Dislocation Dynamics Simulations of Junctions in Hexagonal Close-Packed Crystals

摘要

The formation and strength of dislocations in the hexagonal closed-packed material are studied through dislocation junctions and the critical stress required to completely break them. Dislocation dynamics calculations of junctions are compared to an analytical line tension approximation in order to verify the simulations. Results show agreements between the models. Also the critical shear stress necessary to break a short and a long dislocation junction is computed numerically. Unzipping envelopes are mapped out for these junctions to describe their stability regions as functions of resolved shear stresses on the glide planes. The example of two non-coplanar binary dislocation junctions with slip systems [2 -1 -1 0] (0 1 -1 0) and [-1 2 -1 0] (0 0 0 1) corresponding to a prismatic and basal slip respectively is chosen to verify and validate our implementation.