par Germann, Timothy C.;Holian, Brad Lee;Lomdahl, Peter S.;Tanguy, Dome;Mareschal, Michel ;Ravelo, Ramon
Référence Metallurgical and Materials Transactions A - Physical Metallurgy and Materials Science, 35, 9, page (2609-2615)
Publication Publié, 2004
Article révisé par les pairs
Résumé : Large-scale molecular dynamics simulations are used to investigate the dislocation structure behind a shock front in perfect fcc crystals. Shock compression in both the (100) and (111) directions induces dislocation loop formation via a sequential emission of partial dislocations, but in the (100) case, this process is arrested after the first partial, resulting in stacking-fault loops. The large mobility of the bounding partial dislocations results in a plastic wave that is always overdriven in the (100) direction; the leading edges of the partials are traveling with the plastic front, as in the models of Smith and Hornbogen. In contrast, both partials are 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 are periodically nucleated at the plastic front, as suggested by Meyers.