Molecular dynamics simulations of shock-induced plasticity in tantalum

We present Non-Equilibrium Molecular Dynamics (NEMD) simulations of shock wave compression along the [001] direction in monocrystalline Tantalum, including pre-existing defects which act as dislocation sources. We use a new Embedded Atom Model (EAM) potential and study the nucleation and evolution of dislocations as a function of shock pressure and loading rise time. We find that the flow stress and dislocation density behind the shock front depend on strain rate. We find excellent agreement with recent experimental results on strength and recovered microstructure, which goes from dislocations to a mixture of dislocations and twins, to twinning dominated response, as the shock pressure increases. Fil: Tramontina Videla, Diego Ramiro. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Ministerio de Ciencia. Tecnología e Innovación Productiva. Agencia Nacional de Promoción Cientifíca y Tecnológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina Fil: Erhart, Paul. Lawrence Livermore National Laboratory; Estados Unidos. Chalmer University of Technology; Suecia Fil: Germann, Timothy. Los Alamos National Laboratory; Estados Unidos Fil: Hawreliak, James. Los Alamos National Laboratory; Estados Unidos Fil: Higginbotham, Andrew. University of Oxford. Department of Physics; Reino Unido Fil: Park, Nigel. Atomic Weapons Establishment. Materials Modeling Group; Reino Unido Fil: Ravelo, Ramón. Los Alamos National Laboratory; Estados Unidos. University of Texas at El Paso; Estados Unidos Fil: Stukowski, Alexander. Universitat Technische Darmstadt; Alemania Fil: Suggit, Mathew. University of Oxford. Department of Physics; Reino Unido Fil: Tang, Yizhe. University Johns Hopkins; Estados Unidos Fil: Wark, Justin. University of Oxford. Department of Physics; Reino Unido Fil: Bringa, Eduardo Marcial. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina