Atomistic simulations of twin facets associated with three-dimensional {1011} twins in magnesium

Twinning is a deformation mechanism that creates three-dimensional (3D) twin domains through the migration of twin facets. This occurs via the nucleation and glide of twinning disconnections (TDs), which can pile up to create twin facets. A comprehensive understanding of twin facets associated with 3D twins, including their atomic structures and energies, is crucial for understanding deformation twinning. In this study, we propose a molecular statics/dynamics (MS/MD) approach to determine characteristic twin facets enclosing 3D non-equilibrium/equilibrium {1011} twin domains, which has been much less studied than the counterpart {1012} twin domains. The stability of different TD pile-up arrangement with varying line senses informs the morphology of 3D non-equilibrium twins, which are bounded by {1010}_T||{1013}_M, {1011}_T||{0002}_M and {1013}_T||{1013}_M coherent facets associated with pile-up of edge TDs, and discrete non-edge TDs aligned along CTBs with their line senses parallel to <4513>, <1101>, <5416> <2113>or <1012> axes. Formation of semi-coherent facets of equilibrium twins is accompanied by rearrangement of TDs around misfit dislocations. 3D equilibrium {1011} twins may comprise {1011}_T||{0002}_M, {1457}_T||{3419}_M, {1657}_T||{5617}_M, {1433}_T||{3413}_M, {0110}_T||{0111}_M and {0221}_T||{0221}_M semi-coherent facets in <1210>, <4513>, <1101>, <5416>, <2113> and <1012> axes, respectively.