The effects of long-range and short-range interactions on the early stress–strain response and dislocation density evolution in hexagonal close-packed metals were studied using three-dimensional discrete dislocation dynamics. To examine long-range interactions, the dislocation dynamics code was developed such that elastic stress fields between interacting dislocations were calculated by either enforcing elastic isotropy or considering the actual elastic anisotropic constants of the hexagonal close-packed metal. To improve treatment of short-range interactions, a set of local rules for the behavior of closely interacting dislocations was implemented. In particular, a new scheme for elastic repulsion in the event of repulsive short-range interactions was presented and found to have a significant effect on the stress–strain response and dislocation density evolution. Large-scale simulations were performed for 3 hexagonal close-packed single crystals (Hf, Mg, Zr) in c-axis tension to examine the effect of elastic anisotropy on the collective response of several interacting dislocations. It was found that departure from isotropic elasticity has a substantial effect on strain hardening, particularly for Hf.

The Role of Elastic Anisotropy on Plasticity in HCP Metals: a Three-Dimensional Dislocation Dynamics Study. L.Capolungo, I.J.Beyerlein, Z.Q.Wang: Modelling and Simulation in Materials Science and Engineering, 2010, 18[8], 085002