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Volume 26, Issue 11
Displaying 1-7 of 7 articles from this issue
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Yoshitsugu MISHIMA1976 Volume 26 Issue 11 Pages 537-538
Published: November 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (254K) -
Motohiro KANNO, Hisashi SUZUKI, Mikio FUJII1976 Volume 26 Issue 11 Pages 539-543
Published: November 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSA vacancy-trapping model has been proposed for explanation of the aging retardation in Al-Cu-Sn alloys at low temperatures in which Sn atoms would trap excess quenched-in vacancies causing reduction in diffusivity of Cu atoms. Although activation energies of initial aging experimentally obtained in binary and ternary alloys are of importance, little information concerns theoretical discussions on those energies. This paper theoretically discusses the activation energies assuming that the model is available. The activation energy is not peculiar to binary or ternary alloy and depends on the composition of the alloy and aging temperatures. If the energy of the alloy having a fixed composition is experimentally determined, only an apparent energy can be found as a function of two aging temperatures freely selected. The energy conventionally obtained by the least squares method using an experimental relation between ln R and 1/TA (R: initial rate of aging, TA; aging temperature) would not represent even the apparent one as mentioned above.View full abstractDownload PDF (649K) -
Takuichi MORINAGA, Shigeo ZAIMA, Tomohiro MINEGISHI, Nobutaka GOTO1976 Volume 26 Issue 11 Pages 544-549
Published: November 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe cutting behavior of Shirasu Balloon-Al-12%Si alloy composites has been studied and compared with that of silumin. The obtained results are as follows.
(1) As the joining force between Shirasu Balloons and the matrix in the composite is relatively low, cracking occurred ahead of the tool tip and Shirasu Balloons were dug out with the progression of cutting. It is therefore difficult to obtain good machined surface.
(2) The cutting resistance and the cutting temperature of the composite were considerably lower than those of silumin, and the built-up edge was not formed in cutting of the composite.
(3) In this experiment, the cutting resistance was lower and better machined surface was obtained in cutting with a high speed steel (SKH4) tool than with a carbide (K10) tool.
(4) Better machined surface was obtained for the composite of higher density which was made under higher casting pressure, although it showed slightly higher cutting resistance and higher cutting temperature.View full abstractDownload PDF (1434K) -
Hajime YAMADA, Takio TANAKA1976 Volume 26 Issue 11 Pages 550-557
Published: November 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe dendrite arm spacing, one of variable of cast structure, or cooling rate during solidification was applied as a criterion for machinability of various Al-Cu, Al-Si and Al-Mg casting alloys in turning tests. Refining the dendrite arm spacing leads to reduction in tool wear in accordance to the empirical equation VB = kDn, where D is dendrite arm spacing, VB flank wear of the tool, and k and n constants. Roughness of finished surfaces is remarkably increased with decreasing the cooling rate during solidification as a result of coarsening of secondary constituents. Decreasing the cooling rate remarkably increases the number of chips. The cutting force is independent of the cooling rate.View full abstractDownload PDF (1576K) -
Tetsuo UCHIYAMA, Yasuhiko SUZUKI, Shigeyasu KODA1976 Volume 26 Issue 11 Pages 558-563
Published: November 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSAn Al-Be eutectic alloy unidirectionally solidified had the colony structure in which beryllium fibers were aligned in the aluminum matrix. Orientation relationship between aluminum and beryllium was achieved by means of X-ray diffraction considering atomic matching of interfaces.
[001] Al // [0001] Be // growth direction
(100) Al // (2110) be // interface
(130) Al // (1230) Be // interface
(130) Al // (1320) Be // interface
The alignment of fibers near the colony boundaries was distorted. The tensile strength of a beryllium fiber 550kg/mm2 which corresponds to the theoretical strength of a beryllium whisker was calculated putting in a necessary correction.View full abstractDownload PDF (872K) -
Masao MIZUNO, Masao KIKUCHI, Yoshio BABA, Toshiyasu FUKUI1976 Volume 26 Issue 11 Pages 564-572
Published: November 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSA study was made on plate edges of bead-on-plate weld, three-pieces joint (deformed cruciform) fillet weld, and T-joint fillet weld in a commercial Al-Zn-Mg alloy. Structure of heat-affected zone was unsymmetric in both sides of weld bead closed to plate edge. The structure of plate edge was affected by distance from bead center to plate edge (L), plate thickness (T), temper of base metal, joint design and welding conditions. Re-solutioning of η' precipitates occurred in the plate edge by weld heat input, when plate edge was closed to weld bead. The difference of the structure in heat-affected zone between T6 and T7-treated plates was negligible. When plate edge was slightly aparted from weld bead (for instance L/T = 12 in thick plate, L/T = 23.5 in middle thick plate), various structural change such as partial re-solutioning of η' phase, reversion of G. P. zones, growth of η' phase or transformation to η phase occurred, which depended on L/T and temper, and resulted in a difference of the structure in heat-affected zone between T6 and T7-treated plates. The width of range of heataffected zone in T7-treated plate differed from that of T6-treated one.View full abstractDownload PDF (2616K) -
Nobuo URATA, Kunihiko MORI, Haruhiko IKEUCHI1976 Volume 26 Issue 11 Pages 573-583
Published: November 30, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSDownload PDF (1582K)
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