Structural characterization of Laves-phase MgZn₂ precipitated in Mg-Zn-Y alloy

Abstract

Structural characterization of Laves-phase MgZn₂ precipitated in Mg-6 wt.%Zn-1 wt.%Y alloy was performed using a high-resolution transmission electron microscope (HRTEM). Plate- and rod-shaped precipitates with the Laves structure were observed in an aged sample at 200 °C. An individual rod of the β₂′ phase precipitated in the matrix contained several domains with various orientations. Numerous antiphase boundaries (APBs) and stacking faults (SFs) were observed in the β₂′ precipitates. The stacking sequence of the 14C structure partially changed to that of the C15 structure due to the presence of a stacking fault. The orientation relationship between the C14 structure and the C15 structure in the β₂′ precipitates was [11–20]_C14‖[1–10]_C15 and (0001)_C14‖(111)_C15. Modification of the stacking sequence based on the synchroshear mechanism was discussed.