Unravelling the {10(1)Over-Bar2} Twin Intersection Between LPSO Structure/SFs in Magnesium Alloy

The effect of long-period stacking ordered (LPSO) structure/solute-rich element laminar stacking faults (SFs) on the intersection of co-zone {10 (1) over bar2} twin variants was uncovered at the atomic scale by TEM. The results show that a basal-prismatic (BP) boundary is generally formed at the intersection of LPSO/SFs and twins, bending the twin boundaries (TBs) into a bow shape between the adjacent LPSO/SFs. The co-zone {10 (1) over bar2} twin variants and LPSO/SFs intersect with each other, introducing a basalbasal (BB) boundary and prismatic-prismatic (PP) boundaries, associated with a triangular matrix near the LPSO/SFs. More Zn atoms than Y atoms were segregated into the TBs. Also, when the LPSO structure is kinked, the {10 (1) over bar2} twin generates and grows on one side of the kink boundary, and the local kink boundary transforms into TB. The growing TB intersects with the residual kink boundary, leaving a triangular matrix near the LPSO/SFs. Multiple twin variants nucleate between the LPSO/SFs/TSFs (twinned stacking faults), and the associated Hall-Petch effect is brought by the segmentation introduced by the intersecting of variants, which can improve the Mg alloy hardening rate. Introducing different twin variants by regulating the LPSO structure's spacing and thickness in magnesium alloy may shed new light on optimizing their performance.