Segregation of solute atoms along deformation-induced boundaries in an Mg–Zn–Y alloy containing long period stacking ordered phase

Abstract

The interfacial segregation plays an important role in affecting the mechanical performance of various materials. Here we study the segregation behaviors along deformation-induced interfaces in the matrix of an Mg97Zn1Y2 (at%) alloy compressed at 473 K using atomic-scale high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging techniques. The kink boundary, twinning-like boundary, and tilt boundary within the matrix grain are detected to be segregated with both solute Zn and Y atoms. The segregation along kink boundary and twinning-like boundary is closely linked to the associated partial dislocations, and these boundaries also could be regarded as the nucleation sites for the formation of long period stacking ordered (LPSO) structures of nanometer scale and stacking faults (SFs) during deformation. For the various tilt boundary, the segregation could be explained based on either the O-lattice theory or partial dislocations. The experimental results may shed some new light on tailoring microstructures for improving mechanical properties and thermal stability of magnesium alloys.