Non-equilibrium Simulations of Shock-induced Horizontal Defects and Amorphization in 4H Silicon Carbide

RACHEL FLANAGAN; SHITENG ZHAO; ERIC HAHN; CARLOS J. RUESTES; CHRIS WEHRENBERG; BRUCE REMINGTON; M.A. MEYERS

Phoenix

Conferencia; TMS 2018; 2018

The Minerals, Metals & Materials Society

We perform non-equilibrium molecular dynamics simulations of 4H silicon carbide using a modified Stillinger-Weber potential. Using a controlled piston, we produce a shock wave along the [0001] axis and observe the formation of defects along the basal plane, perpendicular to the shock front. The observed defects are unique to the loading direction and the activation of basal slip in the hexagonal system. These shear-driven defects evolve as the shock wave propagates through the system, leading to directional amorphization. Present results agree with experiments where horizontal stacking faults and amorphization are observed following laser shock compression and recovery. Post-mortem HRTEM revealed that above a certain shock threshold, directional amorphous bands are observed in the vicinity of the shock surface. These amorphous bands are either inclined or horizontal to the direction of shock wave, showing agreement between the simulations and the experiment.