The effects of alloying elements on the solubility of hydrogen in magnesium were studied. The solubility of hydrogen was measured at 500°C for the solid phase and at 700°C for the liquid phase by using a modified Sievert's apparatns.
The solubility of hydrogen in magnesium is decreased by additions of Al, Ag, Cu, Mn, Pb, Sb, Sn and Zn, while it is increased by additions of Ni and Zr. The obtained values of the interaction parameter, e_H between each of alloying elements and hydrogen dissolved in solid and liquid magnesium are as follows;
element 500°C 700°C
Al 0.0018(<10.0%) 0.0074(<30.0%)
Ag 0.059(<1.0%) 0.026(<1.0%)
Cu - 0.040(<1.0%)
Mn 0.225(<0.20%) 0.093(<1.0%)
Pb O.046(<1.20%) 0.026(<1.0%)
Sb O.014(<0.84%) 0.008(<2.7%)
Sn 0.03(<1.5%) 0.012(<2.5%)
Zn 0.0043(<30.0%) 0.0091(<10.0%)
Ni -0.102(<9.0%) -0.0023(<48.5%)
Zr -0.365(<0.2%) 0(<0.5%)

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It has been reported that when metal is solidified from the flowing melt, the formation of the equiaxed grain structure is promoted. This investigation is concerned with the relation between the grain refinement and the flowing time under various amounts of superheat of the melt, in order to clarify the most effective time period of fluid flow.
Effective flowing time was between the cooling initiation and the dissipation of superheat of the melt. It was concluded that grain refinement was caused by dendrite arm segmentation at the growing interface and decrease in temperature gradient. After detachment of dendrites, it is necessary to inhibit the showering of bits by convection flow. It was shown that flowing motion of the liquid was effective in impeding the inverse segregation in Al-Cu alloy ingots.

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Studies were made on the effects of casting conditions, the float position and the mold design on the formation of feathery crystals in 6063 alloy DC ingots by using a laboratory casting machine.
The results obtained are as follows.
(1) The formation of the feathery crystals become easier with decreasing the distance from the float to the bottom of the mold.
(2) A mold with the thermal insulating material in the upper part of its cavity is very effective in making billets having complete feathery clystals.
(3) The formation of feathery crystals becomes easier with increasing the casting rate.
(4) The formation of the feathery crystals becomes easier with a rise of the casting temperature.

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Although the results of several investigations on the black spot formation on 6063 alloy extrusions have been reported, little information is available on the details of the effect of the surface treatment. The purpose of the present work is to make clear the factors controlling the formation of the black spot by the surface treatment and to confirm the origin of black coloring.
The black discoloration of the specimens became remarkable with increase of time and temperature of the desmutting treatment in sulfuric or nitric acid solution, and was found to be strongly, dependent upon the pH value of rinsing water after the desmutting procedure. It was concluded that the black spot formation by the surface treatment originated from the corrosion reaction between the β' Mg₂Si precipitates and the acid solution in the desmutting and subsequent water-rinsing treatment. The further observations showed that the aluminum interface at the black spot after anodizing was considerably rougher and fine particles were found in the anodic film which showed irregular cell structure.

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The bulging behavior of circular aluminum sheets was investgated by the electro-hydraulic discharge free-forming method, which was chosen as an example of high strain rate metal forming. Dynamical strains and strain rates were measured from the strain of punched pieces taken from a part of the polar circle at different polar deflections during forming. The stress-strain curves at the pole were obtained by measuring the working pressure from the movement of the piston which was interposed as a damper between the blank and explosive wire in order to uniform the pressure. The forming velocity was obtained by pin contacts in each forming condition.
The obtained results are as follows: (1) The relation between the polar deflection and the strain during forming was not very different from the relation obtained from each final polar deflection below the critical energy for failure. (2) The maximum strain rate reached to 2 × 10³ sec^-1 in O-temper sheet and 3 × 10³ sec^-1 in 1/2H sheet. (3) Above the critical energy, the strain rate reached to 8 × 10³ sec^-1 at failure in the polar circle. However, the forming velocity increased and the strain and strain rate with respect to the polar deflection decreased with an increase of the energy. It was found to fail in the die shoulder rather than in the polar circle, especially in 1/2H sheet. (4) In the stress-strain curves at the pole, the stress was higher in dynamical testing than in hydrostatical testing, especially in 1/2H sheet. (5) These tests of the forming behavior are thought to be applicable to other materials and forming conditons.

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