Phases equilibrated with long-period stacking ordered phases in the Mg-rich corner of the Mg-Y-Zn system

Phase equilibria involving the long-period stacking ordered phases including 14H, 18R and 10H in the Mg-rich corner of the Mg-Y-Zn system at 400 and 500 degrees C have been experimentally investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The coexistence of 14H and 18R as well as 18R and 10H was confirmed from atomic scales. The phases 14H, 18R and 10H were all stable phases from 400 to 500 degrees C.The experimentally proved three-phase equilibrium of 14H, 18R and alpha-Mg instead of 14H, 18R and Mg24Y5 were presented in the modified isothermal sections. The latter three-phase equilibrium was reported in the available literature. The modified isothermal sections are conducive to guide the composition design to obtain the alloys with favorable microstructure constituents and mechanical properties. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

The experimental investigation of phase equilibria involving the long-period stacking ordered phases including 14H, 18R and 10H in the Mg-rich corner of the Mg-Y-Zn system at 400 and 500 degrees C was conducted using various microscopy techniques. The stable phases and three-phase equilibrium relationships were confirmed, and guidance for alloy composition design was provided based on modified isothermal sections.