The effect of tension twin on the dynamic recrystallization behavior in polycrystal magnesium by atomistic simulation

Abstract

To investigate the $$\{10\bar{1}2\}$$ tension twin effects on the dynamic recrystallization structure evolution in magnesium alloys, the compression deformation of a magnesium polycrystal containing an initial $$\{10\bar{1}2\}$$ tension twin under different loading directions was simulated by molecular dynamics method. The results showed that the dynamic recrystallization phenomena only occurred when loading normal to twin boundary. By tracking atoms’ motion, it was found that the twin dynamic recrystallization microstructure evolution could be divided into two steps. Step one: basal partial dislocations nucleated near twin boundary, leading to large area of stacking faults; Step two: due to the accumulation of strain energy, non-basal slip systems nucleated in the stacking faults region, promoting the stacking faults to recover to hexagonal close-packed structure and forming the new grains. When loading parallel to twin boundary, the twin boundary migration dominated the deformation process, which released the strain energy and inhibited the nucleation of dynamic recrystallization.