Molecular dynamics study on nanoscale void collapse in single crystal aluminum under 1D and 3D compressions

The nanoscale void collapse in single crystal aluminum under 1D and 3D compressions at extremely high strain rate was investigated by molecular dynamics. Our simulations reveal the formation of two intersecting tetrahedrons around the void under 3D compression, rather than the shear dislocation loops under 1D compression. The formed tetrahedrons prevent the continuous growth of the shear dislocation loops, which therefore makes the void collapse slow down. For both 1D and 3D compressions, the void collapse is mainly along the three principal axes of stress, resulting in a four-pointed star cross-section of the void along the {1 0 0} plane. The above features are effected by void size and initial temperature.