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Volume 26, Issue 9
Displaying 1-9 of 9 articles from this issue
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Kazuo UCHIYAMA1976 Volume 26 Issue 9 Pages 425-426
Published: September 30, 1976
Released on J-STAGE: July 23, 2008
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Hisashi SUZUKI, Motohiro KANNO, Ichiro ARAKI1976 Volume 26 Issue 9 Pages 427-431
Published: September 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe region (D (θ') region) where finer θ' precipitates were formed densely was found adjacent to the grain boundary in Al-(24)wt%Cu-Sn alloys, when solution-treated, quenched and aged at 200250°Ç. In this report, the formation of the D (θ') region in Al-Cu-Sn alloys was studied in relation to quenching conditions and solution-treatment temperatures (Ts) by using a transmission electron microscope. The results obtained are as follows.
(1) The D (θ') region was found to be caused by appearance of the region where Sn rich phases precipitated densely in the early stage of aging.
(2) The D (θ') region formed only under the condition of fast quenching (i. e. quenching into iced water). The width of D (θ') region and the distance from the grain boundary to D (θ') region increased with lowering Ts.
(3) These results would be explained from the following assumption: A transient peak of vacancy concentration profile developes adjacent to the grain boundary in the early stage of aging, owing to the formation of secondary defects inside the grain.View full abstractDownload PDF (1178K) -
Mitsugu MOTOMURA, Saburo SHIMAMURA, Takashi NISHIMURA1976 Volume 26 Issue 9 Pages 432-440
Published: September 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe resistance to deformation of commercial pure aluminum and aluminum alloys has been investigated experimentally by using a cam plastometer. Materials tested in this peper are A1070, A1050, A1100, A3003, A5052, Al-1.2%Cu (KD) alloy. The deformation resistance-strain curves of those materials have been determined over a temparature range 300500°Ç, strain rate 1.012.0 sec<-1>. The deformation resistance Kf was related to the true strain ε and the strain rate ε through a power law, i. e., Kf = Knεn and Kf = Kmεm. The relation between the deformation resistance Kf, temperature T, strain ε, strain rate ε can be expressed not by the usual form; Kf = K0εnεme<A/T> but by the form; Kf = (a+b/T+c/T2)εnεm, where a, b, c, n, m are constants dependent only on the material.View full abstractDownload PDF (1302K) -
Tadashi MOMONO, Katsuya IKAWA1976 Volume 26 Issue 9 Pages 441-450
Published: September 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSArtificial convection flow caused by Lorentz-interaction between a magnetic field and a direct current created wide equiaxed zones in aluminum alloy ingots. Mechanical properties were examined for these ingots by tensile and Charpy impact test. The results obtained were as follows.
In hypo-eutectic specimens, Al-Cu and Al-Si alloys solidified with artificial convection flow exhibited higher tensile strength and 0.2% proof stress than without convection flow, whereas lower elongation and reduction of area were obtained in the former case than the latter. It was postulated that the strength increased by the grain-refinement but the ductility decreased by micro-shrinkage cavities caused by violent convection flow.
In Al-CuAl2 and Al-Al3Ni eutectic alloys, the tensile specimens from the ingot solidified with no convection flow exhibited higher tensile strength than the specimen with artificial convection flow when loaded parallel to the growth direction. It was suggested that this behavior was due to the presence of lamellar or rod-type intermetallic compound with reinforcement in the former but the presence of degenerated structures caused by flowing melts in the latter.
In Al-Si eutectic alloys, the tensile properties were improved by artificial convection flow. It was correlated with uniform refinement of eutectic silicon phase in solidification with convection flow.
Charpy impact values of the hypo-eutectic specimens depended strongly on the direction and configuration of primary aluminum-rich dendrites. In the case of eutectic specimens, it was postulated that the continuous aluminum-rich matrix resulted in higher impact values when the impact direction was parallel to the direction of solidification.View full abstractDownload PDF (2687K) -
Masao KIKUCHI, Yoshihisa KITAGUCHI, Masao MIZUNO1976 Volume 26 Issue 9 Pages 451-455
Published: September 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSAging characteristics of an Al-6%Zn-2%Mg alloy cast into copper, iron and plaster molds were studied by means of hardness measurements, X-ray small angle scattering method and transmission electron microscopy. It was found that the initial aging rate was retarded and the age hardenability decreased in an Al-Zn-Mg cast alloy when rapidly solidified. The age hardenability in rapidly solidified Al-Zn-Mg alloy decreased as the cooling rate decreased. These results were discussed in terms of dislocations introduced during solidification and microsegregation of solute atoms.View full abstractDownload PDF (1576K) -
Ken TOHMA, Yo TAKEUCHI1976 Volume 26 Issue 9 Pages 456-462
Published: September 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSIn order to examine mechanical properties and recovery rate during deformation of Al-Fe, Al-Go and Al-Ni alloys, and to compare them with those of pure aluminum, room temperature tensile tests have been carried out.
These materials have high tensile ductility and exhibit steady state deformation at high strains. In this deformation range characteristic dislocation cell structures were observed on transmission electron microscopic examination, and the contribution of internal stress to applied stress was nearly 100%, so that deformation of these alloys are understood by the recovery controlled mechanism. Recovery rate depended strongly on strain rate, while no apparent difference in recovery rate was observed between the materials at a constant strain rate.View full abstractDownload PDF (1330K) -
Satoru NAKATSUGAWA1976 Volume 26 Issue 9 Pages 463-472
Published: September 30, 1976
Released on J-STAGE: July 23, 2008
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Yo KOJIMA, Tsuneo TAKAHASHI1976 Volume 26 Issue 9 Pages 473-491
Published: September 30, 1976
Released on J-STAGE: July 23, 2008
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1976 Volume 26 Issue 9 Pages 494
Published: 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (81K)
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