Molecular Dynamics Simulations of Plane Shock Loading in SiC

Large-scale molecular dynamics simulations are carried out to investigate 3C-SiC single crystals under plane shock loading. From the analysis of the shock profile and the evolution of the atomic structures, we demonstrate the interplay between the shock induced elastic compression, plastic deformation, and structural phase transformation (SPT). Particle velocity ranges from 0.4-6.0 km/s. The predicted shock Hugoniot is divided into four regions. Below 2 km/s, only elastic shock induced compaction exists. Plastic deformation appears between 2-3 km/s, while the SPT emerges above 3 km/s, when the induced pressure reaches over 90 GPa. Plastic deformation in this cubic crystalline material is marked by extensive deformation twinning while at high pressure the original low pressure zinc blend structure is transformed into the more compact rocksalt structure. For particle velocity above 4.5 km/s, a single overdriven transformation wave propagates in the system. These simulation results provide an atomistic view of the dynamic effects of shock impact on single crystal high-strength ceramics.