  Solute segregation at low angle grain boundaries (LAGB) in Mg alloys
significantly affects GB energy and mobility, therefore recrystallization
kinetics and corresponding texture modification. In a system featuring multiple
substitutional elements at high local concentration levels, solute-solute
interaction needs to be considered to interpret and predict co-segregation
behavior. In this work, atomic-scale experimental and modelling techniques were
applied to investigate the co-segregation behavior of Ca, Zn and Al solutes at
a LAGB in a Mg alloy. Three-dimensional atom probe tomography and corresponding
clustering analysis revealed a strong clustering tendency of Ca solutes at the
linear dislocation arrays. Atomistic simulations indicate that the
co-segregation of Ca-Ca pairs in vicinity of the dislocation core region is
more energetically favorable than other solute pairs, as well as the
segregation of individual solutes.
