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Volume 36, Issue 2
Displaying 1-9 of 9 articles from this issue
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Shozo MATSUDA1986 Volume 36 Issue 2 Pages 61-63
Published: February 28, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (343K) -
Goroh ITOH, Hisashi SUZUKI1986 Volume 36 Issue 2 Pages 63-65
Published: February 28, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe ductility of Al-5mass%Mg alloy specimen at temperatures ranging from 473 to 673K has been examined, as a function of melting and annealing atmospheres. It was revealed that the ductility decreased at about 573K (high temperature embrittlement, HTE), when the oxidizing melting or annealing atmospheres were applied. However, second phases concerning oxygen were not detected in the specimen showing HTE. It was suggested that HTE was brought about by oxygen atoms dissolved in the matrix or segregated on grain boundaries.View full abstractDownload PDF (930K) -
Michitomo KATO, Yasukazu IKEUCHI, Tomoshi TAKAHASHI1986 Volume 36 Issue 2 Pages 66-71
Published: February 28, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe characteristics of the Al-10%Pb-4% bearig were studied mainly on effects of velocity and pressure of friction on the bearing performance. The coefficience of friction decreases with increasing pressure to some extend. The minimum value is below 0.05 and increases again at the pressure more than 15kg/cm. The maximum permissible PV value is about 1500kg/cm2•m/min and 2300kg/cm2•m/min at 1ton/cm2 and 1.5ton/cm2 of compacting pressure, respectively.View full abstractDownload PDF (2297K) -
Akihiko KAMIO, Hiroyasu TEZUKA, Tatsuo SATO, Than Trong Long, Tsuneo T ...1986 Volume 36 Issue 2 Pages 72-80
Published: February 28, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSAl-4mass%Fe and Al-7mass%Fe alloys were rapidly solidified into a ribbon shape at cooling rates about 105 and 106K/s by a single roller technique. The solid solubility of iron in aluminum extends up to 7.3mass% at a cooling rate about 106K/s. Angular-shaped and disc-shaped metastable phases are found in the alloys solidified at slightly lower cooling rates. Cell structure is observed in the alloys solidified at a rate about 105K/s. Dark field micrographs and diffraction rings show the cell boundary consisting of microcrystalline. In the decomposition process of supersaturated solid solution, three metastable phases form. Decomposition at temperatures up to 673K starts with the formation of angular-shaped metastable phase (diamond cubic, a=0.585±0.001nm). A disc-shaped metastable phase (f.c.c., a=2.406±0.001nm) precipitates on the {100} planes of the matrix coexisting with the angular-shaped one. Further annealing results in the formation of rod-shaped metastable phase (f.c.c., a=1.604±0.001nm) along the [100] direction of the matrix. A metastable phase Al6Fe forms at grain boundaries and transforms to stable Al3Fe at higher annealing temperatures.View full abstractDownload PDF (6088K) -
Kenzo KOBAYASHI, Kenichi SHIMIZU, Daisuke TERANISHI1986 Volume 36 Issue 2 Pages 81-88
Published: February 28, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe development, during anodizing, of γ'-alumina within the barrier oxide layer formed on aluminum covered with a thin thermal oxide layer is strongly influenced by the nature of anion species of the electrolytes. The development of γ'-alumina is strongly inhibited when the thermally oxidized aluminum specimens were anodized in such solutions as aqueous ammonium dihydrogen phosphate, ammonium tartrate and ammonium citrate, where anion species of the respective electrolytes are known to exhibit inward movement after they have been incorporated into the growing barrier oxide layer. In such cases, the fine crystals of γ-alumina, which are thought to act as nuclei for the amorphous to crystalline transformation, are likely present surrounded by the amorphous film material doped with anion species of the electrolytes. The strong inhibition for the development of γ'-alumina can be explained as being due to the presence of the incorporated anions which are known to hinder the structural rearrangement at the amorphous/crystalline boundary.View full abstractDownload PDF (1271K) -
Ken TOHMA1986 Volume 36 Issue 2 Pages 89-98
Published: February 28, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSElectrochemecal mesurements in NaCl solutions were carried out to understand the electrochemical informations during pitting growth process such as irreversibility of anodic polarization curves and variation of electrode potential with time in immersion corrosion test. In galvanostatic anodic dissolution, electrode potential rises to pitting potential immediately after current application and lower after a while. The time required for the beginning of the potential fall prolongs with increase of applied current. While the internal surface of the pits consists of a large number of crystallographic tunnels in the earlier stage of dissolution, they transform to dimples after sufficient potential fall. PH rapidly decreases and Cl- concentration increases with applied current in anodic area of electrolysis cell simulating localized corrosion. All the electrochemical informations for pitting growth are well understood in terms of the effect of anodic area increase as well as pH decrease and salt condensation within pits.View full abstractDownload PDF (2456K) -
Masakatsu SHIBATA, Seiki NISHI1986 Volume 36 Issue 2 Pages 99-104
Published: February 28, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSCrystallization and redissolution of giant intermetallic compounds in Al-4.5%Mg alloys containing 0.25%Cr were studied. Giant intermetallic compounds in those alloys crystallized at temperatures from 640°C to 680°C. The higher the crystallization temperature is, the larger the size is and the less the number is. The compounds redissolve so slightly in molten alloys and it takes an hour to dissolve even at 800°C. A giant intermetallic compound CrAl7 has micro-vikers hardness Hv 429 and density 3.12g/cm3.View full abstractDownload PDF (998K) -
Tuneyuki SUGIURA, Kanemichi IZUMI, Haruo SUZUKI1986 Volume 36 Issue 2 Pages 105-111
Published: February 28, 1986
Released on J-STAGE: July 23, 2008
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Yasuhiko MIYAKE1986 Volume 36 Issue 2 Pages 112-121
Published: February 28, 1986
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (1930K)
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