Al-Mg Alloy Sheet of Excellent Formability for Automobile

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A recrystallization texture whose (111) plane is arranged parallel to the rolling plane has scarcely been found in fcc metals and alloys. The improvement of Lankford value in Al-Mg and Al-Mg-Si alloys for automobile can be expected, if the (111) recrystallization texture is developed. A recrystallization texture consisting of near (123) [143] and near (123) [931] orientations was formed in the surface layr of aluminum sheet having the (001) [110] shear texture. One of the four {111} poles of those orientations lies near the center of (111) pole figure. Since the shear texture constitutes a component of hot-rolling textures in aluminum, the development of the (001) [110] shear texture can be predicted in the Al-Mg alloy warm-rolled just below the recrystallization temperature. In this study hot-rolled plates of Al-4.0Mg, Al-4.0Mg-0.1Fe-0.1Si and Al-5.5Mg alloys of 5mm in thickness were warm-rolled to 85% in the temperature range from 250ﾟC to 300ﾟC.The formation of a (111) recrystallization texture and the through thickness texture gradient to the R orientation as well as the effect of the (111) recrystallization texture on the improvement of r value were examined. A (111) [110] shear texture was formed up to the inner layrs 25-30% below the surface, both in the Al-4.0Mg-0.1Fe-0.1Si and Al-5.5Mg alloys rolled at 280ﾟC and 300ﾟC.After annealing a (111) recrystallization texture to be described anyhow as a (111) [110] orientation was generated with a large spread within the half thickness to the center of the sheet having the (111) [110] shear texture. An average r value higher than 1.3 was obtained but its anisotropy within the rolling plane was much larger than industrial products.