Anharmonic effect on the thermally activated migration of {101?2} twin interfaces in magnesium

Using a recent linear scaling method that fully accounts for anharmonic thermal vibrations, we calculated the activation free energy {101¯2} twin boundary migration in magnesium up to 450 K, under both resolved shear stresses and non-glide resulting from c-axis tension. Comparing direct molecular dynamics data, show harmonic transition state theory unexpectedly overestimates entropy above temperatures as low 100 leading underestimates of nucleation time by many orders magnitude. Whilst specific interface is studied, effects are expected be generally significant thermally activated migration.