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Volume 37, Issue 10
Displaying 1-11 of 11 articles from this issue
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Shiro KOHARA1987 Volume 37 Issue 10 Pages 637-638
Published: October 30, 1987
Released on J-STAGE: July 23, 2008
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Yoshinobu TAKEDA1987 Volume 37 Issue 10 Pages 639-645
Published: October 30, 1987
Released on J-STAGE: July 23, 2008
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Osamu IWAO1987 Volume 37 Issue 10 Pages 646-655
Published: October 30, 1987
Released on J-STAGE: July 23, 2008
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Shigeo TSUCHIDA1987 Volume 37 Issue 10 Pages 656-664
Published: October 30, 1987
Released on J-STAGE: July 23, 2008
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Shouichi OCHIAI, Manabu UENO, Yo KOJIMA, Kazuki TAKASHIMA, Hisayoshi K ...1987 Volume 37 Issue 10 Pages 665-669
Published: October 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSA new type atomization technique for aluminum powders is proposed. In this process, the bubbles produced by the ejection of Ar gas into molten metal atomize it to fine liquid particles, which reach upper rotating disk cooled with liquid N2, and are crushed into the finer solid particles. The obtained aluminum powders were polycrystalline, and their shapes were very irregular. The size of particles was distributed at value between 0.5 and 10 μm. A mean particle size of the powder decreased with lowering atomization temperature and with increasing discharge of Ar gas and rotational speed of the disk. Nozzle diameter also influenced delicately on the distribution of particle size.View full abstractDownload PDF (710K) -
Tadao HIRANO, Tatsuo FUJITA1987 Volume 37 Issue 10 Pages 670-676
Published: October 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSRapidly solidified (RS) powder metallurgy (P/M) Al-Si-X system alloys were investigated. The P/M alloys were based on a hypereutectic Al-Si system, to which transition elements (Fe, Ni, Mn) were added up to 10wt%as well as 3wt%Cu and 1wt%Mg in order to improve the strength at elevated and room temperature, respectively. An addition of a transition element caused an intermetallic compound to be formed. Extruded P/M alloys had fine and homogeneous structures, which are not obtainable from ingot metallurgy (I/M) alloys. The Al-Si P/M alloys were higher in tensile strength than I/M alloys of the same compositions. An addition of transition element improved strength and thermal stability at elevated temperature. Moreover, an addition of Si and SiC particles improved seizure and wear properties. The P/M alloys containing more than 20wt%Si and a transition element had a low thermal expansion coefficient comparable to that of Lo-Ex alloys.View full abstractDownload PDF (1946K) -
Tatsuo FUJITA, Fumio KIYOTA, Tadao HIRANO, Yo KOJIMA1987 Volume 37 Issue 10 Pages 677-682
Published: October 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSAl-Si-X composites containing dispersed Si particles were prepared by powder extrusion. Wear characteristics of the composites were investigated by a pin-drum type wear testing machine under the lubricated of compressor oil. The wear resistance of the composites is extremely higher than that of the base material because of its large Si particles. In the case of the Si-dispersed composites, wear resistance increases with increasing of the hardness (strength) of the composites.View full abstractDownload PDF (2081K) -
Toshimasa MOROOKA, Eiji YUASA1987 Volume 37 Issue 10 Pages 683-689
Published: October 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe mechanical alloying process is a method for producing alloys with controlled structure. In this paper, Al-Cr and Al-Cr-C alloys were prepared by mechanical alloying and powder hot extrusion, and their tensile strength, hardness and microstructure were investigated. The fine particles of oxides and carbides gave a high hardness and high tensile strength to the alloys prepared by mechanical alloying. These alloys kept high hardness after heating about 400°C. Tensile strength at high temperature of these alloys decreased linearly up to 400°C.View full abstractDownload PDF (1784K) -
Su-gun LIM, Makoto SUGAMATA, Junichi KANEKO1987 Volume 37 Issue 10 Pages 690-697
Published: October 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSImprovement of conventional 2024 aluminum alloy was experimentally studied by the addition of transition metals and by rapid solidification and powder metallurgical process. Alloying additions were l to 4wt%Fe, 2 to 6wt%Mn and 2 to 6wt%Ni. Rapidly solidified flakes were produced by atomizing the alloy melt and subsequent splat quenching onto a water-cooled copper roll. Consolidation of flakes was done by cold pressing, degassing and hot extrusion. Microhardness of flakes increased with the addition of transition metals due to fine particles of their eutectic compounds. P/M materials from these flakes also contained fine dispersion of eutectic compounds and showed higher hardness even after annealed at high temperatures. Among these P/M materials, Mn bearing material showed the highest strength and Ni bearing one the lowest. However, addition of these elements appreciably reduced the age hardening of 2024 alloy. The alloys with large addition of transition metals showed appreciably higher fatigue strength than conventional 2024 alloy in high cycle fatigue.View full abstractDownload PDF (1895K) -
Kazuhisa SHIBUE, Hideo SANO, Shigenori YAMAUCHI1987 Volume 37 Issue 10 Pages 698-703
Published: October 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe relationship between structure and mechanical properties of extruded Al-210%Fe powder metallurgy (P/M) alloys was investigated. The yield strength (σ0.2) is related to the volume fraction of dispersoids (Vf) and the average dispersoid radius(r): σ0.2∝Vf3/2•r-1. This relationship suggests that higher Vf and smaller r result in higher strength. Increase of Fe content raises the strength of Al-Fe alloy because of the increase of volume fraction of dispersoids. Annealing at the temperature above 400°C lowers the strength of Al-8%Fe alloy because of coarsening of dispersoids.View full abstractDownload PDF (1518K) -
Shigenori YAMAUCHI, Kazuhisa SHIBUE, Hideo SANO, Kiyofumi ITO, Susumu ...1987 Volume 37 Issue 10 Pages 704-709
Published: October 30, 1987
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSIn this paper Al-Fe system alloys were mainly investigated from the viewpoints of solid solubility, diffusion coefficient, temperature of liquidus and material cost. The mechanical properties at the room and elevated temperature were evaluated in the various Al-Fe system alloys. Al-8%Fe-2%V-2%Mo-1%Zr alloy was found to be superior to the conventional 2618 alloy in the room and elevated temperature-tensile strength, in the thermal stability of hardness, and in the fatigue and creep properties. The excellent properties mentioned above were due to the existense of Al-Fe-V-Mo, Al-Fe and Al-Zr system dispersoids.View full abstractDownload PDF (1223K)
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