On the nucleation and growth of voids at high strain-rates

The nucleation and growth of voids at high strain-rate is studied in copper as a model face centered cubic (fcc) material using large scale molecular dynamics (MD) methods. After a brief introduction to dynamic fracture, results are presented for the homogeneous nucleation of voids in single crystal copper and the heterogeneous nucleation in nanoscale polycrystalline copper. The simulations suggest void growth occurs through anisotropic dislocation nucleation and emission in agreement with experiment and the observed anisotropy of the tensile flow stress in fcc crystals. A phenomenological model for the transition from intergranular to transgranular fracture at high strain-rate is presented. This revised version was published online in July 2006 with corrections to the Cover Date.