A direct look at how dislocations moveWednesday (26.09.2018) 16:30 - 17:00 S1/01 - A4 Part of:
We have recently demonstrated that direct molecular dynamics (MD) simulations of single crystal plasticity are not only feasible, but deliver a wealth of important observations on fundamental mechanisms of dynamic response that define plasticity and strength of metals [Nature 550, 492–495 (2017)]. Our simulations are cross-scale rather than multi-scale, i.e. simultaneously large enough to represent macroscopic crystal plasticity and yet fully resolved, tracing every “jiggle” of atomic motion.
To deal with the overwhelming complexity of processes on these scales, we develop advanced computational methods and tools to recast the massive transient trajectory data generated in such large-scale MD simulations into a human comprehensible and analyzable form using methods of “in-situ computational microscopy”. These algorithms automatically identify grain boundaries, dislocations, other defects, structural phases and deformation fields and can track their evolution. The data reduction and transformation of the underlying MD model into higher-level representations of the microstructure enable insightful visualizations and quantitative analyses.
In particular, a novel computational method will be introduced for reconstructing the slip surfaces generated by gliding dislocations in atomistic models. Slip surfaces describe the precise paths taken by dislocation defects moving through the crystal lattice and they can be reconstructed from MD trajectories. The new method constitutes a powerful analysis tool that can deliver valuable insights into the microscopic behavior of dislocations, slip system activity, glide velocities and reaction events.