Al-4.5% Cu alloys containing Mg up to 4% were solidified under hydraulic pressure up to 3, 000kgf/cm². These castings have an outside columnar crystal zone and a segregation zone near the center. Occurances of these zones are reduced with increasing Mg content. Although the pressured castings have dendritic structures finer than gravity castings, the finess is independent of the applied pressure. The pressure effect on the cast structure is diminished by T6-treatment. Tensile strength and particularly elongation and impact value of the pressured castings are improved with increase of the applied pressure. The alloy containing 1% Mg has the maximum tensile strength regardless of the applied pressure. More of Mg results in lowering the elongation and impact value.

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The forming limit curves (FLC) of 1050-O and 1050-H14 aluminum sheets were determined. The effect of plastic properties of the sheet materials on the FLC was investigated. For determining the forming limits, a slight difference between two methods, the stretch-forming with cut blanks and the hydraulic bulging with an elliptical die was ob- served. The experimental FLCs were compared with the theoretically calculated curves. The FLC is markedly affected by the variation in n-value, however, not affected by the variation in r-value of the material.

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Fatigue tests under alternate bending stress in air and 3% NaCl aqueous solution were carried out for commercially pure aluminum plates containing various of Fe and Si. The ratio of the number of cycles to failure in the solution to that in air decreases as Fe and Si increase. The bending stress σ, tensile strength σ_B and number of cyles to failure N_f are expressed independently of Fe and Si contents as follows:
(σ/σ_B)^7.3N_f=10^3.6(in air), (σ/σ_B)^5.3N_f=10^3.6 (in 3% NaCl aq. sol.)
The macro-fracture changes gradually from a serrated type to a straight line type as Fe and Si increase. Pits formed at the end of the specimen of low Fe and Si contents spread parallel to the stress direction, but ones in the specimen of high Fe and Si contents advance perpendicular to the stress direction. Ductile type striations are found on the fracture of low Fe and Si aluminum both in air and the solution. Tangled striations are found on the fractographs of the specimens containing high concentrations of Fe and Si fatigued in air at low bending stress, and brittle fractures are found on those fatigued in the solution.

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Aluminum wires drawn up to 50.5, 71.8 and 93.0%in reduction of area were annealed at 340°C for 30min and secondarily drawn. Mechanical testing and determination of (111) pole figures were made. The first drawing texture of the wire drawn by 93% in reduction of area which is inferior in mechanical properties to the textures of the wires drawn by 50.5 and 71.8% remains in the recrystallization and secondary drawing textures. The wire heavily drawn at first is restored no longer mechanical properties by annealing and secondary drawing. The first drawing textures in the wires drawn by 50.5 and 71.8% disappears by annealing, and the strength increases with increase in the secondary drawing ratio.

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The minimum solute concentration in dendrite arms and the amount of non-equilibrium eutectic phase were measured in Al-4.5% Cu and Al-6.3 and 10.4% Mg alloys uni- and non-directionally solidified. When the alloys are unidirectionally solidified and arrayed columnar dendrites grow, the minimum solute concentration is high at the initial stage of solidification and the solute remarkably condenses at the center and the growing interface of the arms during solidification. The arms grow being accompanied with a solute-enriched layer in the liquid and with a steep concentration gradient in the arms. If cooling is accelerated and the effective distribution coefficient is increased, the minimum solute concentration increases and the amount of non-equilibrium eutectic decreases. When the alloys are non-directionally solidified and equiaxed dendrites grow, nearly the opposite phenomena are encountered.

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Intergranular corrosion susceptibility of 3003 alloy is intensified by heat treating at elevated temperatures at 400°C or more. 3003 alloy heat treated at elevated temperature is more susceptible to intergranular corrosion, as the Cu content in the alloy is increased. Intergranular corrosion in 3003 alloy is distinctly related to precipitation behaviors of metallic compounds Al₆Mn or Al₆(MnFe). Nuclei for precipitation such as dislocations, deformation stress etc. instantaneously disappear by heat treating at elevated temperatures. Precipitation consequently occurs preferentially in grain boundaries and the alloy is more susceptible to intergranular corrosion.

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Aging behavior and structures of an Al-2.26wt%Li alloy were studied by means of hardness and electrical resistivity measurements and transmission electron microscopy. Increases in hardness and electrical resistivity are caused by homogeneous precipitation of spherical δ' phases at aging temperatures below 200° and 150°C, respectively. It is suggested that excess vacancies are almost confined in the δ' phase during aging, because of the aging structure free from dislocation loops. The phase change from δ' to δ is unlikely to occur at 250°C. The "petal-like", precipitation of δ' phase appears in the alloy directly quenched and aged at 200°C.

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