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Volume 38, Issue 2
Displaying 1-10 of 10 articles from this issue
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Hajime YAMADA, Takio TANAKA1988 Volume 38 Issue 2 Pages 71-76
Published: February 29, 1988
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSChromium has no remarkable effect on recrystallization process and resultant grain size of Al-1%Mg-0.6%Si and Al-3%Mg alloys. However, it has a notable effect of retarding grain growth, and an addition of about 0.3% of Chromium to these alloys remarkably decreases the grain growth at high temperatures. This effect of Chromium is due to the primary inclusion particles. Growth rate of recrystallized grain decreases with decrease in the inter-particle spacing.View full abstractDownload PDF (1106K) -
Tomoaki YAMANOI, Masashi SAKAGUCHI, Minoru HASEGAWA1988 Volume 38 Issue 2 Pages 77-83
Published: February 29, 1988
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSGrain size and texture after recrystallization in Al-1.2%Fe-0.03-0.5%Si alloy foils (100μm in thickness), aged at R. T.-773K between cold rolling and finally annealed at heating rateof 0.1, 200, over 1000K/s, have been investigated experimentally. At high silicon contents, heating rate in final annealing has little effect on grain size and recrystallized structures of R or R+cube texture are observed. A decrease in silicon content, however, causes coarse grains in rapid heating and texture near (001)[310]. The texture is obtained by rotating (311)[233] component of surface layer formed in cold rolling by approximately 40 degree rotation around <111> axes. For thinner material such as foil, when growth rate of grains is large, recrystallized structures are influenced strongly by the surfaces tructure before recrystallization.View full abstractDownload PDF (935K) -
Masashi SAKAGUCHI, Tomoaki YAMANOI, Minoru HASEGAWA1988 Volume 38 Issue 2 Pages 84-90
Published: February 29, 1988
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSRelation between tensile properties and recrystallized structure has been studied in Al-1.2%Fe-0.003-0.5%Si alloy foils of 100μm thickness which were prepared at various aging temperatures and heating rates in final annealing. The strength and elongation of the foils decrease with decreasing ratio of thickness to recrystallized grain size t/d. When t/d is larger than 5 or 6, the uniform elongation (true strain ε) is equal to the n-value of the material. For foils of 40 to 100μm in thickness, the relation between ε/n and t/d is given by a same equation. However, for thinner foils, the elongation becomes smaller than n. The decrease in elongation with increasing grain size is closely related to the development of surface roughness with plastic strain. In relation between texture and elongation, strong R-texture is not preferable to R-+cube-texture because of lower n value.View full abstractDownload PDF (916K) -
Kenzo KOBAYASHI, Ken-ichi SHIMIZU1988 Volume 38 Issue 2 Pages 91-95
Published: February 29, 1988
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSElectropolished aluminum specimens were heat-treated in air at 550°C for 15min to form a thin layer of thermal oxide containing γ-alumina crystals with sizes up to about 0.2μm. The thermally oxidized specimens were then anodized to 100V in 0.1M ammonium pentaborate solution at 20°C with a constant current density of 5mA/cm2. The structure of the 100V films were examined by transmission electron microscopy of ultramicrotomed sections with special attention to the behavior of γ-alumina crystals during anodic oxidation. Where γ-alumina crystals were present, aluminum surface exhibited ridged appearance. Above the ridges, thin platelets of γ-alumina were observed in direct contact with the metal. No significant film formation was observed at the surface of γ-alumina crystals or at the crystal/metal interface. A band of γ'-alumina with wedge-shaped cross section was observed clearly to extend into the barrier oxide layer grown over aluminum surface surrounding γ-alumina crystals.View full abstractDownload PDF (1045K) -
Tetsuichi MOTEGI, Atsumi OHNO1988 Volume 38 Issue 2 Pages 96-101
Published: February 29, 1988
