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Volume 26, Issue 2
Displaying 1-7 of 7 articles from this issue
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Shigeo MUROMACHI1976 Volume 26 Issue 2 Pages 65-66
Published: February 28, 1976
Released on J-STAGE: July 23, 2008
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Tetsuo WATANABE, Yen C HUANG, Ryuzo KOMATSU1976 Volume 26 Issue 2 Pages 67-75
Published: February 28, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSSeveral methods for determining the hydrogen content in magnesium have been adopted so far. However, the results of earlier investigations show a poor agreement due to the difficulty of analysis resulting from the nature of magnesium itself. The main difficulty in this sort of work, arises from the high vapor pressure of magnesium at higher temperatures. Magnesium vapor causes contamination of a vessel and reabsorption of hydrogen evolved from a sample may occur.
Present investigation was carried out by three different methods in order to extract hydrogen from magnesium samples. They are vacuum fusion, vacuum evaporation, and vacuum extraction of a sample sealed in palladium tube or in thin iron foil. The determination of the amount of hydrogen evolved from the magnesium sample was carried out with an ordinary gas analyzer. Among those three methods, the method of vacuum extraction with a sample sealed in palladium tube showed the highest reliability in determining the hydrogen content in magnesium.
Magnesium produced by the Pidgeon process contains about 18 to 22 cc of hydrogen per 100 grams of magnesium.View full abstractDownload PDF (933K) -
Tetsuo WATANABE, Yen C HUANG, Ryuzo KOMATSU1976 Volume 26 Issue 2 Pages 76-81
Published: February 28, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe solubility of hydrogen in magnesium has been studied by using a modified Sievert's apparatus over a fairly wide temperature range from 200 to 750°C under the atmopheric pressure of hydrogen. Themodified Sievert's apparatus was constructed with the causion to eliminate the change in the volume of the measuring system due to the room temperature change during the experiment.
Causion was also paid to minimize the loss of hydrogen introduced into the system by using the reaction tube made of quartz; 8mm in thickness and 14mm in inside diameter. There is no hydrogen loss due to permeation during the experiment at temperatures up to 750°C.
A difficulty associated with the determination of the solubility of hydrogen in magnesium arises from the high vapor pressure of magnesium. This was solved by sealing a magnesium sample in a thin-walled tube of stainless steel into which hydrogen is permeable. In the present experiments, a stainless tube (0.15mm in thickness and 10mm in diameter, 65mm in length) was used, and it could contain about 8 grams of magnesium.
The solubility of hydrogen at a temperature, T, will be given by the following equations;
log S (solid) cc/100 gr Mg = -1.10 × 103/T + 2.69 + 0.5 log PH2
log S(liquid) cc/100 gr Mg = -1.36 × 103/T + 3.21 + 0.5 log PH2
The heat of solution for hydrogen in magnesium was obtained by plotting the solubility of hydrogen against 1/T as follows; 5 Kcal/g atom hydrogen to the solid phase and 6.2 Kcal/g atom hydrogen to the liquid phase.View full abstractDownload PDF (733K) -
Matsuo MIYAGAWA1976 Volume 26 Issue 2 Pages 82-87
Published: February 28, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSThe bulge formed at the bottom of aluminum drawn cups by axial compression in secondary forming operations such as nosing, tapering, closing, and flaring at the open ends of cups gives sometime unfavorable effects to the dimensional accuracy of the final products.
Drawn cups are compressed axially by means of two parallel rigid flat plates, and the axial load and the deformation feature of bulge formation are measured with advancing of compression stroke of the press ram. The axisymmetrical deflection of the bottom plate occurs primarily with gradual increase in compression. The radial displacement of bulge at the cup bottom increases rapidly after the critical ram stroke, and reaches the maximum at the ram stroke nearly corresponding to the maximum load.
The axisymmetrical buckling stresses of thin cylinders, the maximum and the critical stresses of drawn cups are obtained for various geometrical dimensions which are denoted by the diameter to thickness ratio. The critical load gives the limit of secondary forming operations so as to obtain the favorable formed parts.View full abstractDownload PDF (599K) -
Hiroaki HIRASAWA, Masashi ISOBE1976 Volume 26 Issue 2 Pages 88-95
Published: February 28, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSPrecipitation processes of Mn- and Cr- bearing phases in age-hardenable aluminum alloys, Al-Mg-Si and Al-Zn-Mg, were investigated by resistivity measurements and electron microscopy.
It was expected that preexisting precipitates of the age-hardening phase could act as nuclei for the precipitation of Mn- and Cr- bearing phases. In this work, it was found that the precipitation of Mn is accelerated drastically in the presence of Mg2Si precipitates and some substantial evidences which support this mechanism were presented.View full abstractDownload PDF (1778K) -
Motohiro KANNO, Mikio FUJII, Hisashi SUZUKI, Shigeharu SAKANO1976 Volume 26 Issue 2 Pages 96-101
Published: February 28, 1976
Released on J-STAGE: July 23, 2008
JOURNAL FREE ACCESSFollowing the previous report on the aging curves of Al-4wt%Cu-Sn alloys, those of Al-4wt%Cu-Cd alloys with Cd content up to 0.064%, were investigated in relation to aging temperatures (TA), aging times (tA) and Cd contents by electrical resistivity measurement. The specimens were solution-treated at 520°C for 2hr, quenched and subsequently aged mainly at temperatures ranging from 0 to 200°C.
The results obtained were as follows:
(1) The aging curves varied continuously with TA, tA and Cd contents, and the precipitation process of ternay alloys seemed to be different from that of Al-Cu binary alloy. These results were the same as those of Al-Cu-Sn alloys previously reported.
(2) As for the aging curves at low temperatures, for instance, from -13 to 25°C, the changes of the initial rate of aging with the aging temperature and Cd content were examined, leading to the result that they were hardly explained by the vacancy-trap model so far postulated.View full abstractDownload PDF (656K) -
Takeshi MURAKAMI, Tsuneo TAKAHASHI1976 Volume 26 Issue 2 Pages 102-107
Published: February 28, 1976
Released on J-STAGE: November 05, 2008
JOURNAL FREE ACCESSDownload PDF (902K)
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