Large-scale molecular dynamics simulations were used to investigate the dislocation structure behind a shock front in perfect face-centered cubic crystals. Shock compression in both the <100> and <111> directions induced dislocation loop formation via a sequential emission of partial dislocations, but in the <100> case, this process was arrested after the first partial, resulting in stacking-fault loops. The large mobility of the bounding partial dislocations results in a plastic wave that was always overdriven in the <100> direction; the leading edges of the partials were travelling with the plastic front, as in the models of Smith and Hornbogen. In contrast, both partials were emitted in <111> shock compression, resulting in perfect dislocation loops bounded only by thin stacking fault ribbons due to the split partial dislocations. These loops grow more slowly than the plastic shock velocity, so new loops were periodically nucleated at the plastic front, as suggested by Meyers.

Dislocation Structure behind a Shock Front in FCC Perfect Crystals - Atomistic Simulation Results. T.C.Germann, D.Tanguy, B.L.Holian, P.S.Lomdahl, M.Mareschal, R.Ravelo: Metallurgical and Materials Transactions A, 2004, 35[9], 2609-15