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 {10 (1) over bar1} < 10 (1) over bar(2) over bar > TBs and less {10 (1) over bar2} < 10 (1) over bar(1) over bar > TBs are recommended to introduce for obtaining Mg nanopillars being of higher compressive yield strength. The pre-built {10 (1) over bar1} < 10 (1) over bar(2) over bar > 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 {10 (1) over bar1} < 10 (1) over bar(2) over bar > TBs was found to be twinning nucleation, and the nucleation mechanism is a shuffling mechanism. The introduction of {10 (1) over bar2} < 10 (1) over bar(1) over bar > TBs bring sources of dislocations into Mg nanopillars and subsequently causes the decrease of yield strength.