(a) screw dislocation triggered 1011 twinning in magnesium

XY Li and YF Guo and XZ Tang and J Wang, SCRIPTA MATERIALIA, 268, 116853 (2025).

DOI: 10.1016/j.scriptamat.2025.116853

Twin nucleation in hexagonal metals is generally described by successive nucleation and gliding of twinning dislocations/disconnections (TDs). Unusual nucleation mechanisms, such as pure-shuffle mechanism for 1012 twins and kinking mechanism for 1121 twins, had been proposed based on experimental observations and atomistic simulations. Here, we reported screw dislocation enabled 1011 twinning mechanisms in magnesium based on atomistic simulations. A (a) screw dislocation can have a planar spread core on basal plane or develop into a 1011 twin embryo via a cross-slip mechanism. The cross-slip enabled 1011 twinning mechanism is favored when the basal slip is constrained or suppressed at a high strain condition. This mechanism addresses the experimental puzzle of the 1011 twin absence under c-axis compression.

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