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Volume 41, Issue 11
Displaying 1-11 of 11 articles from this issue
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Mitsuaki FURUI, Keiji MATSUEDA, Yo KOJIMA, Mamoru MATSUO1991 Volume 41 Issue 11 Pages 733-739
Published: November 30, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSScreen effect in Electromagnetic Casting (EMC) was continuously controlled over a wide range by replacing usually used metal screen with screen coil. The resistance of external coil with an insertable iron core was connected with condenser resonance circuit to obtain stronger electromagnetic fields. As a result, a maximum density of 0.13 T was obtained by this electromagnetic coil. By using this apparatus, the vertical side of levitated liquid metal is made more straight and the stable, vibrationless free meniscus is obtained. The area of horizontal cross section in the melt is also changed by altering the resistance of external coil, being influenced by number of turns and/or length of iron core insertion. This apparatus will contribute to the development of EMC.View full abstractDownload PDF (763K) -
Tadashi AIURA, Kazuhiko ASANO1991 Volume 41 Issue 11 Pages 740-745
Published: November 30, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSOn precision turning surface, intermetallic compounds become causes of cutting defects on surface of aluminum alloys. There are four kinds of diamond turning (D.T) defects: picking-off, crack, falling-off, and scratch. The largest one is scratch. This mechanism is considered in this study. It is found that scratches are affected by cutting feed and corner radius. It is considered with final depth of cut. It will be called critical depth of cut (Dcr). When this depth of cut is small, chips doesn't come out and the cut surface is vanished by frank. In this condition any scratches do not appear on cut surface. Vanishing phenomena of cut surface. This vanishing depends on the depth of cut at finish cutting. Dcr is calculated with tool feed and corner radius. Vanished thickness is found to be influenced by sharpness of cutting edge. It is proposed that scratching behavior is almost same with that of the built-up edge.View full abstractDownload PDF (914K) -
Osami SERI, Mitsunori IMAIZUMI1991 Volume 41 Issue 11 Pages 746-751
Published: November 30, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDissolution behavior of Al-Fe alloy in 1, 3 and 5% NaOH solution at room temperature (about 25°C) has been investigated. Weight loss of the Al-Fe alloy etched by the NaOH solution linearly increases with increase in concentration of NaOH. The dissolution behavior has been qualitatively interpretated in terms of superimposement of anodic polarization curve of pure aluminum and cathodic polarization curve of intermetallic compound. The intermetallic compounds which are electrically conducted to the aluminum matrix play a cathodic role, and at the same time they dissolve themselves into the solution due to their small polarization resistance.View full abstractDownload PDF (752K) -
Susumu IKENO, Kazuhiro KAWASHIMA, Kenji MATSUDA, Hiroshi ANADA, Shizuo ...1991 Volume 41 Issue 11 Pages 752-758
Published: November 30, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSAging behaviour of Al2O3-particle-dispersed (20vol%) Al-3.96%Cu and Al-4.09%Cu-1.58%Mg alloy composite materials was investigated by means of microvickers hardness, electrical resistivity measurements and transmission electron microscopy. In a case of an Al2O3/Al-3.96%Cu composite materials θ' phase precipitates on subgrain boundaries at an early stage of aging at 423K. After a prolonged agings an increased number of θ' precipitates are seen inside grains. While GP zones form normally in an Al-3.96%Cu alloy at this aging condition, no GP zones precipitate in the Al2O3/Al-3.96%Cu composite material and age-hardening does not take place. On the contrary, age-hardening is clearly observed in an Al2O3/Al-4.09%Cu-1.58%Mg composite material aged at 423K. In this composite material, both GP zones and θ' precipitates are found inside grains, being different from GPB zones and S' intermediate phases normally formed in an Al-4.09%Cu-1.58%Mg alloy.View full abstractDownload PDF (1920K) -
Naritoshi AOYAGI, Shoichi TAKAHASHI, Yo KOJIMA1991 Volume 41 Issue 11 Pages 759-765
Published: November 30, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDie casting of SiC whisker/ADC12 aluminum alloy composites was examined. The microstructure of composites added 0.9mass% magnesium or titanium in the matrix revealed the magnesium segregation at the boundary between the whisker agglomeration and matrix area, and the precipitates were observed in the composites by added 0.9mass% titanium. The interface between SiC whisker and matrix in the composites produced by die casting was observed well bonding except the void occuring for die casting process with TEM.
The tensile strength of composites was not always increased by whisker addition, the value was approximately the same value as strength of the ADC12, 260MPa. But proof stress of Mg containing SiC whisker composite increased in proportion to whisker volume fraction, e.g., the 0.2% proof stress increased up to 280MPa, and elastic modulus increased up to 82GPa, and the elongation reduced less than 1% by 10Vf% SiC whisker addition. The properties of whisker/ADC12-0.9mass% Ti matrix composites were similar to Mg containing composites. The remelting treatment of composites were improved the U.T.S, 0.2%P.S. and elongation. The whisker average length in composites produced with this production method was more than 10μm in all specimen.View full abstractDownload PDF (2443K) -
Kazuo KITAGAWA, Shuichi HIRATA1991 Volume 41 Issue 11 Pages 766-771
Published: November 30, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe effect of second phase on the rolling texture of Al-Al3Ni eutectic alloy has been studied. The shape of second phase was controlled to be fine particles or unidirectionally oriented fine fibers. It was found that the presence of second phase constricted the development of rolling texture of the material. The material containing fine particles showed a weak Cu type rolling texture. In the material containing fine fibers, however, texture development depended strongly on the rolling direction. Texture was very weak in the materials rolled parallel to fibers. TEM microstructure indicated that second phase impeded the formation of deformation bands and consequently caused the formation of subgrains. The DSC measurements revealed that the rolled material with weak texture had high stored energy.View full abstractDownload PDF (1434K) -
Mitsuo NIINOMI, Toshiro KOBAYASHI, Shinji HAKATA1991 Volume 41 Issue 11 Pages 772-777
Published: November 30, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe relationship between mechanical properties and microstructure, and the mechanism of strengthening of Al-18 wt%Si and Al-8wt%Fe alloys made by powder metallurgy process were investigate. Si particles are observed in the Al-18wt%Si alloys, and Al3Fe and Al6Fe particles are observed as intermetallic compounds in the Al-8wt%Fe alloys using an transmission electron microscopy. Work hardening mechanism of the alloys is summarized as follows: Firstly dislocation loops are formed around fine dispersion particles. Then, many dislocation such as like prismatic loops pile up as deformation progresses. Finally, stress concentration induced by dislocation loops is subjected to the plastic release. The strength of those alloys are related closely to both the volume fraction of particles and the particle size.View full abstractDownload PDF (1227K) -
Hideo USHIO, Tadayoshi HAYASHI1991 Volume 41 Issue 11 Pages 778-786
Published: November 30, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (2376K) -
Katsuzi TAKEUCHI1991 Volume 41 Issue 11 Pages 787-806
Published: November 30, 1991
Released on J-STAGE: October 30, 2008
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Katsuaki SUGANUMA1991 Volume 41 Issue 11 Pages 807-808
Published: November 30, 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (276K) -
1991 Volume 41 Issue 11 Pages vib
Published: 1991
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (117K)
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