Elucidating dynamic recrystallization and superplastic deformation mechanisms in Al-Cu-Li alloy by using quasi-in-situ EBSD

Combining quasi-in-situ EBSD and FIB-aided surface study, this work unveils the mechanisms of dynamic recrystallization (DRX) and superplastic deformation in an as-rolled Al-Cu-Li alloy. At early deformation stage (ϵ = 50%), low-angle grain boundaries and banded grains dominate, with superplastic flow governed by intragranular dislocation slip (IDS). With increasing strain, continuous DRX through dynamic recovery and sub-grain rotation resulting in a fully recrystallized structure, enhancing grain boundary sliding (GBS) and strain rate sensitivity. As the main superplastic deformation mechanism of the second stage (ϵ = 300%), GBS is mainly accommodated by local DRX and IDS.