Atomistic investigation of anisotropic shock Hugoniot and mechanical behavior in oriented α-quartz single crystals under equilibrium shock states

Through atomistic modeling, this study systematically investigated the anisotropic shock Hugoniot and probed the mechanical behavior of oriented α-quartz single crystals under equilibrium shock states. With the Tersoff Si-O force field to describe the interatomic interactions, we utilized molecular dynamics simulations in conjunction with the multi-scale shock technique (MSST) and explored the shock response along crystal orientations of [100], [120], and [001]. Our computations characterized the distinct anisotropic thermodynamic properties and revealed the “two-wave” feature in shock Hugoniot, indicating polymorphic transformations under shock loading. Additionally, this study also elucidated the elastic-plastic transition and provided a critical aspect of material behavior under dynamic compression. The shock Hugoniot results predicted by our simulations show very good agreement with previously reported experimental data. By monitoring the statistics of bond distributions, our work included quantitative analyses on the Hugoniot elastic limit and dynamical structural evolution. Unloading tests corroborated the elastic properties of shocked α-quartz, confirming the preservation of crystal properties prior to the destruction. This study sheds light on the anisotropic mechanical behavior of α-quartz and contributes to a deeper understanding of the shock-induced thermodynamic and structural changes, with the additional support of single-point energy calculations that further validate the structural transformations. The results have broad implications for material science and engineering applications, particularly in contexts involving inelastic material deformations, high-pressure environments of typical impact events, explosive-driven shock loading, and other high-energy processes.