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Volume 24, Issue 2
Displaying 1-7 of 7 articles from this issue
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Mitsugu MOTOMURA, Hiroyuki KIKUGAWA, Yuji MATSUURA, Shigeo OYA1974 Volume 24 Issue 2 Pages 53-59
Published: February 28, 1974
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe pressure distribution along the arc of contact in cold rolling of aluminum sheets was measured by the pressure pick-up pin method. The samples were hot and cold rolled from soaked cast slabs with growth twins and columnar and equiaxed crystals. The initial orientation and the rolling texture affected the specific pressure in cold rolling and the texture dependence of the rolling pressure was able to be evaluated. The pressure distribution pattern was analogous to the friction hill whether the slab consisted of growth twins, columnar crystals or equiaxed crystals. The rolling textures, {112} <111>, {123} <121>, {113} <211> {236} <533> and {135} <522>, which were called high potential rolling textures, produced the large specific pressure along the contact arc. The rolling textures, {110} <112>, {110} <113> and {110} <335>, which were called low potential rolling textures, produced the small specific pressure. Sheets with the mixture of the high and low potential rolling textures were rolled with the medium specific pressure.View full abstractDownload PDF (873K) -
Shoji GOTO, Shigeyasu KODA1974 Volume 24 Issue 2 Pages 60-70
Published: February 28, 1974
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDuctility of aluminum alloy was studied in correlation with the fracture surface structure observed by electron microfractography. The results obtained are as follows:
In 1100 and 3003 alloys, the fracture surface was characterized by deep and large dimples, nucleated at lump shaped inclusions. However, about 10% of inclusions were associated with the dimple nucleation. The dimple density was correlated with the number of large inclusions rather than with the density of whole inclusions. The brittleness in the cold worked state was due to dimple initiation occurred easily.
In an Al-4%Cu alloy, the most ductile state was produced by the G. P. zone formation; very large dimples were observed on the fracture surface. G. P. zones were, thus, considered to contribute to hardening of the matrix but not to the dimple nucleat on, while inclusion particles initiated the dimples. The ductility was the lowest when the Θ' precipitation occured; very fine dimples were present on the fracture surface. A large number of weak Θ' precipitates acted as the dimple nuclei. Very fine dimples, nucleated at Θ particles, were observed at the over aged state. The small number of large precipitates resulted in the recovery of ductility.View full abstractDownload PDF (3250K) -
Yoshio BABA, Junji HAMADA1974 Volume 24 Issue 2 Pages 71-76
Published: February 28, 1974
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSEffects of TiB2 and TiAl3 particles, smaller than 15μ and 600μ, respectively, on grain refining of cast structure of 99.75% and 99.99% aluminum were studied. The results obtained are as follows:
1) Grain size of cast aluminum decreased when 0.01 to 0.10%TiB2 was added. This effect became more pronounced as the particle size decreased. Further, it was found that the refinement effect due to TiB2 was more effective when the temperature of molten aluminum was raised to 900°C and 0.006%Ti was added in advance.
2) Similarly, grain refining effect due to TiAl3 became more pronounced as the content of TiAl3 increased from 0.07% to 0.54% and the particle diameter decreased. This effect was further noted when the holding time and the temperature of the molten metal containing TiAl3 particles increased.
3) When 0.05%TiB2 and 0.016%TiAl3 were added together to the molten metals, the refinement effect was very pronounced if the particle sizes of TiB2 and of TiAl3 were less than 2μ and 100μ, respectively. This observation was consistent with the refinement effect of the Al-5%Ti-1%B master alloy on the cast structure of pure aluminum.View full abstractDownload PDF (1086K) -
Katsusuke NAGAHAMA, Isao MIKI1974 Volume 24 Issue 2 Pages 77-84
Published: February 28, 1974
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSRecrystallization and precipitation in an Al-0.5%Cr and an Al-0.5%Cr-0.05%Si alloy, solution treated at 640°C and cold rolled, then aged at various temperatures, were studied by measuring electrical resistivity and hardness and by conducting transmission electron microscopic observation. The results obtained are as follows:
1) Precipitation was acceleratec by cold work. This acceleration was marked in low temperature aging (>400°C), where recrystallization proceeded gradually.
2) Nucleation of the precipitates occurred preferentially at lattice defects, such as dislocations or subboundaries.
3) The acceleration of the precipitaion was attributed to easy nucleation at lattice defects. In low temperature aging, the precipitation rate was further incresed by the enhancement of solute diffusion during the gradual progress of recrystallization.
4) The precipitates were globular in form in low temperature aging and plates or needles in high temperature aging. The retardation of recrystallization by precipitation was observed.
5) The addition of a small amount of Si also enhanced the precipitation and retarded the recrystallization. The retardation of recrystallization was related to the enhancement of the precipitation.
6) Precipitate phases at all temepratures were the equilibrium Al7Cr phase.View full abstractDownload PDF (1447K) -
Kazuo TSUMURAYA, Tohru HASEGAWA, Yasuo OHNO1974 Volume 24 Issue 2 Pages 85-88
Published: February 28, 1974
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe effect of direct and alternating currents on the aging behavior of an Al-2.5%Cu alloy was investigated by electrical resistivity measurements. The aging rate increased with an increase of direct current density when it was in the range of 500 to 2000A/cm2. An alternating current of 50Hz also increased aging rate, in disagreement of the study by T. J. Koppenal and C. R. Simcoe. Acceleration of the aging by the application of electric current was explained on the basis of a temperature rise through Joule heating.View full abstractDownload PDF (454K) -
Seiki NISHI, Yoshie SHINADA, Tatsushi KUROBUCHI1974 Volume 24 Issue 2 Pages 89-99
Published: February 28, 1974
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (1441K) -
1974 Volume 24 Issue 2 Pages iiia
Published: 1974
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (72K)
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