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSIn order to understand the solidification mechanism of Al-Si and Al-Ge alloys, in-situ observation of the solidication phenomena on the molten surface has been carried out during unidirectional solidification. In hypoeutectic alloy containing 8 to 10mass% Si or 46 to 51mass% Ge, eutectic solidification starts at the cooling end and then unidirectionally proceeds independently of the primary crystal of α aluminum dendrites which exists in the eutectic melt. In eutectic compositions containing 11.7mass% Si or 53mass% Ge, only unidirectional solidification of eutectic occurs. In this case, eutectic Si or Ge crystals are always observed to precede at the competitive growth with eutectic aluminum. These phenomena show that the silicon and germanium are the leading phases of the eutectic in these alloys. In hypereutectic composition containing 14 to 18mass% Si or 55 to 60mass% Ge, eutectic solidification starts on primary crystals of angular silicon or germanium and then spreads radially in the melt. These results are consistant with those previously obtained on Al-Cu, Al-Ni, Zn-Al and Sn-Zn eutectic alloys.View full abstractDownload PDF (3066K) -
Naotsugu INAKAZU, Hirofumi INOUE, Yasuyuki KANENO1988 Volume 38 Issue 2 Pages 102-106
Published: February 29, 1988
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe correlation between the texture and the mechanical properties has been investigated on an extruded aluminum alloy 6061 by determining the orientation distribution function (ODF) and measuring various mechanical properties. The parts having complex cross section are composed of the <100> fiber texture accompanied with the {001} <100> and {011}<100> components, and their tensile strength is highest in all parts studied, because of the strengthening effect of the <100> fiber axial component. The parts having flat cross section are composed of the cubic texture like the mosaic with misorientation angle of about 10 degrees and ductile for the tensile stress, because these parts have a tendency to rotate about the <100> axis parallel to the tensile axis and thus are inferior to the other parts in the tensile strength.View full abstractDownload PDF (780K) -
Michihiro TAGAMI, Tatsuo OHTANI, Tadashi USAMI1988 Volume 38 Issue 2 Pages 107-113
Published: February 29, 1988
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSEffects of heat treatment, contents of Cu and Mg, and rolling reduction on the damping capacity, tensile strength, hardness and elongation were studied for Zn-22% Al alloys. Damping capacity of the alloys was measured in terms of internal friction using the inverted torsion pendulum method at frequency of 1 to 3Hz in atmosphere. The alloy heat-treated at 360°C for 2hrs followed by water quenching exhibits the highest internal friction (Q-1, 4.5×10-2). Aging at 250°C for 1hr results in about 38% decrease in the value of internal friction. Addition of 0.021%Mg lowers the internal friction of as-cast alloys containing 0.3%Cu by about 50%, whereas addition of 0.3%Cu has little effect on the internal friction of as-cast alloys (Q-1, 1.1×10-2). Addition of 0.3%Cu and 0.3%Cu, 0.021% Mg cause a decrease in internal friction of heat-treated alloy by about 33% and 68%, respectively. Rolling reduction of 80% results in the improvement of internal friction of heat-treated alloy containing 0.3%Cu and 0.008%Mg by 30%. Cu and Mg addition increases the tensile strength and hardness of heat-treated alloys. Simultaneous addition of 0.3%Cu and 0.008%Mg decreases elongation to the range of 1%, while addition of 0.3% Cu has no effect on the elongation of the heat-treated alloys.View full abstractDownload PDF (2261K) -
Yasuhiko ITOI, Satoshi KAMBE, Eiichi SATO1988 Volume 38 Issue 2 Pages 114-117
Published: February 29, 1988
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe-effects of temperature on corrosion resistance of 99.99% aluminum and aluminum alloys in aqueous solution of sodium chloride were examined. The weight loss showed a maximum at 40°C. Polarization behavior of 99.99% Al changed from cathodic controlled type to anodic controlled one with increasing temperature. Pseudo-boehmite film formed at 80°C, resulting in the inhibition of corrosion of aluminum in the solution containing chloride ion.View full abstractDownload PDF (1012K) -
Toshihiro CHIKADA1988 Volume 38 Issue 2 Pages 118-125
Published: February 29, 1988
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (1382K) -
Taichi SATO1988 Volume 38 Issue 2 Pages 126-128
Published: February 29, 1988
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (573K)
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