Deformation behavior and dynamic recrystallization during hot compression in homogenized Al-6Mg-0.8Mn alloys

In this work, Al6Mn phases with various sizes and morphologies were achieved in homogenized Al-6Mg-0.8Mn alloys. The homogenized alloys were compressed at 450 degrees C with strain rates of 0.001 s(-1) and 1 s(-1) to investigate the deformation and recrystallization behaviors induced by Al6Mn phases. The microstructure evolution in the alloys homogenized at 360 degrees C and 460 degrees C for 24 h and a two-stage homogenization (TS) was discussed. The results demonstrated that the homogenization had a good effect on improving the segregation of Mg elements and dendritic structures in the alloys. The low homogenization temperature of 360 degrees C resulted in the generation of a large number of nano-sized Al6Mn phases, which caused a high peak flow stress during hot compression. The Al6Mn phases with a large size were formed due to the inhomogeneous precipitation when the homogenization temperature was 460 degrees C. The Al6Mn phases with a large volume fraction and a small size in the alloy homogenized at "TS" were beneficial for promoting the recrystallization process and inhibiting the growth of recrystallized grains. In addition, in terms of pinning and driving forces for dynamic recrystallization, the role of Al6Mn phases participated in the alloys under different homogenization conditions was analyzed.