The impact of a variety of point defects on the inception of plastic deformation in dislocation-free metals

Atomistic simulations of nanoindentation tests were used to quantify the effect of point defects (a single vacancy, a di-vacancy, a self interstitial atom and a stacking fault tetrahedron) on the onset of plasticity in copper. The stacking fault tetrahedron reduces the pressure needed to nucleate a dislocation by almost half of that of the perfect crystal. Reduction in the normalized yield pressure relative to the perfect crystal for a given defect is independent of indenter size.