Microstructure and Its Evolution of Solute-Enriched Stacking Faults in Kink-Deformed Mg₉₇Zn₁Y₂

Microstructure and its evolution of solute-enriched stacking faults (SESFs) in kink-deformed Mg–Zn–Y alloys have been investigated by scanning transmission electron microscopy (STEM). Mass-thickness contrast in annular dark-field (ADF) STEM images and diffraction contrast in weak-beam dark-field (WBDF) STEM images visualized locations of solute-enriched regions and dislocations, respectively. Most of the SESFs are located at or near kink boundaries, and a variety of arrangements and morphology of the SESFs are followed by dislocations with the c component of α-Mg matrix and small-angle lattice rotations along the c-axis as well as the a-b axes. As notable microstructural features of the SESFs, rectangular-shaped and step-shaped arrangements of the SESFs, observed respectively before and after a heat treatment at 573 K for 168h, were observed in detail, and their formation processes were discussed.