Quantitative aspects of shock-induced dislocation nucleation were investigated by means of molecular dynamics simulations of face-centered cubic Lennard-Jones solids. In perfect crystals, it was found that the Hugoniot elastic limit was a linearly decreasing function of temperature, from near-zero to the melting point. In a defective crystal with a void, dislocations were found to nucleate on the void surfaces. The Hugoniot elastic limit decreased sharply to 15% of that of the perfect crystal when the void radius was 3.4nm. The decrease in the Hugoniot elastic limit became larger as the void radius increased, but the Hugoniot elastic limit became insensitive to temperature.

Dislocation Nucleation in Shocked FCC Solids - Effects of Temperature and Pre-Existing Voids. T.Hatano: Physical Review Letters, 2004, 93[8], 085501 (4pp)