Grain growth kinetics and annealed texture characteristics of Mg-Sc binary alloys

The effect of scandium on the microstructure and texture of hot rolled and annealed binary Mg-Sc alloys has been studied. Hot rolled alloys develop weaker and more random basal texture than the corresponding texture of pure Mg after undergoing the same thermomechanical processing. The increase of Sc concentration leads to a systematic weakening of the texture, however texture randomization is not as prominent as in other Mg-RE alloys. The annealed texture of Mg-Sc alloys inherits features of the deformed texture, showing moderately weaker intensities of dominant components. The texture weakening is attributed to the heterogeneous deformation and nucleation of randomly oriented grains at micro shear bands. The microstructure and grain growth analysis suggest that Sc atoms have a low tendency to migrate towards grain boundaries and impose minimal drag effect. As a result, the grain growth is determined by grain boundary self-diffusion with an activation energy of ∼82 ± 8 kJ/mol. The results confirm the important role of solute segregation to grain boundaries in the development of annealed texture in Mg-based alloys.