The effect of texture variation through thickness on bendability of aluminum alloy sheets is studied, using bending tests and numerical simulations. In the experimental investigation, clad sheets were produced by bonding two aluminum sheets in which volume fractions of the cube texture were different. In the bending tests, the specimens were produced such that the volume fraction of the cube texture was higher in an outer surface layer of the sheet than in the inner portion. It was found that the bendability increased with a ratio of thickness of the surface layer that contains a higher volume fraction of the cube texture. The effect of texture variation through the thickness on bendability is clarified by using a crystal plasticity finite element analysis. It is revealed that the bendability is significantly improved even with a rather small volume fraction of the cube texture in the outer surface layer. On the contrary, it drastically declines if a random texture develops in the surface layer.

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Effects of anodizing conditions on corrosion resistance of Mg–Li–Y alloy, which is most prominent super light alloy capable for easy deformation, were investigated with attention to the formation behavior and microstructure of anodic films. Barrier films or semi-barrier films were formed except at around 7 V and breakdown voltages similar to those associated with typical pure magnesium and AZ alloys. At the former voltages, thick porous type films were formed. The critical voltage of high current flow accompanied by breakdown was dependent on substrate composition; 45 V for Mg–Li–Y alloy, 60 V for 99.95% Mg and 120 V for AZ91D. When aluminate or phosphate ion was added in the electrolyte, the critical voltage of Mg–Li–Y alloy increased to 100 V. Lithium was highly enriched at the outer part of the film and yttrium was enriched in the middle to inner part when the film was barrier type. The ratio of barrier film thickness to anodizing voltage was as high as 4.25 nm/V compared to 1.9 nm/V of that associated with 99.95% Mg. When the film was porous type, the content of both lithium and yttrium decreased and distribution of both elements became uniform. Anodic films formed in sodium phosphate solution followed by sealing treatment in silicate exhibited sufficient corrosion resistance for practical usage.

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Deformation behaviors of Al–4.5mass%Cu alloys in semi solid state were investigated with tensile tests and their in situ observation. Deformation behaviors were classified into six stages (from stage I to stage VI, stage I was the lowest temperature range of semi solid state) by mechanical properties, morphologies of fracture surfaces and in situ observations during deformation. In the stages occured hearing (stage V and stage VI), the deformation was caused by flow of liquid phase. Therefore, the elongation could not be evaluated as the ductility of material in these stages. The range of temperature appearing the hot tearing was restricted to narrow temperature range in semi solid state, and was classified to stage II to stage IV. The tensile test method to research deformation behaviors of aluminum alloys in semi solid state with high accuracy was developed.

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The behavior of texture formation in 5182 aluminum alloy was investigated by uniaxial compression tests under strain rates and temperatures ranging from 5.0×10⁻⁴ s⁻¹ to 5.0×10⁻² s⁻¹ and from 673 K to 823 K, respectively. After the deformation, {011} (compression plane) or {001} fiber texture appears. It was found that {001} fiber texture was formed after the development of {011} fiber texture. The size of {001} grains is larger than the average grain size, suggesting that the {001} texture formation is attributed to grain boundary migration. In order to understand the relationship between texture sharpness of {001} , temperature and strain rate, the texture map is proposed. The {001} texture map elucidates that the balance between flow stress and deformation temperature is important for the development of {001} component when the viscous motion of dislocation is the dominant deformation mechanism.

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