Evolution of Microstructure in Al-Mn Alloy with a Low Ratio of Fe/Si During Homogenization

The evolution of microstructure in Al-Mn alloy with a low ratio of Fe/Si produced by twin-roll casting (TRC) during various homogenization treatments was investigated. The grain structure near the surface transforms from fibrous to coarse elongated recrystallized grain structure during homogenization at 550 °C for 4 h. The grain in the interior tends to be equiaxed with the temperature increasing. The primary particles are broken up after homogenization at 450 and 500 °C for 4 h, and coarsened when the temperature increases to 550 °C. The evolution of dispersoids is controlled by nucleation and growth mechanisms at 450 and 500 °C for 4 h, whereas the coarsening and dissolution are predominant mechanisms during homogenization at 550 °C for 4 h. Many small Zr-bearing dispersoids are obtained during homogenization at 500 °C for 4 h.