Atomistic simulations of twin facets associated with three-dimensional {1¯011} 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 {1¯011} twin domains, which has been much less studied than the counterpart {1¯012} 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 {101¯0}T||{1¯013}M, {101¯1}T||{0002}M and {101¯3}T||{101¯3}M coherent facets associated with pile-up of edge TDs, and discrete non-edge TDs aligned along CTBs with their line senses parallel to <45¯13>, <11¯01>, <54¯1¯6> <21¯1¯3>or <101¯2> axes. Formation of semi-coherent facets of equilibrium twins is accompanied by rearrangement of TDs around misfit dislocations. 3D equilibrium {1¯011} twins may comprise {101¯1}T||{0002}M, {145¯7}T||{34¯19}M, {1¯65¯7}T||{56¯17}M, {1¯43¯3}T||{34¯13}M, {011¯0}T||{011¯1}M and {02¯21}T||{02¯21}M semi-coherent facets in <12¯10>, <45¯13>, <11¯01>, <54¯1¯6>, <21¯1¯3> and <101¯2> axes, respectively.