Elastic-plastic collapse of super-elastic shock waves in face-centered-cubic solids

[摘要] Shock waves in the [110] and [111] directions of single-crystal Al samples were studied using molecular dynamics (MD) simulations. Piston-driven simulations were performed to investigate the split shock-wave regime. At low piston velocities, the material is compressed initially to a metastable over-compressed elastic state leading to a super-elastic single shock wave. This metastable elastic state later collapses to a plastic state resulting in the formation of a two-wave structure consisting of an elastic precursor followed by a slower plastic wave. The single two-zone elastic-plastic shock-wave regime appearing at higher piston velocities was studied using moving window MD. The plastic wave attains the same average speed as the elastic precursor to form a single two-zone shock wave. In this case, repeated collapse of the highly over-compressed elastic state near the plastic shock front produces ultrashort triangle pulses that provide the pressure support for the leading elastic precursor.

[发布机构] University of South Florida, 4202 East Fowler Avenue, Tampa; FL; 33620-5700, United States^1;Landau Institute for Theoretical Physics, RAS, Chernogolovka, Russia^2;Naval Research Laboratory, Washington; DC; 20375-5320, United States^3

[关键词] Elastic state;Elastic-Plastic;Face-centered cubic;Molecular dynamics simulations;Moving window;Piston velocity;Pressure support;Single-crystal Al