Effect of red phosphor addition to Al-Si, Sn-Si and Ag-Si alloys was studied with metallographic examination and line analyses on an X-ray microanalyses.
Microstructures and line analysis charts of Al-25%Si alloys with 0.1%P and pure aluminum with 1.0%P are shown in photos 1 through 2 and those of Sn-6%Si and Ag-8%Si alloys with 2%P and 3%Al are shown in Photos 4 and 5. The results obtained are as follows:
(1) When phosphor is added to molten Al or Al-Si alloys, a compound, commonly identified with AlP, is formed. When phosphor and aluminum are added together to molten Sn-Si or Ag-Si alloys, a compound, identified with AlP, is also formed.
(2) With addition of P or P and Al together, grains of primary silicon in hyper eutectic Al-Si, Sn-Si and Ag-Si alloys are refined.
(3) Most Al-P phases are included in refined primary silicon crystals. However, some AlP particles are also present in the matrix which is free from primary and eutectic silicon crystals.
(4) When a metal mold is used, grain sizes of primary silicon and of AlP particles in silicon crystals as well as particle sizes of specimens, as a whole, became smaller than when a sand mold is used. The above experimental results seem to support the "foreign nucleus theory" which has been proposed to account for refinement effect of phosphor.

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The correlation between stress corrosion resistance and positions in extruded Al-Zn-Mg alloys with heavy rectangular section was experimentally studied and the relation between stress corrosion resistance and grain shape was discussed.
(1) Along the geometrical ST-direction, stress corrosion resistance was the lowest at the upper surface, decreased towards the center and was the highest at the side surface. On the other hand, along the geometrical LT-direction, the stress corrosion resistance was the highest at the upper surface, decreased towards the center and was the lowest at the side surface.
(2) In materials with elongated or flat grain shape, stress corrosion resistance was higher when stress was applied parallel to elongated or flat grains while it was lower when stress was applied perpendicularly to elongated or flat grains. However, when materials had equiaxed grains, the directionality of stress corrosion resistance was weak and stress corrosion resistance showed a medium value along any direction.
(3) When applied stress was constant, time to failure decreased as the anisotropy factor K increased and became constant when K exceeded about 4. The anisotoropy factor K was expressed as n₁/n₂, where n₁ was the average grain diameter in the perpendicular direction to the stress axis and n₂ was that in the parallel direction to the stress axis, respectively.
(4) When applied stress, σ, was constant, log{σK²/(1+K²)}, which was stress perpendicular to the grain boundary, was linearly related to logt, where t was time to failure. This suggests that grain shape dependence of stress corrosion resistance was equivalent to dependence of stress corrosion resistance on stress perpendicular to grain boundaries.

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Temperature dependence of dynamic elastic moduli of wrought aluminum alloys was studied by a resonant frequency method and the measured dynamic moduli were compared with the moduli determined by an ultrasonic method, reported in the previous paper. It was found that the elastic moduli weakly and linearly depended on the temperature below 250°C and that they decreased intensely with increasing temperatures above 250°C. Temperature dependence of the elastic moduli was nearly same for all the tested alloys within an experimental error. In terms of elastic moduli at room temperature, wrought aluminum alloys were classified into the following three groups: high strength alloys such as 2024-T4, 2024-0 and 2017-T4 with Young's modulus of (7.167.39)×10⁵kg/cm², such alloys as 2011 and 5052-0 with smaller Young's modulus of (6.546.17)×10⁵kg/cm² and such alloys as 2017-0, 5056-0 and 1100-0 with intermediate Young's modulus. A very close agreement between the modulus determined by a resonant method and that determined by an ultrasonic method was found for 2017-0, 2024-T4 and some other alloys. However, 2011-T3 and 2017-T4 alloys showed a difference between the moduli determined by the above two methods. This was considered due to the difference of measurement principles and of hypotheses or assumptions involved in calculations. This conclusion, therefore, suggests that elastic moduli should be reported with a clear indication of a measuring method.

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Solubility of beryllium in aluminum was determined by means of electric resistance measurement and microscopic examination. It was found that the solubility of beryllium in aluminum decreased repidly as temperature decreased; the solubility was 0.25wt.%at 630°C, 0.15wt.%at 600°C and less than 0.07wt.%at 560°C. The equilibrium diagram of the aluminum-silicon-beryllium was also investigated by thermal analyses, microscopic examination, and X-ray microanalyses. It was concluded that this system had a peritecto-eutectic reaction instead of a eutectic reaction which had previously been reported. The peritecto-eutectic reaction was expressed as Liquid+Be = Al+Si at 571°C. The composition at this reaction was 13wt.%Si, 0.5wt.%Be and the rest of Al. The primary surface for aluminum in the present system had a minimum position.

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The recovery and nucleation process of high purity cold rolled aluminum sheets was investigated by electron microscopic observation. The following results were obtained:
(1) It was confirmed that regions with cubic orientation existed in the cold rolled state.
(2) The region with the cubic orientation became a preferential nucleation site during heat treatment.
(3) Generally, the region with the cubic orientation could be derived by the rotation around the <III>_M axis from the matrix.
(4) However, there were six cases where the cubic orientation was described in terms of the 18.5° rotation around the <100>_M axis from the matrix.
(5) Regions with non-cubic orientation polygonized by heating, but rarely became recrystallization nuclei because they made low angle boundaries with the surrounding matrix.
(6) It was reasonable to consider that the recrystallization texture with the cubic orientation was formed by the process of the oriented nucleation and growth.

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