All issues
Volume 44, Issue 2
Displaying 1-11 of 11 articles from this issue
- |<
- <
- 1
- >
- >|
-
Tomoshi TAKAHASHI, Hidehiro YASUDA, Hideki ARAKI, Yoritoshi MINAMINO, ...1994 Volume 44 Issue 2 Pages 69-74
Published: February 28, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSInterdiffusion experiments of Al-rich α Al-Cu-Zn alloys have been performed at 817K. The concentration profiles indicate that the diffusion distance of Zn is somewhat longer than that of Cu in these solid solutions. The diffusion paths show S-shaped curves. The formation of S-shaped diffusion paths is attributed to the difference between the diffusion distance of Cu and Zn. The direct interdiffusion coefficients DAlZnZn, DAlCuCu are positive, and the indirect coefficients DAlZnCu, DAlCuZn are negative. The four interdiffusion coefficients are not sensitive to the solute concentrations. The magnitudes of DAlZnCu/DAlZnZn and DAlCuZn/DAlCuCu, indicate that Cu and Zn atoms in the Al-Cu-Zn alloys have attractive force between each other.View full abstractDownload PDF (645K) -
Shigeoki SAJI, Yibin ZHANG, Toshimi YAMANE, Junzo TAKAHASHI1994 Volume 44 Issue 2 Pages 75-80
Published: February 28, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSA method to estimate the enthalpy difference between a non-equilibrium state and the equilibrium state by means of the special DSC measurement was proposed and applied to melt-spun Al-(1.7-7)at%Mn and Al-(3.5-5) at%Mn-(0.8-2)at%Co alloys obtained by a single roll method. The enthalpy increment is due to both the retardation of phase transformations and the formation of refined microstructures during rapid solidification. The enthalpy increment due to the retardation of phase transformations increases with increasing amount of manganese and cobalt. The enthalpy increment due to manganese increment is larger than that due to cobalt increment, because the formation of the equilibrium phase Al9Co2 and Al6Mn is accelerated by addition of cobalt. The enthalpy increment due to the refined microstructure in melt-spun Al-Mn-Co ternary alloys is roughly 2-3 times larger than that in melt-spun Al-Mn binary alloys.View full abstractDownload PDF (1019K) -
Shu KURODA, Kazuaki OKUMURA, Tadakazu OHNISHI, Hiroyuki ICHINOSE, Nobu ...1994 Volume 44 Issue 2 Pages 81-85
Published: February 28, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe corrosion rate of 5083 aluminum alloy cold rolled by a constant reduction rate (10% per pass) or a constant reduction amount (10% of original thickness per pass) method was measured in a 0.5mol/l-NaOH solution at 40°C. The changes in corrosion rate with the total reduction correspond very well to the changes in residual stress of the samples. For the sheets rolled by the constant rate method, the corrosion rate and the residual stress show the maximum at about 50% total reduction. In the case of constant amount rolling, both show two maxima at 30% and 80%, and show a minimum at 50% total reduction. These tendencies can be understood from the fact that the deformation process, which has the characteristic of the development of shearing band in the case of 5083 alloy, differs in the two rolling methods.View full abstractDownload PDF (860K) -
Naobumi SAITO, Masaru NAKANISHI, Yoshinori NISHIDA1994 Volume 44 Issue 2 Pages 86-90
Published: February 28, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSEffect of heat treatment (solution treatment and aging treatment at 443K) on the tensile strength between room temperature and 773K was investigated of the aluminum-borate whisker reinforced (Vf=0.16 and 0.29) 6061 aluminum alloys. Tensile strength of the as-cast 0.29 Vf composite is in the measured temperature range about twice higher than that of the matrix alloy. No whiskers are observed on the fracture surfaces of the composites up to 573K. Both tensile strengths of the matrix alloy and of the 0.29 Vf composite are increased by aging treatment. The degree of the increase is, however, smaller for the composite than the matrix alloy. In the heat-treated composites, whiskers are observed on the fracture surfaces. This result shows that the strength of matrix alloy/whisker interface is decreased by the heat treatment.View full abstractDownload PDF (1201K) -
