A rotation-shear model on the atomic motion during {101̅2} twinning in magnesium alloys

•A new model on the atomic motion during {101̅2} twinning in magnesium is presented.•The movement of twinned atoms in this model is considered as the combination of a rotation of the parallelogram units by 16° and a shear along [1̅011].•The absolute motion vector of twinned atoms is calculated and summarized into general formulae, which implies the intrinsic periodicity of atomic motion vector.

A newly developed rotation-shear model on the atomic motion during {101̅2} twinning in magnesium and its alloys is proposed. In this model, the movement of the twinned atoms is considered as the combination of a rotation by 16° and a subsequent shear along the twinning direction [1̅011]. Besides, the absolute motion vectors of atoms located in certain atom layers are calculated and summarized into general formulae, by which the movement of any specific atom during twinning can be predicted accurately.