Interface segregation of solute atoms significantly influences the mechanical properties of magnesium alloys, though the underlying mechanism remains elusive. Here we directly observe the migration dynamics of a Nd segregated 10Formula: see text2 twin boundary (TB) via in-situ TEM. The TB exhibits discontinuous, hopping motion with a decreased stress accumulation period. Crucially, most segregated Nd solute atoms do not co-migrate with the advancing TB, consequently inducing high-density stacking faults. This work experimentally clarifies the atomic-scale pinning mechanism of RE segregation on TBs, offering insights into tailoring twinning behavior for optimizing the strength and ductility of magnesium alloys.
Li et al. (2026) studied this question.