Effect of twin boundary on the initial yield behavior of magnesium nanopillars under compression: molecular dynamics simulations

Nanotwinned Mg nanopillars under uniaxial compression were investigated by molecular dynamics simulations. The simulation results indicate that more $\left\{10\overline{1}1\right\}⟨10\overline{1}\overline{2}⟩$ TBs and less $\left\{10\overline{1}2\right\}⟨10\overline{1}\overline{1}⟩$ TBs are recommended to introduce for obtaining Mg nanopillars being of higher compressive yield strength. The pre-built $\left\{10\overline{1}1\right\}⟨10\overline{1}\overline{2}⟩$ TBs restrains the nucleation of new twins, and subsequently causes the increase of the yield strength. The initial yield behavior of nanotwinned Mg nanopillars with $\left\{10\overline{1}1\right\}⟨10\overline{1}\overline{2}⟩$ TBs was found to be twinning nucleation, and the nucleation mechanism is a shuffling mechanism. The introduction of $\left\{10\overline{1}2\right\}⟨10\overline{1}\overline{1}⟩$ TBs bring sources of dislocations into Mg nanopillars and subsequently causes the decrease of yield strength. (paper)