7th International Conference on Matter and Radiation at Extremes (ICMRE2024)

With large-scale non-equilibrium molecular dynamics simulations and in situ X-ray Diffraction analysis, we conducted a systematic investigation into the effects of pre-existing shear strain (γ_xy) on the shock response of single crystal iron. Our findings reveal significant effects of γ_xy on the deformation of the crystal structure during shock loading, leading to noticeable alterations in the propagation of shock waves. Specifically, during the elastic stage, the presence of γ_xy results in a reduction of shock strength, consequently diminishing the magnitude of elastic lattice strain (ε_e). In theplastic stage, γ_xy stimulates the α–ε phase transformation, and structure deformation undergoes a transition from the sequential activity of dislocation-to-transformation to the synchronous activity of dislocation and transformation. This transition inhibits the propagation of plastic waves and consequently broadens the elastic regime. Additionally, the introduction of γ_xy activates different slip systems, as it alters the corresponding resolved shear stress. Concurrently, the presence of γ_xy triggers the activation of different high-pressure phase variants. Our investigation sheds light on the fundamental physics of iron under shock compression and the influence of pre-existing shear strain on its behavior.

shock,phase transformations,plasticity,iron,XRD