2018 Volume 67 Issue 2 Pages 215-221
In this study, we perform molecular dynamics simulations to investigate plastic deformation modes of a magnesium (Mg) nanotwinned structure. Periodic units including (1011) twin boundaries (TBs) are analyzed using an embedded atom method potential. Equal spaces between the TBs are assumed at the initial state and the space is parametrized in the range between about 5 nm and 30 nm. It is found that plastic deformation is triggered by the slip along a (1011) twinning plane near a TB, and that this event induces two different deformation modes depending on the space, i.e., the migration of the TBs and the evolution of double twinning, which leads to void nucleation and polycrystallization. The plastic deformation provided by the two different modes is quantitatively verified from geometric analysis. As the space decreases, the migration of the TBs is superior to the evolution of double twinning.
