Journal of Japan Institute of Light Metals

Production of Al-12mass%Si alloy rapidly solidified clad strip by melt drag process

Shinsuke SUZUKI, Toshio HAGA, Mitsugu MOTOMURA

1995 Volume 45 Issue 12 Pages 685-690
Published: December 30, 1995
Released on J-STAGE: October 30, 2008

DOIhttps://doi.org/10.2464/jilm.45.685

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This study was attempted to produce rapidly solidified clad strip by a melt drag process and to examine the clad strip properties. Roll speed V and cooling length L were chosen as principal producing factors. Clad strips consisting of base and overlay strips rigidly bonded with clear bonding interface are produced under the condition where roll speed V was varied from 30 to 70m/min and cooling length L was varied from 25 to 100mm. Clad strips of base and overlay strip both rapidly solidified are produced by cooling length between 75 and 100mm with a constant rolling velocity 50m/min.

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Internal friction of Al alloys produced by mechanically alloying

Ken-ichiro HARA, Reiko KOJIMA, Takao ENDO

1995 Volume 45 Issue 12 Pages 691-696
Published: December 30, 1995
Released on J-STAGE: October 30, 2008

DOIhttps://doi.org/10.2464/jilm.45.691

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Internal friction was measured of four mechanically alloyed aluminum alloys in a range of temperature from 300 to 700K at a frequency of about 1Hz. Peaks are observed at about 450K, at much lower temperature than that of pure aluminum produced by ingot metallurgy. The shift of the temperature is ascribed to the small grain size produced by mechanical alloying. The peak height of IN9052 (Al-4.0 mass%Mg) and IN9021 (Al-1.5 mass%Mg-4.0 mass%Cu) alloys, which exhibit superplasticity, is 6 to 10 times greater than that of the other alloys which fail to exhibit superplasticity. This fact is explained by the difference in the mobility of grain boundary among these alloys. Based on these facts, the conclusion has been drawn that the internal friction ascribable to grain boundary sliding can be a good measure to find structures feasible to superplasticity.

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Study of purification parameters in vacuum distillation of magnesium

Makoto INOUE, Shigeharu KAMADO, Yo KOJIMA

1995 Volume 45 Issue 12 Pages 697-701
Published: December 30, 1995
Released on J-STAGE: October 30, 2008

DOIhttps://doi.org/10.2464/jilm.45.697

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This study of purification parameters in vacuum distillation of magnesium was performed using primarily AM100 magnesium alloy as the raw material. The ratio of purification increases with increasing purification time in the AM100 magnesium alloy and is higher than the ratio of purification of the pure magnesium. The ratio increases with increasing purification temperature in the AM100 and AM60 magnesium alloys. The compositions at the AM100 alloy are almost the same after purification at temperatures 555°C, 600°C and 625°C. By a hole type condenser, quantities of impurities of the distilled pure magnesium inside and outside the condenser are about the same. The Zn concentrations of the purified AM100 and AM60 alloys are, however, more inside than outside the condenser. Pure magnesium of less than 30ppm Zn can be converted to pure magnesium of 10ppm Zn by the vacuum sublimation method.

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Workability, heat treatment characteristics and mechanical properties of Mg-Li-Al and Mg-Li-Zn ternary alloys

Hidenori HATTA, Zaizhe LI, Shigeharu KAMADO, Yo KOJIMA

1995 Volume 45 Issue 12 Pages 702-707
Published: December 30, 1995
Released on J-STAGE: October 30, 2008

DOIhttps://doi.org/10.2464/jilm.45.702

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Aluminum or zinc was added by 10 mass% to Mg-20, 25 and 30 mass%Li alloys to develop a material with high specific strength and good cold-workability. Influences of aluminum and zinc on their cold-workability, heat treatment characteristics and tensile properties were investigated. The addition of zinc improves cold-workability and ductility and, therefore, even a Mg-20 mass%Li system alloy is able to be rolled to a rolling reduction of 90% without cracks. Aluminum- or zinc-added alloys harden by the quenching from temperature higher than 150°C. Particularly, aluminum-added alloys have a large increment of hardness by quenching from temperature over 300°C. The hardening may be concluded to be caused by an increase of amount of aluminum solubility in lithium solid solution, because results of X-ray diffraction analysis show that the height of diffraction peaks of AlLi and Al₄Li₉ compounds is lowered and a lattice parameter of lithium solid solution decreases by the quenching. Aluminum-added alloys quenched from a temperature of 300°C, therefore, have higher tensile strength than the as-rolled specimens. Furthermore, a Mg-20 mass%Li-10 mass%Al alloy shows an age hardening at room temperature probably due to the spinodal decomposition.

