Energy and stochasticity: the yin and yang of dislocation patterning
Nipal Deka, Coleman Alleman, Douglas L. Medlin, Ryan B. Sills
Abstract
Dislocations form patterns that strongly influence mechanical properties. Prevailing theories are dichotomous: patterns either form by energy minimization or stochasticity during plastic flow. Using discrete dislocation dynamics simulations, it is shown that both energy and stochasticity contribute to patterns. Monte Carlo simulations reveal that short-range forces between dislocations lead to wall-like structures, while long-range forces control the wall thickness. Perturbation simulations demonstrate that persistent, low-density regions form when the network is perturbed over sufficient deformation. These findings suggest a two-stage process where stochasticity forms low-density regions, which then lead to confined walls through local energy minimization.