화학공학소재연구정보센터
Materials Science Forum, Vol.408-4, 1489-1494, 2002
Texture evolution of AA5052 during monotonic and reversed hot deformation and subsequent recrystallization
During industrial thermomechanical processing such as forging, rolling and extrusion, local regions within the stock undergo different strain paths. A significant effect of a change in strain path on microstructural evolution and subsequent recrystallisation behaviour has been observed previously for several texture free Al-Mg alloys under conditions of hot deformation in tension/compression. The mechanism of the effect is related to the evolution of geometrically necessary dislocations including the evolution of microbands, which are heterogeneously distributed in deforming materials and depend upon the orientation of grains. This work is currently being extended to texture evolution during continuous and reversed deformation. The combined effects of strain path on dislocation substructures and on deformation texture determine the subsequent recrystallisation behaviour and recrystallisation texture, which in turn dominate deep drawing properties of sheets. The present paper shows the effect of a change in strain path on the evolution of texture during either simple shear or axisymmetric deformation of AA5052 and during annealing of the deformed materials. The experimental alloy has initial Goss and Cube texture components. The simple shear was carried out in a reversible torsion machine and axisymmetric deformation in a tension/compression-testing machine. Texture was examined both using an X-ray texture goniometer and by electron backscattered diffraction (EBSD) in a scanning electron microscope. The results show that the evolution of texture is different during monotonic and reversed shear deformation. After annealing to partially recrystallise, the difference of orientation distribution becomes more significant than in the specimens deformed in torsion. After annealing for a short time, where no recrystallisation can be found, the texture components are different from the partially recrystallised specimens.