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Behavior of impurities during distillation and melting of pure magnesium

Kouji KAITOH, Tetsuichi MOTEGI, Eiichirou SATOH

1995 Volume 45 Issue 12 Pages 708-712
Published: December 30, 1995
Released on J-STAGE: October 30, 2008

DOIhttps://doi.org/10.2464/jilm.45.708

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In order to understand the contamination of molten pure magnesium by various crucibles, at first 99.9% magnesium was distilled under reduced pressure conditions. Then the distilled magnesium was melted in the magnesia, alumina, zirconia with Y₂O₃, calcia, low carbon steel and stainless steel crucibles in an argon gas atmosphere. The Zn, Al, Si and Mn in the pure magnesium were effectively eliminated by the distillation. Melting in the magnesia, zirconia and SUS430 stainless steel crucibles makes no change of impurities. When alumina and low carbon steel crucibles are used, however Al and Fe contents increase by melting, because the alumina crucible and FeO or Fe in the low carbon steel crucible are reduced or attacked by the molten magnesium. Furthermore, Ca and Al contents increase by melting in the calcia crucible. It is confirmed by an X-ray diffraction method that the calcia crucible contains Ca(OH)₂ and Al₂O₃. Therefore, it is considered that the Ca(OH)₂ decompose and dissolve into the molten magnesium and the Al₂O₃ is reduced by the molten magnesium.

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Produce of manganence-type chemical conversion coatings for magnesium alloys and their corrosion resistance

Matsufumi TAKAYA

1995 Volume 45 Issue 12 Pages 713-718
Published: December 30, 1995
Released on J-STAGE: October 30, 2008

DOIhttps://doi.org/10.2464/jilm.45.713

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This paper describes a chromium-free conversion coatings for magnesium alloys. Manganence-type chemical conversion coatings were studies as a corrosion resistance for magnesium alloys. The structure of chemical conversion coatings were investigated by using XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy) and GDS (glow discharge spectroscopy). Corrosion resistance of chemical conversion coatings was evaluated in salt immersing spraying. Chemical conversion coatings consist of a film that is composed mainly of MnO₂ and partly of Mn₂O₄, Mn₂O₃ and MnOOH. It was found that these films formed composit coating. Concentration of KMnO₄ in bath for conversion coating formed on magnesium alloy was much lower than that for chromating process. Corrosion resistance of manganence-type chemical conversion coatings was comparable with that for chromating.

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Analysis of solidification process in aluminum semicontinuous casting slab by monitoring the mold temperature

Masanori TSUNEKAWA, Koushi NAGAE, Nobuyuki MUTOU, Norifumi HAYASHI, Te ...

1995 Volume 45 Issue 12 Pages 719-723
Published: December 30, 1995
Released on J-STAGE: October 30, 2008

DOIhttps://doi.org/10.2464/jilm.45.719

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For analysis of solidification process in aluminum semicontinuous slab casting, temperature at 78 different points of the mold were measured continuously for the several casting conditions. At the initial stage of casting, solidification shell formation and bowing on slab narrow face could be monitored by mold temperature. At the steady state, the amount of thermal transfers from slab to mold on many mold positions could be calculated from the measured mold temperature. The temperature of molten metal near the meniscus and the slab cooling rate near the slab surface which were related to slab surface quality, could also be estimated by mold temperature. Moreover, a sign of metal break out was successfully detected by monitoring mold temperature.

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Recollections of half century related to aluminum

Hajime YAMADA

1995 Volume 45 Issue 12 Pages 724-725
Published: December 30, 1995
Released on J-STAGE: October 30, 2008

DOIhttps://doi.org/10.2464/jilm.45.724

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The 1st International Conference on Casting & Solidification of Light Alloys

Kojiro F. KOBAYASHI

1995 Volume 45 Issue 12 Pages 726
Published: December 30, 1995
Released on J-STAGE: October 30, 2008

DOIhttps://doi.org/10.2464/jilm.45.726

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[title in Japanese]

1995 Volume 45 Issue 12 Pages 727-730
Published: December 30, 1995
Released on J-STAGE: October 30, 2008

DOIhttps://doi.org/10.2464/jilm.45.727

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Erratum to : Effect of rare earth elements on microstructures and tensile properties of alumina short fiber reinforced Mg-4 mass%Zn alloy composites

1995 Volume 45 Issue 12 Pages ix
Published: 1995
Released on J-STAGE: October 30, 2008

DOIhttps://doi.org/10.2464/jilm.45.12_ix

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