Microstructure and texture of commercial purity aluminum strips produced by melt direct rolling

The microstructure and texture of the aluminum strips produced by the melt direct rolling (MDR) method are inhomogeneous in the direction of strip thickness. The subsurface layer (about 30% thickness of the strips) shows fine and equiaxed grains formed by geometric dynamic recrystallization and has a strong shear texture ([110]//RD fiber texture including {111}[110] and {001}[110] orientations), while the center layer shows elongated grains and has a typical rolling texture. This inhomogeneity is due to large shear deformation induced by friction during rolling. Near the surface, the microstructure shows no remarkable changes during annealing below 673 K, but the relative intensities of {111}[110] and {113}[110] orientations increase. Relatively large (r) over bar and very large Delta r are obtained from the tensile tests of the MDR strip and they vary with the textures depending on annealing temperatures. The present study has clarified that the MDR method is useful to develop the {111} texture in aluminum strip by introduction of large shear deformation during rolling.