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Volume 26, Issue 12
Displaying 1-7 of 7 articles from this issue
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Shiro YAMADA1976 Volume 26 Issue 12 Pages 585-586
Published: December 30, 1976
Released on J-STAGE: July 23, 2008
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Tsuneo TAKAHASHI, Yo KOJIMA, Yoshito OKI, Kazuhiro MIHAMA, Yoshinori A ...1976 Volume 26 Issue 12 Pages 587-593
Published: December 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe aging behaviors of Al-2%Cu binary and Al-2%Cu alloys containing 0.01, 0.02, and 0.03%Sn were investigated. Measurements of hardness and electric resistivity, X-ray diffraction and transmission electron microscopy were carried out. The clusters or aggregations of Cu atoms had been formed in the quenched state. The formation of clusters was suppressed with Sn addition. The clusters in the quenched state vanished partly during subsequent aging treatment. In the high resolution electron micrographs, the disc-like G. P. zones and θ"-phases were observed in the ternary alloys within short aging time in comparison with the binary alloys. The effect of Sn addition was shown as the growth of large precipitates with low density in comparison with the binary alloys.View full abstractDownload PDF (1256K) -
Yo KOJIMA, Tsuneo TAKAHASHI, Kazuhiro MIHAMA, Yoshinori ANDO1976 Volume 26 Issue 12 Pages 594-599
Published: December 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSHigh resolution electron microscopy including a lattice image technique was made on G. P. zones and θ"-phases in Al-2%Cu and Al-2%Cu-0.03%Sn alloys. Formation of G. P. zones and θ"-phases was accelerated by Sn addition to Al-2%Cu alloys. The size distribution of precipitates was different between Sn free and Sn containing alloys. In the size distribution histograms, the binary alloys had one peak, but the alloys containing Sn had separated two peaks. The precipitates in the binary alloys were not grown in size during aging process. However, those in the alloys containing Sn were linearly grown with aging time. The density of precipitates in both alloys were decreased with aging time. Particularly, in the alloys containing Sn, the competitive growth of precipitates probably occured with aging time in long-term aging.View full abstractDownload PDF (1938K) -
Hisashi SUZUKI, Motohiro KANNO, Shigeharu SAKANO1976 Volume 26 Issue 12 Pages 600-605
Published: December 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSWhether the G. P. zones change into intermediate phases (θ') was investigated by using a high resolution transmission electron microscope. Specimens were solution-treated at 520°C, quenched and subsequently aged at temperatures from 150 to 175°C for the time up to 104min. Either G. P. (2) zones in the binary alloy or G. P. (x2) zones in the ternary alloy corresponding to the above G. P. (2) zones were considered to transform continuously into θ' phases. Transformation in the ternary alloy was further accelerated than that in the binary alloy. In other words, in the ternary alloy, the aging time for the transformation was much shorter, and the dimension of G. P. (x2) zones when the transformation began to start was much smaller. At the edges of G. P.(x2) zones in the ternary alloy there precipitated Sn rich phases, being considered to play an important role for accelerating the transformation. The mechanism of G. P. zone→θ' transformation should be different in the binary and ternary alloys.View full abstractDownload PDF (1442K) -
Hisashi SUZUKI, Motohiro KANNO, Ichiro ARAKI1976 Volume 26 Issue 12 Pages 606-610
Published: December 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSEffects of such heat-treatment conditions as quenching into iced water (W. Q.), quenching into oil bath held at 200°C (D. Q.), and pre-aging at 100° and 140°C for specified time after these quenching treatment on the hardness of the alloy were investigated in relation to aged structures by means of transmission electron microscopy. The alloy aged at 200°C had the hardness remarkably increased under the condition of D. Q. than that of W. Q. This is considered to be due to the fact that the amount of intermediate phases (S') precipitating on dislocation loops decreases under D. Q. condition, accompanied with the increase in the amount of G. P. B zones. Pre-aging treatments were not so effective for the peak hardness after final aging at 200°C regardless of quenching conditions. This will be closely related to the strong tendency of S' in this alloy to precipitate on the loops. These facts are not entirely in accordance with previous informations. Further studies are required to be made in this respect.View full abstractDownload PDF (1143K) -
Yoshimitsu MIYAGI1976 Volume 26 Issue 12 Pages 611-614
Published: December 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSEffects of applied stress σ(kg/mm2) and test temperature T (°K) on stress corrosion life time (min) in ST-direction of Al-Zn-Mg alloy thick plate were investigated in a mixed chromic acid solution.
T being constant, linear relation existed between logσ and logt, and σ being constant, linear relation existed also between logt and 1/T. Effects of σ and T on t were srepresented by the equation, 1/t = K σ-1/n exp (-ΔH/RT) Herein, K, n, ΔH and R are constants, and R is gas constant 1.98 cal mol-1 deg-1, K is 5.5×103, n is 0.508 and ΔH is activation constant 12, 800 cal mol-1. It is considered to be more reasonable that applied stress σ should be replaced by σN, perpendicular component of applied stress to grain boundary.View full abstractDownload PDF (400K) -
Toshiro FUKUSHIMA, Toshio SUZUKI1976 Volume 26 Issue 12 Pages 615-625
Published: December 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (1582K)
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