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Volume 40, Issue 8
Displaying 1-13 of 13 articles from this issue
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Katsuya IMAI, Shigeru YONETANI, Hisakimi NOTOYA1990 Volume 40 Issue 8 Pages 573-579
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSAl-Si alloy castings, AC3A, were dry ground at different depth of cut, work speed and wheel speed. Both the residual stress and residual shearing stress in the specimens were measured. Normal residual stress generated in the grinding direction was tension at the surface of the specimens. Tensile residual stress at the surface was small. The residual shearing stress at the surface decreased with the increase in the depth of cut and work speed. Textures at the grinding surface and slightly inner regions of the specimens were investigated. Textures at the grinding surface were similar to each other for all grinding conditions, while textures at the slightly inner region were different from those at the surface. The influence of the alloy structure on the residual stress was discussed.View full abstractDownload PDF (802K) -
Kenji MATSUDA, Yasuhiro UETANI, Shizuo TADA, Susumu IKENO1990 Volume 40 Issue 8 Pages 580-586
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSTensile test was performed in order to clarify a part of localized deformation at the grain boundary in the intergranular fracture of age-hardened Al-1%Mg2Si base alloys. The scratched marks on the surface were split into segments having gaps between them at the grain boundaries with increasing of deformation. The gaps had the maximum value at the mid point of grain boundary when the angle between the grain boundary and the tensile axis had 50-60 degrees deviation. This fact shows a possibility that an unusual deformation such as grain boundary sliding may be occured in this alloy. At some grain boundaries there were the steps that were formed by the vartical displacement between the neighboring grains at specimen surface. This phenomenon could not be interpreted by the conventional model of the grain boudary sliding.View full abstractDownload PDF (1462K) -
Minami KIMURA, Masaru KOBAYASHI1990 Volume 40 Issue 8 Pages 587-592
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSIn order to obtain a high frictional and good wear resistance surface, the superplastically embedding process of SiC powder into Zn-Al eutectoid alloy plates was developed. The embedding mechanism was investigated using the experimental simulation. The upper surface of a Zn-21.5%Al-0.5%Cu-0.01%Mg alloy (SPZ) specimen of the size 13×13×3mm was covered with SiC powder classified into +150, +250 and +355μm in size, with the density of 0.08-0.15mg•mm-2, and then forged superplastically at the punch speed of 1.7×10-3 to 1.7×10-1mm•s-1 at the temperature range of 473 to 523K. The embedding mechanism of SiC powder into SPZ specimen was analyzed using a glass-ceramics sphere of 6.0mm in diameter. The projection height and embedding efficiency depended on the applied stress ratio of SiC powder to the yield stress of SPZ.View full abstractDownload PDF (870K) -
Minami KIMURA, Masaru KOBAYASHI1990 Volume 40 Issue 8 Pages 593-598
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSIn order to reduce the assembling processes in manufacturing small, thin and precise parts, superplastic embossing method with the continuous supply of discs was newly developed. Using the Zn-21.5% Al-0.5% Cu-0.01%Mg alloy (SPZ) sheet, the stacked disc block of a disc specimen in thickness of 0.4 to 1.0mm, in the thickness/diameter ratio of 0.013 to 0.03 and two dummy discs in the thickness of 1.0mm were superplastically forged at 523K. A forged specimen and dummy discs were easily separated and these are discharged from the die after embossing. The configuration of embossed products was dependent on the superplastic forming conditions of temperature, punch speed and load. Under the optimum condition, highly accurate embossed-projection with sharp and lackless corner and without draft angle was obtained. Equivalent strain at the top corner of the projection was lager than 1.4. In the heavily deformed portion of the embossed discs with the equivalent strain of 1.0, the aspect ratio of grain changed from the initial value of 1.8 to 1.2 after superplastic embossing. The present method can be applied to form a precision part of watch dial.View full abstractDownload PDF (858K) -
Residual stress generated by cold-rolling and low-temperature absorbed energy in 5083 aluminum alloyYoshihiro NAKAYAMA, Tetsuya TAKAAI1990 Volume 40 Issue 8 Pages 599-605
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSRelationship between the residual stress generated by cold-rolling and the absorbed energy in Charpy impact test of LS type specimens of a 5083 aluminum alloy were investigated. The residual stress by cold-rolling of about 30% was measured using X-ray technique. Absorbed energy was obtained at 77K using an instrumented Charpy impact test equipment. The residual stress was accurately measured by assuming the plane stress condition for the specimen. The macroscopic residual stress was different depending on the chemical composition and microstructure of specimens. The microscopic residual stress estimated from the half-value breadth (FWHM) change showed good correlation with the micro Vickers hardness. The absorbed energy decreased with the decrease in the microscopic residual stress. Further investigation was required to understand the relation between the macroscopic residual stress and the fibrous structure formed by cold-rolling.View full abstractDownload PDF (951K) -
