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Volume 37, Issue 7
Displaying 1-8 of 8 articles from this issue
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Shigeo OYA1987Volume 37Issue 7 Pages 465-467
Published: July 30, 1987
Released on J-STAGE: July 23, 2008
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Takashi KUNIMOTO, Yuichi MATSUMOTO, Yukio DOI1987Volume 37Issue 7 Pages 468-472
Published: July 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSFor the purpose of improving the properties of materials by applying the prestrain method and to adapt these materials for the naval ships, the prestrain effects of the corrosion resistant aluminum alloy A5086 were investigated with respect to tensile strength, fatigue strength, hardness and influence of fatigue crack propagation induced by the stress concentration. The prestrain has a little effect under the condition occuring the stress concentration, however, the static strength and the fatigue strength are remarkably improved when the stress concentration is kept away.View full abstractDownload PDF (453K) -
Mitsuru ADACHI, Mineo GONDA1987Volume 37Issue 7 Pages 473-477
Published: July 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSModification of hypereutectic Al-Si-Mg alloys into which various combinations of P and Na had been added was studied at various casting temperatures and cooling rates. If Mg content is less than about 0.5% in Al-20%Si-0.015%P alloy, an increase in Na content results in crystallization of fine grained primary silicon crystals and fibrous eutectic silicon crystals. If Mg is more than about 1.3%, however, an increase in Na does not have such an effect. Simultanious addition of Na and P to AC9A containing about 1.5%Mg has little effect on improvement of mechanical properties.View full abstractDownload PDF (1189K) -
Shoji HOTTA, Katsushi SARUKI, Motoyuki NAKAMURA1987Volume 37Issue 7 Pages 478-482
Published: July 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSInstrumented Charpy impact tests were carried out on aluminum alloy castings solidified for various solidification times and T6 heat treated. The impact value is improved by T6 treatment in the castings solidified in a short time, but remains unchanged or lowers in those solidified in a prolonged solidification time 700 to 800s. The reason is that age-hardening proceeds notwithstanding a negligible change in eutectic Si shape. The impact value decreases with prolonging solidification time. Castings solidified for 700 to 800s have the impact value less than a half of those solidified for 20s. This is attributed to coarsening of eutectic compounds and an increase in microporosity.View full abstractDownload PDF (1077K) -
Shiro KOHARA, Shuji ASADA1987Volume 37Issue 7 Pages 483-489
Published: July 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSFour fabrication techniques for SiC whisker-aluminum composite materials; sintering-rolling, liquid phase hot extrusion, liquid phase hot pressing and pressure infiltration, were investigated. Among those techniques, the pressure infiltration yielded the most successful result. In the pressure infiltration method, SiC whisker preforms are produced previously and infiltrated with molten aluminum. The volume fraction of SiC whiskers in the fabricated composites depends on the apparent density of used preforms. Preforms with high density are obtained by repeated treating of ultrasonic stirring and filtering of SiC whisker slurry suspended in hexametaphospholic acid solution.View full abstractDownload PDF (926K) -
Nobuyoshi MURAKAMI, Toshio KOBAYASHI1987Volume 37Issue 7 Pages 490-495
Published: July 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSA simplified model is proposed to predict the solidification process in which granular grains solidify in aluminum alloys. A grain is assumed to be a sphere in which a number of small spheres "element spheres" whose diameter corresponds to the dendrite arm spacing. As the intergranular and interdendritic residual liquids are clearly distinguished in this model, fraction solid is classified into three different types, microscopic, macroscopic and apparent fraction solids. The interdendritic liquid flow will be limited to a smaller quantity than intergranular one. This model will be useful to analyze the solidification problem which is controlled by the intergranular residual liquid during solidification.View full abstractDownload PDF (787K) -
Tadakazu OHNISHI, Hideaki SHIOTA, Taichiro ITO1987Volume 37Issue 7 Pages 496-502
Published: July 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSAl-Li-Cu-Mg-Zr alloy was aged at temperatures from 160 to 250°C. Aging of the alloy at 160 to 200°C causes a two-step mode of hardening, but that at 250°C does a single-step mode. Changes in tensile strength and proof stress of the alloy aged at 180°C take a similar two-step mode. The maximum strength 54kg/mm2, density 2.50g/cm3 and specific strength slightly exceeding that of 7475-T6 are achieved. The elongation rapidly decreases in the initial stage of aging and remains about 10% even at the maximum strength state. The Young's modulus and specific modulus of the solution-heat-treated alloy are better than those of 7475 by about 15 and 29% respectively, but gradually decrease with prolonging aging. The notch-yield ratio exceeds 1.0 in whole aging states.View full abstractDownload PDF (1825K) -
Masuji UEMURA1987Volume 37Issue 7 Pages 503-513
Published: July 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (1547K)
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