Abstract
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Molecular dynamics simulations were carried out to investigate the mechanical property and the
deformation mechanisms of Cu bicrystal with non-planar structured grain boundaries(GBs) under
uniaxial tension and compression. The simulation results showed that the non-planar GBs could
change their equilibrium configurations under the applied stress, and the deformation mechanisms
varied when altering the misorientation angle. The stacking fault energy curve was affected by the
stress perpendicular to the slip plane and therefore has an influence on the dislocation nucleation
mechanisms. Previous studies have revealed a ubiquitous tension/compression (T/C)strength
asymmetry of many ultra-fine or nanocrystalline materials, and a higher compressive strength was
usually reported. However, in the present study, the bicrystal samples with non-planar structured GBs
show a higher tensile strength than the compressive one. The unusual T/C asymmetry property has an
implication that the GBs with non-planar structure can play a significant role in affecting the
mechanical properties of nanostructured materials.