Influence of Mo on the dynamic recrystallization behavior of Al–Cu–Mg–Ag alloy

Abstract

High-throughput double cone specimens were used to study the influence of Mo on the microstructure evolution of Al–Cu–Mg–Ag alloy under a wide range of strain along the axis. The microstructure evolution was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). Results demonstrated that Al6(Fe, Mn, Mo) dispersoids formed in the Al–Cu–Mg–Ag alloy with the addition of 0.2% Mo during double-step homogenization. Meanwhile, rod-like Al20Cu2Mn3 and disk-like Al6(Fe, Mn, Mo) dispersoids segregated to opposite distribution in interdendritic regions and dendrite cores, respectively, which obviously eliminated the dispersoid-free zones and intragranular sparse regions. With different effective strains along the axis, Al6(Fe, Mn, Mo) dispersoids obviously reduced the transformation from Low-angle grain boundaries to High-angle grain boundaries. The nucleation and growth of dynamic recrystallization grains were effectively inhibited by the coupling of Al20Cu2Mn3 and Al6(Fe, Mn, Mo) dispersoids due to the obstruction of dislocation movement.