Massively Parallel Simulation of Vacancy-Jog Interaction with ParSplice

Dallas Trinkle, University of Illinois at Urbana-Champaign

Usage Details

We plan to use the massively parallel program ParSplice—running on top of the molecular dynamics code LAMMPS—to simulate long time trajectories for a vacancy diffusing near a dislocation jog in nickel. Unlike most multiscaling approaches, ParSplice is designed specifically to simulate large times rather than large spatial domains; moreover, it shows excellent parallel scaling to large numbers of cores. The simulation we propose will quantify the rate of reaction for a vacancy and a dislocation jog in nickel: a fundamental atomic-scale process for the climb of a dislocation, which in turn controls creep (high temperature time-dependent strain due to a time-independent load). Creep is the primary design criterion in materials for jet turbine blades, and nickel is the primary constituent in nickel-based superalloys for such applications. Despite the crucial nature of this work, the long simulation times needed have been prohibitive to computational study. Now, with ParSplice and access to a very large number of cores on Blue Waters, we will be able to achieve the appropriate time scales to study how vacancies and dislocation jogs interact.