Takeshi SADAHIRO, Masaru YAGI, Hiroaki KURITA, Hisashi SUZUKI1990 Volume 40 Issue 8 Pages 606-611
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSSintered WC-W2C compacts were used as the substrate for diamond deposition, because the compacts were expected to be a carbon sink during CVD to improve the adhesion strength between diamond film and substrate. The adhesion strength has been found to be improved, as expected, with increasing W2C content in the range up to about 50%. The diamond deposited WC-(6-22)% W2C tools show the most excellent cutting performance for hyper-eutectic Al-20mass% Si alloy. The effects of W2C in the substrate are in detail discussed.View full abstractDownload PDF (2782K) -
Yoshimasa TAKAYAMA, Tatsumi TOZAWA, Hajime KATO, Hiroshi SHIRAI1990 Volume 40 Issue 8 Pages 612-618
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe distribution of three dimensional grain size has been directry measured during grain growth of pure aluminum by the special method of separating and weighing individual grains, which was used by Rhines and Patterson. It is concluded in consideration for the limit of measurabilitiy that the observed grain size distribution is approximately log normal for all specimens, and its spread does not vary remarkably during grain growth in this experiment. The grain size distribution from the computer simulation of grain growth by Exxon group is shown to be closer to the present experimental result than that from the representative theory of grain growth by Hillert, which is attributed to the fact that the former deals with growth or shrinkage of the individual grains while the latter growth of an isolated grain in an average environment.View full abstractDownload PDF (879K) -
Hajime KATO, Tatsumi TOZAWA, Yoshimasa TAKAYAMA1990 Volume 40 Issue 8 Pages 619-624
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSA bending-type fatigue testing apparatus designed for the fatigue test in vacuum was manufactured for the experiment. The alternate bending stress was applied to a specimen by electrodynamic conversion. Tests were performed in air (1.0×101Pa) and in vacuum of 5.3×10-3Pa atmosphere for the notched plates of an AZ31 magnesium alloy. The fatigue life in vacuum (Nf)V was longer than that in air (Nf)A. The ratio of (Nf)V/(Nf)A tended to increase with the decrease in the stress amplitude. The increment of fatigue life in vacuum was observed at both crack initiation and propagation stages.View full abstractDownload PDF (885K) -
Shinji TERUTA, Masafumi MIZOUCHI1990 Volume 40 Issue 8 Pages 625-632
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe strip-cast Al-Mn-Fe base alloys exhibit a superior heat resistance to the DC-cast ones because the amounts of Mn and Fe in solid solution are sufficient enough to affect the recrystallization of the strip-cast alloys. When the strip-cast alloys cold-rolled to higher reduction are annealed at a slow heating rate, such as in the box type furnace, 45° earing becomes dominant and the recrystallized grains grow coarsened. In this work, the effects of two types annealing furnaces, cold-rolling reduction before annealing, once or twice annealing and the Mg-addition on both the recrystallized grain size and cube texture were investigated in Al-Mn base alloys. The following results were obtained. In the stripcast Al-Mn base alloys, fine recrystallized grain size as well as the lower earing were produced by supersaturation of Mn, which were obtained by the high heating rate to the annealing temperature such as the salt-bath annealing simulated the CAL. The increased cold-rolling reduction before salt-bath annealing resulted in the fine recrystallized grain size and the decreased cube texture intensity. Twice intermediate annealing to get hardened materials were effective to obtain low earing materials. The increased Mg addition resulted in the fine recrystallized grain size. The alloys containing 0.3-0.5wt% Mg exhibited the highest 0-90° earing by the additional intermediate annealing.View full abstractDownload PDF (1500K) -
Isamu OKU, Masatomi INOKUMA, Kiyoshi AWAI1990 Volume 40 Issue 8 Pages 633-639
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (888K) -
Hirokazu SAKAKI1990 Volume 40 Issue 8 Pages 640-648
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
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Junichi KANEKO1990 Volume 40 Issue 8 Pages 649-650
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (326K) -
Michitomo KATO1990 Volume 40 Issue 8 Pages 651-652
Published: August 30, 1990
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (236K)
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