizing (pore-filling) technique. The higher a forming voltage is, the higher the dissolution rate of a film. The barrier layer of films formed in phosphoric acid was divided into three layers according as dissolution rate and was dissolved most rapidly in a middle layer. The defects were detected after the dissolution of an outer layer as fine pores which passed through the barrier layer. The volume of the defects increased with increasing forming voltage. In films formed in oxalic acid, however, no such defects as above but thickness unevenness were detected in the middle of the barrier layer which was divided into two layers. The dissolution rates of inner layers of films formed in two electrolytes at different voltages were low and almost same. The dissolution rate is suggested to depend on both contents of incorporated anions and defects.View full abstractDownload PDF (638K) -
Sachiko ONO, Noboru MASUKO1993 Volume 43 Issue 9 Pages 453-458
Published: September 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe structure and the dissolution behavior of porous anodic films formed on aluminum have been studied by electron microscopy with various techniques which include SEM, TEM, replica, ultramicrotomy and ion-thinning methods. Cell walls of films formed in oxalic acid were dissolved uniformly, whereas micro-pores in cell walls became clear after the dissolution of films formed in phosphoric acid. Long and narrow holes (the width of about 25nm) which passed through cell walls from triple cell junctions to the vicinity of pore walls were observed in an ion-thinned film formed in phosphoric acid. They were found locally in some cells and scarcely in outer layers. They were the cause of defects which had been detected by an electrochemical measurement after the dissolution of the outer layer of a barrier layer. Small voids on triple points were found in films formed both in phosphoric acid (size about 15nm) and oxalic acid (size about 2nm).It is shown that the ion-thinning is the most powerful technique to detect the unevenness of local and minute structure of porous films.View full abstractDownload PDF (2232K) -
Yoshihiro NAKAYAMA, Tetsuya TAKAAI, Masahiro KINOSHITA1993 Volume 43 Issue 9 Pages 459-464
Published: September 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSLow temperature absorbed energy of the cold rolled plate of 5083 aluminum alloy was investigated in view of the work hardening, laminated fracture and effect of isothermal annealing treatment. Side grooved specimens were applied in order to discuss the relation between the laminated fracture and the absorbed energy in detail. The results are summerized as follows; (1) Close relations were observed between the laminated fracture and the low temperature absorbed energy of the side grooved specimens. (2) Divisions of the lamination and related increases of the fracture surface area were seen in the specimens isothermally annealed under certain heating conditions. (3) Close relations between the precipitation of the intermetallic compound Al3Mg2 and the division of the lamination were supposed.View full abstractDownload PDF (1279K) -
Susumu IKENO, Katsuhiko HORIE, Kenji MATSUDA, Yasuhiro UETANI, Hiroshi ...1993 Volume 43 Issue 9 Pages 465-471
Published: September 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSAging behavior of alumina particle dispersed Al-Cu-Mg alloy composite materials containing various amount of alumina, was investigated by means of Vickers micro hardness test and transmission electron microscopy. GPB zone and S' intermediate precipitates were observed on aging at 423K in 2 vol%Al2O3/Al-Cu-Mg composite material, while GP zone and θ' intermediate precipitates appeared at the same aging condition in 6 and 8 vol%Al2O3/Al-Cu-Mg composite materials. A plolonged aging time was needed to reach a maximum hardness with increasing Al2O3 content. The maximum hardness decreased with increasing Al2O3 content in the case where the GPB zone and S'intermediate phases coexisted. On the other hand, in the case where GP zone and θ' intermediate phase coexisted, the values of maximum hardness were almost independent of Al2O3 content. At aging temperature of 473K, almost all precipitates were S' intermediate phase in 2 and 4 vol%Al2O3/Al-Cu-Mg composite materials. In these specimens, almost same and relatively shorter time was needed to reach a maximum hardness. While, in 6 and 8 vol%Al2O3/Al-Cu-Mg composite materials in which θ' intermediate phase exists, the maximum hardness values were lowered and longer aging time was needed.View full abstractDownload PDF (2252K) -
Toshiro KOBAYASHI, Mitsuo NIINOMI, Michimasa YAMAOKA, Toshihiro HARATA ...1993 Volume 43 Issue 9 Pages 472-477
Published: September 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe effect of strontium (Sr) modification on the fracture characteristics is investigated in high purity Al-Si-Mg type casting alloy, AC4CH. The Charpy absorbed energy, static fracture toughness and dynamic fracture toughness of AC4CH are improved by the addition of Sr associated with the refinement and spheroidizing of needle like eutectic Si, which results in the relaxation of stress concentration of the eutectic Si. The cohesion of eutectic Si and porosity increase with increasing Sr addition. The larger size eutectic Si particles increase again with increasing Sr addition over 50ppm. These three factors seem to be the causes for decreasing dynamic toughness of AC4CH at 200ppm Sr addition comparing with 100ppm Sr addition.View full abstractDownload PDF (802K) -
Shoichi SATO, Minobu SUKIMOTO, Shuji ITONAGA, Tadatoshi HONDA1993 Volume 43 Issue 9 Pages 478-483
Published: September 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe fatigue life distribution of the brazing butt joint consisted of D712.0 and A6063 alloys were analyzed statistically, in order to evaluate reliability and strength characteristics of air intake manifold (AIM) made by brazing joint of cast and wrought aluminum alloys. Obtained results are summarized as follows;
(1) Fatigue life distribution of the brazing joint is scattered according to the normal distribution.
(2) Scatter of fatigue life seems to be influenced by brazing defect ratio, filler metal microstructure and joint force with base metals.View full abstractDownload PDF (1489K) -
Kikyung SONG, Hidetoshi FUJII, Hideo NAKAE, Hideki YAMAURA1993 Volume 43 Issue 9 Pages 484-489
Published: September 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe effect of Sr content and solidification rate on the morphology of the Si phase in the Al-Si eutectic alloy were investigated using a unidirectional solidification method. A critical quantity of Sr for the modification was found between 0.004 and 0.07mass%. When more Sr than the critical quantity was added, the Si phases were modified at a solidification rate of R ≤ 4mm/h, while the Si phases were coarsened at a solidification rate of R ≥ 2mm/h. When the solidification rate is very low, any addition of Sr coarsens the Si phase without modification effect. The reduction of Si/liquid interfacial free energy by addition of Sr allows Si phase to grow with an instinctive shape as the leading phase. In these circumstances, the adsorption of Sr on Si phases plays an essential role. That is, when the solidification rate is very low, adsorbed Sr can not prevent Si phase from growing and therefore Si phase becomes coarse. On the other hand, when the solidification rate is high, adsorbed Sr prevents Si phase from growing on the fastgrowing faces and the Si phase is modified.View full abstractDownload PDF (1536K) -
Hiroshi SAKUTA1993 Volume 43 Issue 9 Pages 490-500
Published: September 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (1325K) -
Shigeoki SAJI1993 Volume 43 Issue 9 Pages 501-502
Published: September 30, 1993
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (166K)
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