Additions of Zn can significantly improve the age-hardening response of binary Mg-Sn alloys by refining the distribution of Mg2Sn precipitates, but its role in the precipitation is still unclear. In this study, the Mg2Sn precipitates with different morphologies and orientations in a Mg-9.8Sn-1.2Zn (wt.%) alloy are characterized by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and STEM X-ray mapping. It is found that Zn atoms invariably segregate to the Mg2Sn-Mg interface, irrespective of the interfacial structures and orientation relationships of Mg2Sn. This finding provides insight to the understanding of the enhanced nucleation of Mg2Sn precipitates in Mg-Sn-Zn alloys.
- Interface segregation
- Magnesium alloys