All issues
Volume 44, Issue 8
Displaying 1-10 of 10 articles from this issue
- |<
- <
- 1
- >
- >|
-
Gaohui WU, Norio KOUNO, Tuneo TAKAHASI, Hisahuji WATANABE1994 Volume 44 Issue 8 Pages 421-426
Published: August 30, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe fabrication process named as pulse squeeze exhaust casting was developed. In comparison with the squeeze exhaust casting the process was characterized by controlling the press applied the molten metal in the manner of pulse, so that the air in the preform was fully exhausted. By this process the 6061 aluminum alloy composites containing Al2O3 particles of 0.15μm diameter have been successfully fabricated. The tensile strengths of samples with 30 vol% Al2O3 particles were 500MPa in the as-cast and 637MPa in the extruded conditions, and the elongation of extruded one were 8% at room temperature and 32% at 200°C, respectively.View full abstractDownload PDF (1404K) -
Tetsuichi MOTEGI, Eiichiro SATO, Kazuo OBATA1994 Volume 44 Issue 8 Pages 427-432
Published: August 30, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSIn order to understand the mechanisms of grain refinement of a superheat-treated magnesium alloy, pure magnesium samples containing 0 to 10at%Al were heated at 900°C and held for 1800s. The samples were then cooled at a constant rate and cast into a metallic mold at 660 or 680°C. Samples were melted ln the graphite, cast iron, and magnesla crucibles to clarify the influences of impurity elements in the crucible on the grain size. Metallographic examinations were performed to measure the grain size of solidified structures. An electron probe micro analyzer was used to find the foreign particles for heterogeneous nucleation in the fine grains. The grain refinement of superheat-treated Mg-Al alloys depends on aluminum content. The finest grain size was obtained in the Mg-6at%Al alloy. The grain size became coarser as the aluminum content increased or decreased from 6%. The molten magnesium alloy attacked the iron and magnesia crucibles, so Fe and Si contents of samples increased. However, no foreign particles such as metallic compounds which occur in heterogeneous nucleation were observed in any grain.View full abstractDownload PDF (3190K) -
Minobu SUKIMOTO, Naoyuki KOGA, Tatsuichi FUKUSAKO1994 Volume 44 Issue 8 Pages 433-438
Published: August 30, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSIn the development of flange made by an aluminum alloy casting for an air intake manifold (AIM) of a car, Al-Zn-Mg, Al-Mn-Mg, Al-Mg and Al-Mg-Si alloys were investigated on their casting properties, strength and brazability with A6063 alloy extrusion tubes. The alloy for the flange was required to have a solidus temperature higher than that of A4045 alloy and to have Mg content less than 0.6 mass%. Consequently, 712.0 alloy, which was inferior to Al-6Si alloy in casting properties but strong enough after the exposure to the brazing temperature, was chosen as the most suitable alloy for the flange. The casting design without defects was also studied using this alloy. Based on the fact that shrinkages were located in the part where G/√R_??_0.5 (G: the gradient of temperature, R: the cooling rate), the production of the casting flange without defects has been achieved by a high and long neck in the riser of the sand mold.View full abstractDownload PDF (898K) -
Shin-ya KOMATSU, Masahiko IKEDA, Yoshiaki TABATA, Takehisa GODA1994 Volume 44 Issue 8 Pages 439-444
Published: August 30, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe increase in resistivity with cold rolling up to 92% was measured for Al-Mg solid solutions having different Mg content. Starting from 1.7Ms or 34Ms holding at room temperature (RT) after 92% cold rolling, the decrease in resistivity by long period holding at RT and isochronal annealing up to 673K was also measured. Even for same reduction in thickness, as the Mg content becomes higher, the more lattice defects are introduced and then, the decrease in resistivity by annealing becomes larger with increasing Mg content. This is confirmed by the dependence of work hardening on the Mg content. Namely, the difference of the 0.2% proof stress between the cold rolled state and the annealed state is roughly proportional to the square root of the Mg content, and the resistivity increase due to dislocation density increased by cold rolling is proportional to the square of amount of work hardening.View full abstractDownload PDF (1293K) -
Isao KUBOKI, Yoshinobu MOTOHASHI, Mitsuji HIROHASHI1994 Volume 44 Issue 8 Pages 445-450
Published: August 30, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSTensile and hardness tests have been at room temperature carried out of superplastically deformed Ti-15V-3Cr-3Sn-3Al alloys. Aging at 753K after superplastic deformation at 1023K, above the β-transus, yields faster hardening response and higher maximum hardness and tensile strength. The tensile strength as well as total elongation are increased by aging after solution treatment of the superplastically deformed specimens, i. e., the strength vs. elongation balance of the alloys is improved by the deformation and solution treatment and aging thereafter. This improvement might be mainly caused by the precipitation of fine and acicular α-phases nucleated in thermally stabilized subgrains.View full abstractDownload PDF (1591K) -
Takeo OKI, Masazumi OKIDO, Hitoshi YOKOTA1994 Volume 44 Issue 8 Pages 451-455
Published: August 30, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe wettability between solid aluminum and molten tin, zinc and tin-zinc alloy was evaluated by means of an interfacial impedance method. The impedance response between two aluminum plates dipped into the molten metal was measured by a frequency response analyzer. The effects of surface roughness and oxidation of aluminum on the wettability were evaluated by comparing to standard aluminum surface. The equivalent circuit at the interface between the aluminum plates and melts was considered as the parallel connection of resistance and capacitance. The contact angle of metal on aluminum was also measured in vacuum and Ar atmosphere to compare with the impedance method. A small contact angle corresponds to the large capacitance of the equivalent circuit. The large value of capacitance is observed in the cases of higher temperature, the thinner oxide-layer on the aluminum-surface and smoother aluminum-surface. The impedance method, which shows the lower transition temperature for wettability than the sessile drop method, is found to be suited to observe wettability phenomenon. The value of capacitance after achieving a good wettability reaches about 4Fm-2 in any case of melts.View full abstractDownload PDF (586K) -
Kazuto YACHI, Nobuyuki MATSUBAYASHI1994 Volume 44 Issue 8 Pages 456-460
Published: August 30, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (1641K) -
Ryotatsu Otsuka1994 Volume 44 Issue 8 Pages 461-471
Published: August 30, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (2006K) -
Eizo IKEDA1994 Volume 44 Issue 8 Pages 472-473
Published: August 30, 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (283K) -
1994 Volume 44 Issue 8 Pages vb
Published: 1994
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (96K)
- |<
- <
- 1
- >
- >|