Tatsuya OHMI, Masayuki KUDOH, Kenichi OHSASA, Youichi ITOH, Kiyotaka M ...1994 Volume 44 Issue 2 Pages 91-96
Published: February 28, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe primary silicon crystals of hypereutectic Al-Si alloys are reported to be refined by the Duplex Casting process (a two-step casting of two molten alloys with different composition; i. e., "the first alloy" with lower liquidus temperature and "the second alloy" with higher liquidus temperature). Recently, concerning the refining mechanism, the authors have proposed that copious nucleation of primary silicon crystals takes place in the second alloy which is rapidly cooled and highly undercooled during mixing with the first alloy. The purpose of this study is to investigate the degree of under-cooling and the solidification behavior of the fluid clumps of the second alloy which are thought to form the clustering structures of fine primary crystals. The relationships between the degree of undercooling and the primary silicon size of Al-32 mass%Si and Al-22 mass%Si alloys were obtained by use of three solidification techniques: (1) air-cooling or immersion into a metal bath of melt-filled graphite crucible, (2) casting in a wedge-shaped copper mold, and (3) melt-in-jection into a lead bath. The primary silicon size of the finest cluster observed in the ingot produced by the Duplex Casting process with the combination of Al-12 mass%Si alloy and Al-32 mass%Si alloy is 15μm, and the corresponding undercooling is estimated at 243K.View full abstractDownload PDF (1165K) -
Hirofumi INOUE, Naotsugu INAKAZU1994 Volume 44 Issue 2 Pages 97-103
Published: February 28, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSTheoretical γ-values calculated from crystallite orientation distribution functions by using the Taylor theory have been compared with experimentally measured γ-values in annealed aluminum alloy sheets. The calculated and measured γ-values for a 6061 aluminum alloy consisting of the retained rolling texture and of the cube texture are relatively well consistent, but these values for a 5052 aluminum alloy consisting mainly of the cube texture are less consistent in the vicinity of a 45° direction. This is thought to be essentially due to the lack of validity of an analytical model for the 5052 alloy. Planar anisotropy of the γ-value, however, can be generally estimated by the present model. From the calculated results concerning some ideal orientations, it is found that a high γ-value may be obtained by developing the R-orientation as a main component and the Goss orientation as a secondary component.View full abstractDownload PDF (918K) -
Fumihiro SATO, Yoshihiko ASAKAWA1994 Volume 44 Issue 2 Pages 104-109
Published: February 28, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSCorrosion behavior of diecast magnesium alloy AZ91D-F anodized in Al2(SO4)3 added solution (Dow17) has been investigated by salt spraying test (SST). Both weight loss and estimated maximum corrosion depth decreased with increasing Al2(SO4)3 content and with increasing duration of SST. Corrosion area ratio, however, was independent of the amount of Al2(SO4)3. X-ray diffraction, EDX and ESCA analyses showed that the anodizing film consisted of Cr2 O3, MgF2 and NaMgF3, and that silicon oxide deposited on the anodized film by sealing treatment, in which not only chemical composition of the film but also the deposition behavior of silicon oxide depended on the amount of Al2(SO4)3. The addition of Al2(SO4)3 decreased the coupling current between anodized specimen and mechanically polished one, down to about one tenth of the initial value.View full abstractDownload PDF (1079K) -
Katsuhiro IMAZU1994 Volume 44 Issue 2 Pages 110-115
Published: February 28, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (1056K) -
Shigeru NAGASAWA1994 Volume 44 Issue 2 Pages 116-125
Published: February 28, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (1309K) -
Hideo YOSHIDA1994 Volume 44 Issue 2 Pages 126-127
Published: February 28, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (269K) -
Naritoshi AOYAGI1994 Volume 44 Issue 2 Pages 128
Published: February 28, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (124K)
- |<
- <
- 1
- >
- >|