An atomic and probabilistic perspective on twin nucleation in Mg

We discuss the nucleation of deformation twins in Mg from a fundamental perspective. Atomistic simulations reveal twinning mechanisms and suggest that twin nucleation most likely occurs at grain boundaries (GBs). We observe twin nucleation from symmetrical tilt grain boundaries using molecular dynamics and reveal that the nucleation pathway depends on the tilt angle and the GB defect state. In particular, twin nucleation is preferred at GBs with low misorientation angles, in agreement with electron back-scattering diffraction (EBSD) analyses. A probabilistic description of twin nucleation is then proposed with the aim of linking atomic-scale information with meso-scale EBSD statistical analyses.