Simulation of void growth at high strain-rate

The dynamic fracture (spallation) of ductile metals is known to initiate through the nucleation and growth of microscopic voids. Here, we apply atomistic molecular dynamics modeling to the early growth of nanoscale (2nm radius) voids in face centered cubic metals using embedded atom potential models. The voids grow through anisotropic dislocation nucleation and emission into a cuboidal shape in agreement with experiment. The mechanism of this nucleation process is presented. The resulting viscous growth exponent at late times is about three times larger than expected from experiment for microscale voids, suggesting either a length scale dependence or a inadequacy of the molecular dynamics model such as the perfect crystal surrounding the void.