Effect of Si Content on Dynamic Recrystallization of Al–Si–Mg Alloys During Hot Extrusion

By using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM), the effect of Si content on microstructure characteristics of three as-extruded Al–Si–Mg alloys was investigated. Results showed that the density of coarse Si particles played a critical role in dynamic recrystallization. Dynamic recrystallization rarely occurred in S1 alloy with less Si content; however, it happened in the Si-rich zones in S2 alloy with a medium Si content. And a mature recrystallization was observed in S3 alloy with high Si content. Although deformation was carried out at high temperature, particle-stimulated dynamic recrystallization occurred in Si-rich zones.