The Modeling and Simulations Group is conducting simulations of the processes of material deformation using large-scale molecular dynamics (MD). The process of twinning is an important deformation mechanism in low-symmetry crystals and metals deformed at high rates or low temperatures. We have used the ddcMD code to simulate twinning in nanocrystalline materials (see figure), as well as to simulate specific processes associated with twinning in high rate deformation. Much of this work to date has focused on the body-centered cubic metal tantalum. In order to carry out large-scale MD simulations, we also develop interatomic potentials. We develop fitting databases consisting of the results of first principles (DFT) calculations. We emphasize mechanical and defect properties in our fitting databases.

High-rate Deformation of Metals by Twinning

Interatomic Potentials