Evolution of microstructure and texture during homogenization in a strip cast AA8011 aluminum alloy

Abstract

The present study investigates the effect of homogenization on microstructures and texture evolution in a TRC i.e. twin roll cast Al-Fe-Si aluminum alloy (AA8011). TRC AA8011 alloy with an initial thickness of 7 mm was cold rolled upto 50% thickness reduction and homogenized at 580 °C for different times (4h, 8h, and 12h). The initially elongated grains (due to TRC) were further deformed and transformed into a banded structure after cold rolling and the large Al-Fe-Si particles in the as-cast microstructure also reduced in size. After homogenization, the elongated banded grain structure changed to an equiaxed structure and the second phase particles Al-Fe-Si became finer (~2 μm) and more uniform. The near needle shaped second phase particles present in the deformed structure became rounded, which is beneficial for deformability. However, the centerline segregation (CLS) was not removed even after homogenization. Initial TRC AA8011 alloy had a very weak texture consisting of Brass ({110} <112>), Goss ({110} <001>), S ({123} <634>) and Cube ({100}<100>). After cold rolling, Brass, Goss, and S strengthened, while Cube ({100}<100>) decreased at mid-thickness of the samples. At the surface, the deformation texture was predominantly near Brass. At mid-thickness, homogenization at 580 °C improved Cube in general, and the maximum Cube texture was obtained for 8 h (~7.7%) along with weak Brass and Goss. The deformation texture components were absent at the surface with minor variation in Cube.